摘要:

ay-DIALDEHYDOPROPANE- p P-DICAEBOXYLIC ACID ETC. 19 1 X X X.-a y-Diald ehydopropane-PP-dicarbox ylic and a y -Dialdehydopropane-P-carbox ylic Acid. B y WILLIAM HENRY PERKIN jun. and HERBERT SHEPPARD PINK. THIS communication is a continuation of the work of Perkin and Sprankling (J. 1899,75 1 l) who showed that ethyl acetalmalonate, obtained when ethyl sodiomalonate is heated with bromoacetal, yields on hydrolysis acetalmalonic acid and that this acid when heated with water at 180° loses carbon dioxide with the formation of P-aldehydopropionic acid : (EtO),CH*CH,*CH(CO,Et) -+ (EtQ),CH-CH,*CH(CO,H), -P CHO*CH,*CH,*CO,H. The oxidation of the latter acid to succinic acid its reduction to butyrolactone and its conversion into terephthalic acid by treat-ment with alkali were described.It is now shown that the potas-sium derivative of ethyl acetalmalonate reacts with bromoacetal with the formation of ethyl diacetalmalonate (A) and that this ester on hydrolysis with baryta yields diacetalmalonic acid, (Et O),CH *CH,=C( CO,H),*CH,*CH( OEt),. When the ester (A) is left in contact with N-hydrochloric acid in the cold it is converted into the ester of ay-dialdehydopropane-pp-dicarbozylic acid CHO*CH2*C(C0,Et),*CH2=CH0 but if concen-trated hydrochloric acid is employed further hydrolysis takes place and uy-dialdehydopopane- PP-dicarboxylic acid is produced. Apart from the method of synthesis the constitution of this acid is demonstrated by the facts that it is converted on reduction into bis-y-butyrolactone-aa-spiran (I) which Leuchs and Gieseler (Ber., 1912 44 2114) obtained by the action of ethylene bromoacetate on ethyl sodiomalonate and that on oxidation it yields propane-aPPy-tetracarboxylic acid (11) which a t its melting point is decom-posed with elimination of carbon dioxide and formation of tri-.carballylic acid (compare Bischoff Ber. 1896 29 267). Acid When ay-dialdehydopropane- PP-dicarboxylic acid is heated wi+h water a t 180" it is decomposed with elimination of carbon dioxide. and formation of ay-dialdehydolwolxtne- p-car~oxylic mid, CHO*CH,*CH( CO,H)*CH,*CHO. E X P E R I M E N T A L . Ethyl Dimetcclmalonate.-The ethyl acetalmalonate required for-the preparation of this substance was obtained by a d m g ethy 192 PERKIN AND PINK: malonate (100 9.) and bromoacetal (80 g.) to sodium (14.2 g.) dissolved in alcohol (200 c.c.).The mixture was heated in an autoclave fitted with a mechanical stirrer for 4 hours the temper-ature of the surrounding oil-bath being kept at 180". The product was worked up as described in the previous communication (J. 1899, 75 13) and the ester (72 g.) distilled a t 163-165"/20 mm. In the preparation of the diacetal derivative potassium (8 g.) is melted under boiling toluene (50 c.c.) pulverised by shaking cooled and ethyl acetalmalonate (55 9.) added very gradually. A vigorous action takes place and if the ester is added too rapidly the heat generated is sufficient to raise the toluene to the boiling point and the solution turns brown. When all the ethyl acetalmalonate has been introduced and the last traces of metal have disappeared bromo-acetal (40 g.) is added and four such portions are united and heated in the autoclave during 6 hours with constant stirring the temper-ature of the oil-bath being maintained a t 200".After standing over-night the product is transferred to flasks the toluene removed under reduced pressure the residue mixed with water and ether, the ethereal extract well washed dried over anhydrous potassium carbonate and the ether distilled off. The distillation is continued under reduced pressure when unchanged ethyl acetalmalonate (80 g.) comes over a t 140-170"/20 mm.; the thermometer then rises rapidly to 187" between which temperature and 200" the main portion of the ethyl diacetalmalonate passes over ; there is a further fraction a t 200-250" which has not been examined.On redis-tillation ethyl diacetalmalonate is obtained as a colourless rather viscid oil b. p. 192-196"/18 mm. dg 1.031 (Pound C = 58.3; H = 9.2. The ester (5 g.) was mixed with a methyl-alcoholic solution of barium hydroxide (32 C.C. of a solution of 16 g. of Ba(OH),,8H20 in 100 C.C. of methyl alcohol = 25% excess) and boiled on the steam-bath for 4 hours. Water (10 vols.) was then added the whole saturated with carbon dioxide and the filtrate from the barium carbonate concentrated on the steam-bath, but the salt did not crystallise On evaporation to dryness a pale yellow brittle salt remained which is moderately soluble in water (Found Ba = 31.0. C,,H,,O,Ba requires Ba = 29.1%). The powdered barium salt (5 g.) was mixed with a little water and slightly less than the calculated quantity (21 c.c.) of N-sulphuric acid added with vigorous stirring.After standing over-night the whole was filtered the filtrate extracted repeatedly with pure ether, the ethereal solution dried over anhydrous magnesium sulphate, and the ether allowed to evaporate when diacetalmalonic acid was left as a pale viscid syrup which showed no tendency to crystallise. C,,H2608 requires C = 58.2; H = 9.2%). Hydrolysis.-(i) By Alkali Cty-DIALDEHYDOPROPANE- PP-DICARBOXYLIC ACID ETC. 193 After remaining for 3 days in a vacuum desiccator over solid potassium hydroxide this was analysed (Found C = 53-3; H = 8.3. On titration with N/10-alcoholic potassium hydroxide 0.22 neutralised 0-0533 KOH whereas this amount of a dibasic acid C,5H2808 should neutralise 0-0524 KOH).(ii). By Concentrated Hydrochloric Acid. Ethyl diacetal-malonate (10 g.) was well shaken with concentrated hydrochloric acid (30 c.c.) when complete solution took place and after 24 hours, the rather dark liquid was diluted with water filtered from a little tarry matter and evaporated to a small bulk under reduced pressure the temperature not being allowed to rise above 30". After further evaporation over sulphuric acid in a vacuum desiccator, a pale brown syrup resulted and this was mixed with water and again evaporated the operation being repeated several times. The syrup remained as such for 7 weeks and then suddenly crystal-lised and the mass was drained on porous porcelain and crystallised from water from which it separated in colourless prisms (Found : C = 44.7; H = 4.5.C,H,06 requires C = 44.7; H = 4.3%). a y-Dialdehydopropane- PP-dicarboxylic acid melts a t 122" with decomposition and is readily soluble in water alcohol or acetone, sparingly so in ether and almost insoluble in petroleum benzene, chloroform or carbon tetrachloride. On titration 0,1562 neutra-lised 0.0665 NaOH whereas this amount of a dibasic acid C,H,O& should neutralise 0.0664 NaOH. A neutral solution of the ammon-ium salt gives with silver nitrate a white precipitate which rapidly darkens and silver is deposited. The di-p-nitrophenylhydrazone separated as a yellow crystalline precipitate when the aqueous solution of the acid (0.6 9.) was mixed with p-nitrophenylhydrazine (0.85 g.) dissolved in dilute acetic acid and separated from alcohol in glistening plates m.p. 156" (decomp.) (Found N = 18.2. C19H1808N6 requires N = 18.3%). The ethyl ester was obtained when ethyl diacetalmalonate (15 g.) was well shaken with N-hydrochloric acid (30 c.c.) and after remain-ing for 24 hours the whole was several times extracted with ether, the extract washed with sodium carbonate dried over potassium carbonate and distilled when the ester passed over a t 174-178"/18 rnm. The p-nitrophenylhydrazone prepared in dilute acetic acid solution crystallised from alcohol as a microcrystalline powder, m. p. 170" (Pound N = 16.2. C2,H,,O8N6 requires N = 16.3%). Reduction of ay-Dialdehydopropane-PP-dicarboxylic Acid.-The dibasic acid (4 g.) dissolved in water (75 c.c.) was mixed with sodium bicarbonate (15 g.) and treated with sodium amalgam (150 g.of 404,) in a flask fitted a-it5 a mechanical stirrer and cooled in ice the C,,H,,O requires C = 53.6; H = 8.3%. VOL. CXXVII. € 194 ay-DIALDEHYDOPROPANE- ~~-DICARBOXYLIC ACID ETC. reduction being complete in about 8 hours. The alkaline solution was acidified with dilute sulphuric acid (10 g.) in water (20 c.c.), concentrated on the steam-bath repeatedly extracted with chloro-form the extract dried over anhydrous magnesium sulphate and the chloroform allowed to evaporate. The colourless crystalline residue separated from water in plates m. p. 109-llO" and was evidently identical with bis- 7-butyrolactone-aor-spiran described by Leuchs and Gieseler (loc.cit.). Oxidation of ay-Dialdehydopropane- p p-dicarboxylic Acid.-The acid (5 g.) dissolved in water (20 c.c.) was mixed with potassium dichromate (5.2 g.) in sulphuric acid (6.9 g.) and water (75 c.c.) and allowed to stand for 12 hours during which the colour changed t o green. The product evaporated on the steam-bath to 50 c.c. was extracted with ether the extract dried over anhydrous magnesium sulphate and the ether allowed to evaporate over sulphuric acid. The oily residue remained for weeks without crystallising but did SO rapidly when a crystal of propane-appy-tetracarboxylic acid was introduced. After contact with porous porcelain the substance separated from ether in needles melted a t 151" with decomposition into carbon dioxide and tricarballylic acid and was thus identified with propane- @Py- tetracarboxylic acid.a y- Dialdehydopropane- p-carboxylic Acid .-This acid was obtained when ay-dialdehydopropane- pp-dicarboxylic acid (4 g . ) dissolved in water (16 c.c.) was heated in a sealed tube a t 180" for 4 hours. On opening the tube carbon dioxide escaped and the solution, evaporated in a vacuum over sulphuric acid deposited a syrup which even on long standing did not crystallise (Pound C = 49-5 ; H = 5.5. C6H804 requires C = 50.0; H = 5.5%). The di-p-nitrophenylhydraxone obtained by adding a solution of p-nitro-phenylhydrazine in dilute acetic acid to the aqueous solution of the acid and heating for an hour on the steam-bath is a yellow amor-phous powder sparingly soluble in the usual solvents.The substance could not be recrystallised and was pursed by extraction with hot alcohol and then with ether when the residue melted a t about 198" (decornp.) (Found N = 20.3. C,&,80$6 requires N = 21.3%). One of us (H. S. P.) desires to thank the Department of Scientific and Industrial Research for a maintenance grant and the Govern-ment Grant Committee of the Royal Society for a grant for materials. THE DYSON PERRINS LABORATORY, OXFORD. [Received November 12tl2 1924. ay-DIALDEHYDOPROPANE- p P-DICAEBOXYLIC ACID ETC. 19 1 X X X.-a y-Diald ehydopropane-PP-dicarbox ylic and a y -Dialdehydopropane-P-carbox ylic Acid. B y WILLIAM HENRY PERKIN jun. and HERBERT SHEPPARD PINK. THIS communication is a continuation of the work of Perkin and Sprankling (J.1899,75 1 l) who showed that ethyl acetalmalonate, obtained when ethyl sodiomalonate is heated with bromoacetal, yields on hydrolysis acetalmalonic acid and that this acid when heated with water at 180° loses carbon dioxide with the formation of P-aldehydopropionic acid : (EtO),CH*CH,*CH(CO,Et) -+ (EtQ),CH-CH,*CH(CO,H), -P CHO*CH,*CH,*CO,H. The oxidation of the latter acid to succinic acid its reduction to butyrolactone and its conversion into terephthalic acid by treat-ment with alkali were described. It is now shown that the potas-sium derivative of ethyl acetalmalonate reacts with bromoacetal with the formation of ethyl diacetalmalonate (A) and that this ester on hydrolysis with baryta yields diacetalmalonic acid, (Et O),CH *CH,=C( CO,H),*CH,*CH( OEt),.When the ester (A) is left in contact with N-hydrochloric acid in the cold it is converted into the ester of ay-dialdehydopropane-pp-dicarbozylic acid CHO*CH2*C(C0,Et),*CH2=CH0 but if concen-trated hydrochloric acid is employed further hydrolysis takes place and uy-dialdehydopopane- PP-dicarboxylic acid is produced. Apart from the method of synthesis the constitution of this acid is demonstrated by the facts that it is converted on reduction into bis-y-butyrolactone-aa-spiran (I) which Leuchs and Gieseler (Ber., 1912 44 2114) obtained by the action of ethylene bromoacetate on ethyl sodiomalonate and that on oxidation it yields propane-aPPy-tetracarboxylic acid (11) which a t its melting point is decom-posed with elimination of carbon dioxide and formation of tri-.carballylic acid (compare Bischoff Ber. 1896 29 267). Acid When ay-dialdehydopropane- PP-dicarboxylic acid is heated wi+h water a t 180" it is decomposed with elimination of carbon dioxide. and formation of ay-dialdehydolwolxtne- p-car~oxylic mid, CHO*CH,*CH( CO,H)*CH,*CHO. E X P E R I M E N T A L . Ethyl Dimetcclmalonate.-The ethyl acetalmalonate required for-the preparation of this substance was obtained by a d m g ethy 192 PERKIN AND PINK: malonate (100 9.) and bromoacetal (80 g.) to sodium (14.2 g.) dissolved in alcohol (200 c.c.). The mixture was heated in an autoclave fitted with a mechanical stirrer for 4 hours the temper-ature of the surrounding oil-bath being kept at 180". The product was worked up as described in the previous communication (J.1899, 75 13) and the ester (72 g.) distilled a t 163-165"/20 mm. In the preparation of the diacetal derivative potassium (8 g.) is melted under boiling toluene (50 c.c.) pulverised by shaking cooled and ethyl acetalmalonate (55 9.) added very gradually. A vigorous action takes place and if the ester is added too rapidly the heat generated is sufficient to raise the toluene to the boiling point and the solution turns brown. When all the ethyl acetalmalonate has been introduced and the last traces of metal have disappeared bromo-acetal (40 g.) is added and four such portions are united and heated in the autoclave during 6 hours with constant stirring the temper-ature of the oil-bath being maintained a t 200". After standing over-night the product is transferred to flasks the toluene removed under reduced pressure the residue mixed with water and ether, the ethereal extract well washed dried over anhydrous potassium carbonate and the ether distilled off.The distillation is continued under reduced pressure when unchanged ethyl acetalmalonate (80 g.) comes over a t 140-170"/20 mm.; the thermometer then rises rapidly to 187" between which temperature and 200" the main portion of the ethyl diacetalmalonate passes over ; there is a further fraction a t 200-250" which has not been examined. On redis-tillation ethyl diacetalmalonate is obtained as a colourless rather viscid oil b. p. 192-196"/18 mm. dg 1.031 (Pound C = 58.3; H = 9.2. The ester (5 g.) was mixed with a methyl-alcoholic solution of barium hydroxide (32 C.C.of a solution of 16 g. of Ba(OH),,8H20 in 100 C.C. of methyl alcohol = 25% excess) and boiled on the steam-bath for 4 hours. Water (10 vols.) was then added the whole saturated with carbon dioxide and the filtrate from the barium carbonate concentrated on the steam-bath, but the salt did not crystallise On evaporation to dryness a pale yellow brittle salt remained which is moderately soluble in water (Found Ba = 31.0. C,,H,,O,Ba requires Ba = 29.1%). The powdered barium salt (5 g.) was mixed with a little water and slightly less than the calculated quantity (21 c.c.) of N-sulphuric acid added with vigorous stirring. After standing over-night the whole was filtered the filtrate extracted repeatedly with pure ether, the ethereal solution dried over anhydrous magnesium sulphate, and the ether allowed to evaporate when diacetalmalonic acid was left as a pale viscid syrup which showed no tendency to crystallise.C,,H2608 requires C = 58.2; H = 9.2%). Hydrolysis.-(i) By Alkali Cty-DIALDEHYDOPROPANE- PP-DICARBOXYLIC ACID ETC. 193 After remaining for 3 days in a vacuum desiccator over solid potassium hydroxide this was analysed (Found C = 53-3; H = 8.3. On titration with N/10-alcoholic potassium hydroxide 0.22 neutralised 0-0533 KOH whereas this amount of a dibasic acid C,5H2808 should neutralise 0-0524 KOH). (ii). By Concentrated Hydrochloric Acid. Ethyl diacetal-malonate (10 g.) was well shaken with concentrated hydrochloric acid (30 c.c.) when complete solution took place and after 24 hours, the rather dark liquid was diluted with water filtered from a little tarry matter and evaporated to a small bulk under reduced pressure the temperature not being allowed to rise above 30".After further evaporation over sulphuric acid in a vacuum desiccator, a pale brown syrup resulted and this was mixed with water and again evaporated the operation being repeated several times. The syrup remained as such for 7 weeks and then suddenly crystal-lised and the mass was drained on porous porcelain and crystallised from water from which it separated in colourless prisms (Found : C = 44.7; H = 4.5. C,H,06 requires C = 44.7; H = 4.3%). a y-Dialdehydopropane- PP-dicarboxylic acid melts a t 122" with decomposition and is readily soluble in water alcohol or acetone, sparingly so in ether and almost insoluble in petroleum benzene, chloroform or carbon tetrachloride.On titration 0,1562 neutra-lised 0.0665 NaOH whereas this amount of a dibasic acid C,H,O& should neutralise 0.0664 NaOH. A neutral solution of the ammon-ium salt gives with silver nitrate a white precipitate which rapidly darkens and silver is deposited. The di-p-nitrophenylhydrazone separated as a yellow crystalline precipitate when the aqueous solution of the acid (0.6 9.) was mixed with p-nitrophenylhydrazine (0.85 g.) dissolved in dilute acetic acid and separated from alcohol in glistening plates m. p. 156" (decomp.) (Found N = 18.2. C19H1808N6 requires N = 18.3%). The ethyl ester was obtained when ethyl diacetalmalonate (15 g.) was well shaken with N-hydrochloric acid (30 c.c.) and after remain-ing for 24 hours the whole was several times extracted with ether, the extract washed with sodium carbonate dried over potassium carbonate and distilled when the ester passed over a t 174-178"/18 rnm.The p-nitrophenylhydrazone prepared in dilute acetic acid solution crystallised from alcohol as a microcrystalline powder, m. p. 170" (Pound N = 16.2. C2,H,,O8N6 requires N = 16.3%). Reduction of ay-Dialdehydopropane-PP-dicarboxylic Acid.-The dibasic acid (4 g.) dissolved in water (75 c.c.) was mixed with sodium bicarbonate (15 g.) and treated with sodium amalgam (150 g. of 404,) in a flask fitted a-it5 a mechanical stirrer and cooled in ice the C,,H,,O requires C = 53.6; H = 8.3%. VOL. CXXVII. € 194 ay-DIALDEHYDOPROPANE- ~~-DICARBOXYLIC ACID ETC.reduction being complete in about 8 hours. The alkaline solution was acidified with dilute sulphuric acid (10 g.) in water (20 c.c.), concentrated on the steam-bath repeatedly extracted with chloro-form the extract dried over anhydrous magnesium sulphate and the chloroform allowed to evaporate. The colourless crystalline residue separated from water in plates m. p. 109-llO" and was evidently identical with bis- 7-butyrolactone-aor-spiran described by Leuchs and Gieseler (loc. cit.). Oxidation of ay-Dialdehydopropane- p p-dicarboxylic Acid.-The acid (5 g.) dissolved in water (20 c.c.) was mixed with potassium dichromate (5.2 g.) in sulphuric acid (6.9 g.) and water (75 c.c.) and allowed to stand for 12 hours during which the colour changed t o green.The product evaporated on the steam-bath to 50 c.c. was extracted with ether the extract dried over anhydrous magnesium sulphate and the ether allowed to evaporate over sulphuric acid. The oily residue remained for weeks without crystallising but did SO rapidly when a crystal of propane-appy-tetracarboxylic acid was introduced. After contact with porous porcelain the substance separated from ether in needles melted a t 151" with decomposition into carbon dioxide and tricarballylic acid and was thus identified with propane- @Py- tetracarboxylic acid. a y- Dialdehydopropane- p-carboxylic Acid .-This acid was obtained when ay-dialdehydopropane- pp-dicarboxylic acid (4 g . ) dissolved in water (16 c.c.) was heated in a sealed tube a t 180" for 4 hours. On opening the tube carbon dioxide escaped and the solution, evaporated in a vacuum over sulphuric acid deposited a syrup which even on long standing did not crystallise (Pound C = 49-5 ; H = 5.5. C6H804 requires C = 50.0; H = 5.5%). The di-p-nitrophenylhydraxone obtained by adding a solution of p-nitro-phenylhydrazine in dilute acetic acid to the aqueous solution of the acid and heating for an hour on the steam-bath is a yellow amor-phous powder sparingly soluble in the usual solvents. The substance could not be recrystallised and was pursed by extraction with hot alcohol and then with ether when the residue melted a t about 198" (decornp.) (Found N = 20.3. C,&,80$6 requires N = 21.3%). One of us (H. S. P.) desires to thank the Department of Scientific and Industrial Research for a maintenance grant and the Govern-ment Grant Committee of the Royal Society for a grant for materials. THE DYSON PERRINS LABORATORY, OXFORD. [Received November 12tl2 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700191

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

NEW SYNTHESIS OF THE MECONINES. 195 XXXI. -New Synthesis of the Meconines. By GEORGE ALFRED EDWARDS WILLIAM HENRY PERKIN Sun. and FRANCIS WILBERT STOYLE. THIS communication is concerned with a new and direct method for the synthesis of meconine (I) and m-meconine (111) and an indirect one for that of +-meconine (11) since this substance is quite easily prepared from meconine. Me0 Me0 Meconine (I.) q-Meconine (11.) m-Meconine (111.) The direct substitution of the group -CH,*OH into the benzene nucleus has been carried out in a variety of ways. Benzene itself, when treated with s-dichlorodimethyl ether in presence of zinc chloride gives some benzyl chloride (Stephen Gladding and Short, J. 1920 117 570) whilst phenols and their ethers condense with formaldehyde in presence of cold aqueous alkali to yield the corre-sponding benzyl alcohols (Manasse Ber.1894 27 2411 ; Lederer, J . pr. Chem. 1894 [ii] 50 225). We have found that the veratric acids do not condense a t all readily either with s-dichlorodimethyl ether or with cold aqueous formaldehyde but on boiling with an excess of formaldehyde and concentrated hydrochloric acid the corresponding meconine is formed in moderately good yield accord-ing to the scheme Meconine which was originally prepared synthetically in very poor yield by the cpndensation of o-veratric acid with chloral (Fritsch Annulen 1898,301,51) has now been obtained in 25-30% yields by the above-mentioned method the formaldehyde unex-pectedly substituting entirely in the position ortho to the carboxyl group as was shown by the identity of the only product isolated with t,he substa,nce produced by the reduction of opianic acid (IV).Since meconine on oxidation with manganese dioxide and dilute sulphuric acid is converted into opianic acid (IV) this new synthesis of meconine is also a synthesis of opianic acid an acid which has not previously been obtained synthetically (compare Perkin and Fargher J. 1921 119 1724). It further provides a synthesis of H 196 EDWARDS PERKIN AND STOYLE : hemipinic acid since this substance is produced on oxidation with potassium permanganate . An indirect synthesis of +-meconine (11) is completed by convert-ing the hemipinic acid obtained as above into its anhydride, (MeO),C6H,<co>0 co by dehydration with acetyl chlotide and reducing the product with zinc dust and acetic acid (compare Salomon Ber.1887 20 889). Attempts to prepare $-opianic acid by oxidation of the q-meconine were all unsuccessful the acid fht formed being more easily oxidised than the q-meconine itself. Salomon (Zoc. cit.) states that he was unable to bring about this oxidation. m-Meconine (111) first obtained by Perkin (J. 1916 109 815) from the degradation products of cryptopine derivatives is similarly produced by the condensation of veratric acid with formaldehyde in presence of concentrated hydrochloric acid and the synthetic product is in every way identical with the m-meconine obtained by Perkin. The lactone ring of this substance is readily opened by alkalis and on neutralising the cooled solution of the resulting salt with acetic acid 4 5-dimethoxy-2-~a~rboxybenzyl alcohol (V) slowly separates.Strong mineral acids rapidly transform this into the lactone as does heating it to its melting point or boiling its aqueous solution. m-Opianic acid (VI) required in the laboratory for synthetic work is very difficult to obtain and it was hoped that it might be possible to prepare it from m-meconine by oxidation. But although treatment with manganese dioxide and dilute sulphuric acid yielded sufficient m-opianic acid for identification the method in its present form is valueless for the preparation of any quantity of material. On the other hand m-hemipinic acid in moderately good yield is obtained by the oxidation of m-meconine with alkaline per-manganate and this may prove the most convenient method for the preparation of this acid.Attempts were also made to obtain the metlhylene ether of 4 5-dihydroxyphthalide by the condensation of piperonylic acid with f~rma~ldehyde but even after long boiling most of the acid was recovered unchanged only a small yield of an easily oxidisable substance of high molecular weight being produced NEW SYNTHESIS OF THE MECONINES. 197 E X P E R I M E N T A L . 0- Veratric Acid.-The preparation of this acid by the oxidation of o-veratraldehyde was best carried out in the following way. The aldehyde (30 g.) was kept boiling under a reflux condenser with water (300 c.c.) and potassium bicarbonate (35 g.) while a hot solut'ioii of potassium permanganate (22 g.) in water was added slowly.The cooled and filtered soluticn on acidification yielded o-veratric acid m. p. 120-122". Meconine (I).-Veratric acid (10 g.) formaldehyde solution (26 C.C. of 40%) and concentrated hydrochloric acid (40 c.c.) were boiled together under reflux for 15-30 minutes when the solution had turned brown and a dark gum had separated. The hot solution was filtered cooled and diluted wit'h water when a mixture of meconine with unchanged acid crystallised out. The solid was washed with sodium carbonate solution to remove the acid and the meconine (2.5-3 g.) was crystallised from hot water being obtained in colourless prisms m. p. 102". Its identity with the product of the reduction of opianic acid with sodium amalgam was shown by a variety of methods (Pound C = 62.0; H = 5.2.Calc. for Cl0HI0O4 C = 61.6; H = 5.1%). Opianic Acid (IV).-Meconine (3 g.) was boiled for 3 hours under reflux with dilute sulphuric acid (50 C.C. of 20% solution) and finely powdered manganese dioxide (10 g.). The result'ing solution on cooling and standing deposited crystals of opianic acid in a prac-tically pure state and in nearly theoretical yield. After a further recrystallisation from hot water the acid was obtained as colourless prisms m. p. 146". It was shown to be identical in every respect with the opianic acid obtained by the oxidation of narcotine with manganese dioxide (Found C = 57.2; H = 4.9. Calc. for CloHloO, C = 57-1; H = 4.8%). Hemipinic Acid.-This acid was best obtained as follows. Opianic acid (10 g.) water (100 c.c.) and lead dioxide (30 g.) were kept a t 100" on a water-bath while dilute sulphuric acid was slowly run in.When the evolution of carbon dioxide became rapid the mixture was cooled a little more sulphuric acid added the solution filtered from lead sulphate and excess lead dioxide and evaporated to small bulk. The hemipinic acid separated on cooling in a hydrated crystalline state and the anhydrous acid was obtained by heating it a t 100" for some time. The amorphous product (7-8 g.) melted a t 177". Hemipinic anhydride is most conveniently prepared as follows. The acid is heated under reflux with excess of acetyl chloride for 1 hour when the solution is evaporated to small bulk and th 198 NEW SYNTHESIS OX THE MECONINES. anhydride allowed to crystallise from the residue.It is thus obtained as glistening needles m. p. 168". 'Verutric acid the preparation of which is not apparently, described in detail in the literature is best obtained by slowly adding potassium permanganate (34 g.) in warm water to a con-stantly stirred mixture of veratraldehyde and water (50 g. in 300 c.c.) kept a t 50-60" a current of carbon dioxide being passed through the solution the whole time. The filtered and cooled solution is extracted with ether to remove any unchanged aldehyde and the product thrown out by acidification. Veratric acid (50 g.) is thus obtained in a nearly pure semi-gelatinous state and without further purification melts at 179". m-Meconine.-Veratric acid (50 g.) was heated on a water-bath for 12 hours with formaldehyde (55 C.C.of 40% solution) and con-centrated hydrochloric acid (200 c.c.). The product was cooled rapidly diluted with its own bulk of water and shaken violently until the emulsion formed deposited a gummy substance on the walls of the vessel leaving a clear solution. The latter after being filtered and allowed to stand slowly deposited m-meconine (9-15 g.) as a brown crystalline powder. After washing with sodium carbonate solution it was recrystallised from dilute alcohol when it separated as colourless needles m. p. 155-157". It was identical with the substance obtained by Perkin (Zoc. cit.) by the reduction of m-opianic acid with sodium amalgam. Further quantities of the lactone were obtained by extracting the resinous substance left clinging to the walls of the reaction vessel with hot caustic soda solution boiling the filtrate with animal charcoal and acidifying with hydrochloric acid.The substance which separated on standing recrystallised from aqueous alcohol with a brown colour but melted at the same temperature as the colourless crystals (Found C = 61.7; H = 5.0. Calc. for CloHloO, C = 61.8; H = 5.1%). 4 5-Dimethoxy-2-carboxybenzyl Alcohol (V) .-rn-Meconine was dissolved in the minimum amount of hot caustic soda solution and the cooled product was just acidified with acetic acid. On standing, the hydroxy-acid separated as clusters of minute needles melting indefinitely at 146-149". The product is very much more soluble in water than m-meconine; but if the solution is kept boiling for a short time m-meconine separates as h e needles.Oxidation of m-Meconine.-m-Meconine was boiled for 4 hours with manganese dioxide and dilute sulphuric acid in the same proportions as those used in the oxidation of meconine. On filtering and cooling the product about one-third of the m-meconine separated unchanged. The mother-liquor after being mad THE REDUCTION POTENTIALS OF QUINHYDRONES. 199 alkaline with sodium carbonate was fdtered and the manganese in solution was thus removed as carbonate. The acidified solution was evaporated to dryness in a vacuum the dry residue extracted with boiling absolute alcohol and the solution evaporated. The product was taken up in a little boiling water and one or two drops of phenylhydrazine were added. After the solution had boiled for a short time the phenylhydrazone of m-opianic acid separated as white flocks and after recrystallisation from alcohol became colourless at 173-176" and melted at 228".This behaviour was shown by Perkin and Fargher (J.? 1921 119 1743) to be character-istic of m-opianic acid and a mixed melting point with some of the phenyl-m-opiazone (m. p. 228") prepared by them established the identity. m-Hemipinic Acid.-A solution of m-meconine in a slight excess of aqueous caustic soda was saturated with carbon dioxide and a little sodium bicarbonate added. The calculated amount of potassium permanganate for the oxidation having been added, the mixture was heated on the water-bath until the colour of the permanganate had been removed a current of carbon dioxide being passed through the whole time.The filtered and acidified solution was evaporated to small bulk and the resulting liquid deposited m-hemipinic acid as yellow crystals m. p. 203" (decomp.). This was shown to be identical with the acid obtained by Perkin and Fargher (Eoc. cit.). Two of us (G. A. E. and F. W. S.) desire to thank the Department of Scientific and Industrial Research for grants which enabled us to take part in this research and one of us (F. W. 8.) thanks the Royal Society for a grant which defrayed part of its expense. THE DYSON PERRINS LABORATORY, OXFORD. [Received November 7th 1924. NEW SYNTHESIS OF THE MECONINES. 195 XXXI. -New Synthesis of the Meconines. By GEORGE ALFRED EDWARDS WILLIAM HENRY PERKIN Sun. and FRANCIS WILBERT STOYLE.THIS communication is concerned with a new and direct method for the synthesis of meconine (I) and m-meconine (111) and an indirect one for that of +-meconine (11) since this substance is quite easily prepared from meconine. Me0 Me0 Meconine (I.) q-Meconine (11.) m-Meconine (111.) The direct substitution of the group -CH,*OH into the benzene nucleus has been carried out in a variety of ways. Benzene itself, when treated with s-dichlorodimethyl ether in presence of zinc chloride gives some benzyl chloride (Stephen Gladding and Short, J. 1920 117 570) whilst phenols and their ethers condense with formaldehyde in presence of cold aqueous alkali to yield the corre-sponding benzyl alcohols (Manasse Ber. 1894 27 2411 ; Lederer, J . pr. Chem. 1894 [ii] 50 225).We have found that the veratric acids do not condense a t all readily either with s-dichlorodimethyl ether or with cold aqueous formaldehyde but on boiling with an excess of formaldehyde and concentrated hydrochloric acid the corresponding meconine is formed in moderately good yield accord-ing to the scheme Meconine which was originally prepared synthetically in very poor yield by the cpndensation of o-veratric acid with chloral (Fritsch Annulen 1898,301,51) has now been obtained in 25-30% yields by the above-mentioned method the formaldehyde unex-pectedly substituting entirely in the position ortho to the carboxyl group as was shown by the identity of the only product isolated with t,he substa,nce produced by the reduction of opianic acid (IV). Since meconine on oxidation with manganese dioxide and dilute sulphuric acid is converted into opianic acid (IV) this new synthesis of meconine is also a synthesis of opianic acid an acid which has not previously been obtained synthetically (compare Perkin and Fargher J.1921 119 1724). It further provides a synthesis of H 196 EDWARDS PERKIN AND STOYLE : hemipinic acid since this substance is produced on oxidation with potassium permanganate . An indirect synthesis of +-meconine (11) is completed by convert-ing the hemipinic acid obtained as above into its anhydride, (MeO),C6H,<co>0 co by dehydration with acetyl chlotide and reducing the product with zinc dust and acetic acid (compare Salomon Ber. 1887 20 889). Attempts to prepare $-opianic acid by oxidation of the q-meconine were all unsuccessful the acid fht formed being more easily oxidised than the q-meconine itself.Salomon (Zoc. cit.) states that he was unable to bring about this oxidation. m-Meconine (111) first obtained by Perkin (J. 1916 109 815) from the degradation products of cryptopine derivatives is similarly produced by the condensation of veratric acid with formaldehyde in presence of concentrated hydrochloric acid and the synthetic product is in every way identical with the m-meconine obtained by Perkin. The lactone ring of this substance is readily opened by alkalis and on neutralising the cooled solution of the resulting salt with acetic acid 4 5-dimethoxy-2-~a~rboxybenzyl alcohol (V) slowly separates. Strong mineral acids rapidly transform this into the lactone as does heating it to its melting point or boiling its aqueous solution.m-Opianic acid (VI) required in the laboratory for synthetic work is very difficult to obtain and it was hoped that it might be possible to prepare it from m-meconine by oxidation. But although treatment with manganese dioxide and dilute sulphuric acid yielded sufficient m-opianic acid for identification the method in its present form is valueless for the preparation of any quantity of material. On the other hand m-hemipinic acid in moderately good yield is obtained by the oxidation of m-meconine with alkaline per-manganate and this may prove the most convenient method for the preparation of this acid. Attempts were also made to obtain the metlhylene ether of 4 5-dihydroxyphthalide by the condensation of piperonylic acid with f~rma~ldehyde but even after long boiling most of the acid was recovered unchanged only a small yield of an easily oxidisable substance of high molecular weight being produced NEW SYNTHESIS OF THE MECONINES.197 E X P E R I M E N T A L . 0- Veratric Acid.-The preparation of this acid by the oxidation of o-veratraldehyde was best carried out in the following way. The aldehyde (30 g.) was kept boiling under a reflux condenser with water (300 c.c.) and potassium bicarbonate (35 g.) while a hot solut'ioii of potassium permanganate (22 g.) in water was added slowly. The cooled and filtered soluticn on acidification yielded o-veratric acid m. p. 120-122". Meconine (I).-Veratric acid (10 g.) formaldehyde solution (26 C.C.of 40%) and concentrated hydrochloric acid (40 c.c.) were boiled together under reflux for 15-30 minutes when the solution had turned brown and a dark gum had separated. The hot solution was filtered cooled and diluted wit'h water when a mixture of meconine with unchanged acid crystallised out. The solid was washed with sodium carbonate solution to remove the acid and the meconine (2.5-3 g.) was crystallised from hot water being obtained in colourless prisms m. p. 102". Its identity with the product of the reduction of opianic acid with sodium amalgam was shown by a variety of methods (Pound C = 62.0; H = 5.2. Calc. for Cl0HI0O4 C = 61.6; H = 5.1%). Opianic Acid (IV).-Meconine (3 g.) was boiled for 3 hours under reflux with dilute sulphuric acid (50 C.C.of 20% solution) and finely powdered manganese dioxide (10 g.). The result'ing solution on cooling and standing deposited crystals of opianic acid in a prac-tically pure state and in nearly theoretical yield. After a further recrystallisation from hot water the acid was obtained as colourless prisms m. p. 146". It was shown to be identical in every respect with the opianic acid obtained by the oxidation of narcotine with manganese dioxide (Found C = 57.2; H = 4.9. Calc. for CloHloO, C = 57-1; H = 4.8%). Hemipinic Acid.-This acid was best obtained as follows. Opianic acid (10 g.) water (100 c.c.) and lead dioxide (30 g.) were kept a t 100" on a water-bath while dilute sulphuric acid was slowly run in. When the evolution of carbon dioxide became rapid the mixture was cooled a little more sulphuric acid added the solution filtered from lead sulphate and excess lead dioxide and evaporated to small bulk.The hemipinic acid separated on cooling in a hydrated crystalline state and the anhydrous acid was obtained by heating it a t 100" for some time. The amorphous product (7-8 g.) melted a t 177". Hemipinic anhydride is most conveniently prepared as follows. The acid is heated under reflux with excess of acetyl chloride for 1 hour when the solution is evaporated to small bulk and th 198 NEW SYNTHESIS OX THE MECONINES. anhydride allowed to crystallise from the residue. It is thus obtained as glistening needles m. p. 168". 'Verutric acid the preparation of which is not apparently, described in detail in the literature is best obtained by slowly adding potassium permanganate (34 g.) in warm water to a con-stantly stirred mixture of veratraldehyde and water (50 g.in 300 c.c.) kept a t 50-60" a current of carbon dioxide being passed through the solution the whole time. The filtered and cooled solution is extracted with ether to remove any unchanged aldehyde and the product thrown out by acidification. Veratric acid (50 g.) is thus obtained in a nearly pure semi-gelatinous state and without further purification melts at 179". m-Meconine.-Veratric acid (50 g.) was heated on a water-bath for 12 hours with formaldehyde (55 C.C. of 40% solution) and con-centrated hydrochloric acid (200 c.c.). The product was cooled rapidly diluted with its own bulk of water and shaken violently until the emulsion formed deposited a gummy substance on the walls of the vessel leaving a clear solution.The latter after being filtered and allowed to stand slowly deposited m-meconine (9-15 g.) as a brown crystalline powder. After washing with sodium carbonate solution it was recrystallised from dilute alcohol when it separated as colourless needles m. p. 155-157". It was identical with the substance obtained by Perkin (Zoc. cit.) by the reduction of m-opianic acid with sodium amalgam. Further quantities of the lactone were obtained by extracting the resinous substance left clinging to the walls of the reaction vessel with hot caustic soda solution boiling the filtrate with animal charcoal and acidifying with hydrochloric acid. The substance which separated on standing recrystallised from aqueous alcohol with a brown colour but melted at the same temperature as the colourless crystals (Found C = 61.7; H = 5.0.Calc. for CloHloO, C = 61.8; H = 5.1%). 4 5-Dimethoxy-2-carboxybenzyl Alcohol (V) .-rn-Meconine was dissolved in the minimum amount of hot caustic soda solution and the cooled product was just acidified with acetic acid. On standing, the hydroxy-acid separated as clusters of minute needles melting indefinitely at 146-149". The product is very much more soluble in water than m-meconine; but if the solution is kept boiling for a short time m-meconine separates as h e needles. Oxidation of m-Meconine.-m-Meconine was boiled for 4 hours with manganese dioxide and dilute sulphuric acid in the same proportions as those used in the oxidation of meconine.On filtering and cooling the product about one-third of the m-meconine separated unchanged. The mother-liquor after being mad THE REDUCTION POTENTIALS OF QUINHYDRONES. 199 alkaline with sodium carbonate was fdtered and the manganese in solution was thus removed as carbonate. The acidified solution was evaporated to dryness in a vacuum the dry residue extracted with boiling absolute alcohol and the solution evaporated. The product was taken up in a little boiling water and one or two drops of phenylhydrazine were added. After the solution had boiled for a short time the phenylhydrazone of m-opianic acid separated as white flocks and after recrystallisation from alcohol became colourless at 173-176" and melted at 228".This behaviour was shown by Perkin and Fargher (J.? 1921 119 1743) to be character-istic of m-opianic acid and a mixed melting point with some of the phenyl-m-opiazone (m. p. 228") prepared by them established the identity. m-Hemipinic Acid.-A solution of m-meconine in a slight excess of aqueous caustic soda was saturated with carbon dioxide and a little sodium bicarbonate added. The calculated amount of potassium permanganate for the oxidation having been added, the mixture was heated on the water-bath until the colour of the permanganate had been removed a current of carbon dioxide being passed through the whole time. The filtered and acidified solution was evaporated to small bulk and the resulting liquid deposited m-hemipinic acid as yellow crystals m. p. 203" (decomp.). This was shown to be identical with the acid obtained by Perkin and Fargher (Eoc. cit.). Two of us (G. A. E. and F. W. S.) desire to thank the Department of Scientific and Industrial Research for grants which enabled us to take part in this research and one of us (F. W. 8.) thanks the Royal Society for a grant which defrayed part of its expense. THE DYSON PERRINS LABORATORY, OXFORD. [Received November 7th 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700195

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

THE REDUCTION POTENTIALS OF QUINHYDRONES. 199 XXXII. -Method of Measuring the Reduction Potentia'ls of Quinh ydrones. By EINAR BIILMANN A. LANGSETH JENSEN and KAI 0. PEDERSEN. IT has been pointed out by one of us (Trans. Faraduy Xoc. 1923, 19 676) that the reduction potential of a quinhydrone can be determined by measuring the potential of an electrode containing, for instance the hydroquinone of one quinhydrone in a solution of the quinone of another quinhydrone with a known reduction potential, that is without preparing the quinhydrone itself or both its con 200 BIILMANN JENSEN AND PEDERSEN METHOD OF (a) Pt I (a ; electrolyte ; (AYAH,) stituents. In this paper the theory of the method is described and some quantitative results are detailed. Let A AH, and (A,AH,) be a certain quinone hydroquinone, and quinhydrone respectively and let By BH, and (B,BH,) be another similar series.Then if a solution of the hydroquinone, AH, be mixed with a solution of the quinone By AH will be partly oxidised to the quinone A a t the expense of By which will be partly reduced to its corresponding hydroquinone BH,. Starting with equimolecular quantities of AH and By the reaction may be written aAH + aB + (a - x)AH + xA + (a - x)B + xBH . (1) and the equilibrium set up must be such that the reduction potential T (as measured against a hydrogen electrode) of the mixture (a - x)AH + xA is equal to the reduction potential of the mixture (a - x)B + xBH,. We have now four electrolytic chains to consider Pt Pt I c " l ~ y ~ ~ B ; electrolyte ; (B,BH,) ( b ) the similar chain Pt RT a - x - X += __ nF .loge- X - - K log10 rx (3) so that 4 = - +'; ( c ) the quinhydrone electrode with the reduction potential xof ; and ( d ) the quinhydrone electrode with the reduction potential xo.Pt 1 (A,AH,) ; H I Pt Pt I (BYBH,) ; H I Pt x = x o f - + = x o + + z.e. nof = 2ic -Tco=2++xo . . . (4) Now for equilibrium we must have where x is the voltage both of the chain (a - x) . mAH PtI x.mA i H 2 I P t and of the chai MEASURING THE REDUCTION POTENTIALS OF QUINHYDRONES. 201 That is to say the reduction potential no' of the quinhydrone (i) the potential X of a mixture of the hydroquinone AH with an equimolecular quantity of the quinone B (or conversely) to a hydrogen electrode. or (ii) the potential #, of this mixture to the quinhydrone electrode (A,AH,) can be determined by measuring (B,BH,).0.75 0.70 0.65 0.60 2 \ N <A I-In both cases we require to know the reduction potential no, of the quinhydrone (B,BH,) electrode; and obviously the electro lyte the temperature and the hydrogen pressure (1 atm.) must be the same in all the electrodes. Combining equations (3) and (4) we get no' - = 2+ = 2K log,(){x/(a - x)) = (at 25') 0.0591 log,,{x/(a - x)), from which equation x may be calculated when no and xo' have been determined. Taking the reduction potentials at 25" for benzoquinhydrone, toluquinhydrone and p-xyloquinhydrone as 0.6990 0-6454 and H 202 BIILMANN JENSEN AND PEDERSEN METHOD OF 0.5886 volt respectively the following values for the percentage of quinhydrone unchanged in equimolecular mixtures with quinones are obtained : yo Hydroquinone 12.4 1.4 Mixture.unchanged. Benzoquinone + Toluhydroquinone . . . . . . . . . Benzoquinone + p-Xylohydroquinone . . . . . Toluquinone + p-Xylohydroquinone . . . . . . 9.1 Two sources of error must be briefly mentioned. First the position of the equilibrium markedly affects the accuracy attain-able. Fig. 1 shows the relation between the composition of the solution and the potential referred to a hydrogen electrode at 25". Thus p denotes the potential (0.72 volt) of a mixture of 18-5y0 of benzohydroquinone and 8l.5yO of benzoquinone. Similarly A B, and C denote the potentials of the three quinhydrones. Now the potential of the equilibrium mixture of toluhydroquinone and benzoquinone is given by point a (the intersection of the corre-sponding curves) and it is obvious from the figure that the farther this point is removed from the centre line ABC the more rapidly will the potential change with composition and the less accurate will be the results.The second source of error is due to the inequality of the dis-sociation constants * of the various quinhydrones. At 25" the dissociation constant of benzoquinhydrone is 0.224 whilst for toluquinhydrone it is 0.095 (Biilmann Ann. Chim. 1921 [ix] 15, 151). But by comparing the values obtained by the " mixture " method with those obtained directly by La Mer ( J . Arner Chem. SOC. 1922 44 1954) and one of us (Biilmann Zoc. cit.) and also in this research it is seen that satisfactory agreement is obtained, * Let the initial concentrations of A and BH be a and the stoicheio.metric amounts of the quinones and hydroquinones a t equilibrium (as assumed in equation 1) be AH, a - x; A x ; BH, x; and By a - x. If the concentrations of undissociated quinhydrones AH,,A and BH,,B are a and p respectively the concentrations of the dissociated components will be AH, a - 1 - a; A x - a; BH, x - p ; and B a - x - /3. In the equilibrium set up the potentials of the mixtures of A and AH and of B and BH against the corresponding two quinhydrones are (equation 2) $A =K1ogl,a - - a a - x - / I If as supposed T,' - T = 2$ we have c p ~ = $B and consequently, (x - .)/(a - x - a) = (x - P)/(a - x - /3) or 2x(a - /3) = a(.- p). Consequently the supposed relation between the potential of the mixture and the reduction potentials of the single quinhydrones is strictly exact if a = /3 Le. the two quinhydrones have the same dissociation constants [as kA = (x - a)(o x - a)/u; kB = (z /?)(a - z - /3)//3] or if x = a / 2 , Le. their reduction potentials are identical. - ' respectively. x - a and $B = K log, MEASURING THE REDUCTION POTENTIALS OF QUINHYDRONES. 203 especially when the sparing solubility of the materials dealt with is considered. I n some cases the equilibrium potential was reached almost instantaneously; in others it was necessary to wait for some hours before measurement. Table I records the experimental results. TABLE I. Reduction Potentids of Quinhydrones.?ro measured in raisture. At 18". At 25". 0.6496 0.6444 - 0.5893 0.7178 0.7124 0.7174 0.7120 0.7280 0.7230 0.7280 0.7228 - 0.ti.542 - 0.65ti4 - 0.5949 * Biilmann Zoc. cit. t La Mer loc. Other deter-minations of ro at 25'. 0.6454 * 0.5886 0.7125 t 0.7151 t --0.6566 0.659 1 0.59 18 c i t . E Y P E R I M E N T A L. Toluhydroguinon e.-The t oluh ydroquin one was recryst allised from toluene immediately before the solution was made up. Equal volumes of 0.0 141-solutions of toluhydroquinone and benzoquinone in 0-liV-hydrochloric acid were mixed and the potentials measured against a benzoquinhydrone electrode blank platinum electrodes being used. TABLE 11. - p t I Toluhydroquinone 0*005A" ; ::& ; Benzoquinhydrone I Pt + Benzoquinone 0-00dJ1 254".18". Temp. 7- - Minutes ............ 30 60 150 180 Volt I * ............ 0.0273 0.0273 0.0274 0.0274 .. I1 * ......... 0.0274 0.0274 0.0275 0.0275 ~ z j " = 0.6444. r 1 3 = = 0.6496. * Duplicate electrodes. p-SyZohydro~~inoize.-The potentials were measured as above, but the electrolyte was 0.lK-sulphuric acid saturated with carbon dioxide and all the operations were carried out in an atmosphere of this gas. H* 204 BIILMANN JENSEN AND PEDERSEN METHOD OF 25.4". Temp. r- .J \__ - .-Minutes 25 60 106 135 165 195 1200 1290 1460 Volt I 0-0689 0.0775 0.0802 0.0809 0.0811 0-0813 0.0820 0.0821 0.0821 0.0702 0.0773 0.0792 0-0803 0.0807 0.0810 0.0822 0.0822 0.0823 , I1 1~25" = 0.5893. Solution prepared from equimolecular quantities of p-xylohydro-quinone and p-xyloquinone in 0-1N-sulphuric acid with carbon dioxide treatment as before.TABLE IV. 25.6". 18". Temp. A ,-'-, Minutes ......... 5 45 95 145 185 3 85 Volt I ......... 0.1101 0.1104 0-1104 0.1104 0-1103 0-1104 ,) I1 ......... 0.1102 0.1105 0.1105 0.1105 0.1105 0.1106 7250 = 0.5886. p1g = 0.5940. f Without the carbon dioxide treatment constant potentials could not be obtained. The potentials measured against the benzoquinhydrone electrode of a similar electrode prepared wit'h-out the carbon dioxide treatment are recorded in Table V and it will be seen that the potentials slowly rise until after 20 hours, they are practically identical with those in Table IV. This may be due to catalytic oxidation of the hydroquinone on the surface of the platinum the potential reaching the value in Table IV only when the solution in the electrode vessel is thoroughly mixed by diffusion.TABLE V. 25.4'. Temp. / A \ Minutes ......... 15 60 120 150 1120 1270 Volt I ......... 0.1072 0.1090 0.1099 0.1100 0.1101 0.1101 .. I1 ......... 0.1070 0.1093 0-1098 0.1099 0.1103 0.1103 MonochZorohydroquinone.-Benzoquinone (10 g.) was heated with 100 C.C. of concentrated hydrochloric acid for 2 hour on the steam-bath (Wohler AnnaZen 1844 51 155) the solution cooled, diluted with water and extracted with ether. The residue after evaporation of the ether had m. p. 103" when crystallised twice from chloroform and 105-105.5" (constant) when crystallised TWO = 0.5888 MEASURING THE REDUCTION POTENTIALS OF QUINHYDRONES.205 subsequently from carbon tetrachloride. Levy and Schultz quote 106" (ibid. 1881 210 138) and Schultz quotes 103-104" (Ber., 1882 15 654). TABLE VI. - Pt Benzoquinhyclrone HC1 . Monochlorohydroquinone 0.005M 1 Pt + 0.1N ' Benzoquinone 0.005M 23.4". 18". Temp. e- - F ,----. 18O.* Minutes ......... 15 30 60 120 180 Volt 1 ......... 0.0068 O*OOGS 0.0068 0.0067 0.0067 0.0006 , I1 ......... 0.0067 0.0067 0.0067 O*OOGG 0.0066 0.0066 * After dilution with 3 vols. of O.lX-HC1. A2j" = 0.7124. q g = 0.7178. Jlonobromohydroquinone was prepared after Sarauw's method (dnm,Zen 1881 209 105). Bromine (16 g.) in 100 C.C. of ether was added to 11 g. of hydroquinone in 259 C.C. of ether and the solution allowed to evaporate a t laboratory temperature.The residue was extracted with 260 C.C. of toluene at 90-95" filtered off and cooled. Recrystallised from 100 C.C. of toluene 5 g. gave 3.8 g. m. p. 110.5" unchanged by further recrystallisation. Yield 10 g. m. p. 109.8". Sarauw quotes m. p. 110-111". TABLE VII. - pt 1 Benzoquinhydrone ; HC1 . R'onobromoh~dro~uinone~ 0*05M pt + 0-1N ' Benzoquinone 0.05X 23.4". 1 SO. 150.* Temp. .-*-- 7.7 ,-I---. bIinutes ...... 15 30 5 5 so 125 15 55 Volt I ...... 0.0008 0.0005 0.0063 0.0065 0.0065 0.0063 O.OOci3, , I1 ...... 0.0068 0.0083 0.0065 0.0065 0.0065 0.0064 0.00G4, * After dilution with 3 vols. of O.1N-HCI. ~ 2 ~ ' = 0.7120. p l y " = 0.7174. 2 5-DichZorohydroqui~~o~~e.-Prepared by Ling's method (J., 1S92 61 65S) and twice crystallised from water the substance had a constant m.p. 169-170". Ling quotes 172" and Levy and Schultz (Zoc. cit.) 166". TABLE VIII. - Benzoquinhydrone HC1 . Dichlorohydroquinone O.OO25M j Pt + 0.1N ' Benzoquinone 0.0025111 25.4". 18". Temp. /- - 7'\7 1 )so.* Minutes . . . . . . . . . . . . . . . 15 30 90 150 T'olt I ............... 0.0121 0.0120 0~011s 0.0118 0.0117 . I1 ............... 0.0120 0.0120 0.0118 0.0118 0.0117 ~ 2 5 ~ == 0.7230. = 0.7280. * After dilution with 3 vols. ol 0-1N-HCI. 2 5-Dibromohydroquinone.-Prepared by the method of Beiiedict (No12cwtsh. 1880 1 345) and of Sarauw (Zoc. cit.) and twice crystal 206 BIILMANN JENSEN AND PEDERSEN METHOD OF lised from water the compound had the m. p. 186" recorded by those investigators. TABLE IX. Bemohydroquinone ; HC1 .Dibromohydroquinone 0.001M 0-1N ' Benzoquinone 0.001M 25.4'. 18". Temp. & - Minutes ............... 30 60 90 120 Volt I ............... 0.0119 0.0119 0.0119 0.0119 , I1 ............... 0.0119 0.0119 0.0117 0.0117 T ~ O = 0.7228. ~ 1 8 0 = 0.7280. Monochloroto1uhydroquinone.-Prepared by Schniter's method (Ber. 1887 20 2282) and crystallised from toluene and then twice from chloroform the product had m. p. 172-174" (uncorr.). Schniter quotes m. p. 175" [0.2048 reduced 26.0 C.C. of 0-1002N-iodine corresponding to 10043~o of C,H&eCl(OH),. C1 found = 22.26; calc. = 22.26%]. The hydrochloric acid used in the measurements was aerated with carbon dioxide. TABLE X. 25". r \ Temp. 1-Minutes ......... 10 40 100 150 175 1380 Volt I .. . . . . . . 0.0217 0.0220 0.0222 0.0222 0-0223 0.0225 , I1 ......... 0.0214 0.0219 0.0223 0.0226 0.0227 0.0229 Mean = 0.0224 ~ 2 5 . = 0.6542. Dichloroto1uquinhydrone.-Prepared by oxidising the correspond-ing hydroquinone in 50% alcohol with the calculated quantity of ferric ammonium alum. TABLE XI. -Pt I Dichlorotoluquinhydrone ; 0-1N-HCI ; Benzoquinhydrone 1 Pt + Temp. // \ 25". Minutes ...... 30 60 100 128 175 210 1110 1225 Volt I ...... 0.0394 0-0400 0.0406 0-0410 0.0415 0-0418 0.0425 0.0424 , I1 ...... 0-0382 0.0397 0*0400 0.0404 0-0407 0.0410 0.0424 0-0424 , I11 ...... 0.0382 0.0399 0*0400 0.0404 0.0408 0.0410 0.0424 0.0423 ~ 2 6 0 = 0.6566. TABLE XII. .-Pt I Dichlorotoluquinhydrone 0.00052cI ; 0-IN-HCI ; Benzoquinhydrone I Pt + 18". Temp.-- -'.- - -___ -\ Minutes 20 Volt I ..................... 0.0419 0.0419 0.04 19 , I1 .................. 0.0419 0.0419 0.04 19 , I11 ........... . ...... 0.0419 0.04 19 0.04 19 . . . . . . . . . . . . . . . . . . 30 45 ~ 1 8 0 = 0.6625 MEASURING THE REDUCTION POTENTIALS OF QUINHYDRONES. 207 Il/lonobromotoluhydroquinone.-To 5 g. of toluhydroquinone in 100 C.C. of ether and 45 C.C. of chloroform were added 6.45 g. of bromine in 82 C.C. of chloroform. The product (64 g.) recrystal-lised twice from toluene melted at 176-178". Clark (Amer. Chem. J . 1892 14 569) quotes 176-179". TABLE XIII. - '~.ionobromotoluh~dro~uinonc~ o.oo25nf ; ::& ; Bcnzoquinhr-drontl l>t + l'tlBenzoquinone 0.b023111 23". Temp. /-- - \---Minutes ............... 15 70 185 235 5lV Volt I ...............0.0209 0.0210 0.0212 0.0213 0.0214 .. I1 ............... 0.0205 0.020G 0.0208 0*0208 0.0213 Dibromoto1uquinhydrone.-Prepared by oxidising 1 g. of mono-bromotoluhydroquinone in 5 C.C. of alcohol with 12.25 c.c=. of O.2M-ferric ammonium alum the product was washed with water and dried between filter-paper (0.2003 titrated in presence of sodium bicarbonate with 0-0849N-iodine required 11-75 C.C. Mono-bromotoluhydroquinone = 50-3yu ; calc. 50.0%). 1~250 = 0.6564. TABLE XIV -Pt IDibromotoluquinhydrone 0.00125M ; HC10.1N ; Benzoquinhydroml Pt + Temp. / -. Volt I ............... 0-0397 0.0399 0.0399 0.0399 25.2". Minutes ............... 30 90 120 1.55 , I1 ............... 0.0397 0-0399 0.0399 0.0399 "'73" = 0,6591. ,MonochloroxyZohydroquinone.-Prepared by the method of v.Kad (Annulen 1869 151 166) and Carstanjen ( J . p. Chem. 1881, 23 430). 20 G. of p-xyloquinone were added to 200 C.C. of cold concentrated hydrochloric acid a further 300 C.C. of acid were added and the mixture was heated for 2-3 hours on the steam-bath. The crystals obtained on cooling were recrystallised from toluene carbon tetrachloride and twice from chloroform. Yield 7-75 g. m. p. 132-153" (Cl found 20.81 calc. 20.56%). TABLE XV. - pt M~nochlorox~loh~dro~uinone~ o.oo2Af ; zyb ; Benzoquinhydrone j Pt + Xyloquinone 0-002M I 25.4'. Temp. 7 - F Minutes ............... 20 60 120 Volt I .................. 0.1069 0.1070 0.1069 , 11 ............... 0-1070 0.1069 0.1069 ~ 2 5 - = 0.5949 208 MITCHELL HYDROLYSIS OF THE d-OLUCOSIDES ETC.DichZoroxyZoquinhydrone.-1 G. of monochloroxylohydroquinoiie in 20 C.C. of water and 20 C.C. of alcohol was oxidised with 29 C.C. of 0-2N-ferric ammonium alum. The product was washed with water. Yield 0.7 g. (0.0993 reduced 5-85 C.C. of 0.0983 5-iodine. Monochlorohydroquinone found = 49.6 calc. = 50.0%). TABLE XVI. - Pt I Dichloroxyloquinhydrone ; 0-1N-HC1 ; Benzoquinhydrone I Pt + 25.14'. Temp. / - Minutes ............... 30 65 125 150 Volt I ............... 0.1069 0.1070 0.1071 0.1071 .. I1 ............... 0.1072 0.1073 0.1074 0.1074 The values of x given in Tables IV V XI XII XIV and XVI are the results of direct determinations whilst those given in the other tables (excluding I) are indirect values. ~ 2 5 ~ = 0.5918.THE UNIVERSITY COPENHAGEN. [Received Au!qust 23rd 1924. THE REDUCTION POTENTIALS OF QUINHYDRONES. 199 XXXII. -Method of Measuring the Reduction Potentia'ls of Quinh ydrones. By EINAR BIILMANN A. LANGSETH JENSEN and KAI 0. PEDERSEN. IT has been pointed out by one of us (Trans. Faraduy Xoc. 1923, 19 676) that the reduction potential of a quinhydrone can be determined by measuring the potential of an electrode containing, for instance the hydroquinone of one quinhydrone in a solution of the quinone of another quinhydrone with a known reduction potential, that is without preparing the quinhydrone itself or both its con 200 BIILMANN JENSEN AND PEDERSEN METHOD OF (a) Pt I (a ; electrolyte ; (AYAH,) stituents. In this paper the theory of the method is described and some quantitative results are detailed.Let A AH, and (A,AH,) be a certain quinone hydroquinone, and quinhydrone respectively and let By BH, and (B,BH,) be another similar series. Then if a solution of the hydroquinone, AH, be mixed with a solution of the quinone By AH will be partly oxidised to the quinone A a t the expense of By which will be partly reduced to its corresponding hydroquinone BH,. Starting with equimolecular quantities of AH and By the reaction may be written aAH + aB + (a - x)AH + xA + (a - x)B + xBH . (1) and the equilibrium set up must be such that the reduction potential T (as measured against a hydrogen electrode) of the mixture (a - x)AH + xA is equal to the reduction potential of the mixture (a - x)B + xBH,. We have now four electrolytic chains to consider Pt Pt I c " l ~ y ~ ~ B ; electrolyte ; (B,BH,) ( b ) the similar chain Pt RT a - x - X += __ nF .loge- X - - K log10 rx (3) so that 4 = - +'; ( c ) the quinhydrone electrode with the reduction potential xof ; and ( d ) the quinhydrone electrode with the reduction potential xo.Pt 1 (A,AH,) ; H I Pt Pt I (BYBH,) ; H I Pt x = x o f - + = x o + + z.e. nof = 2ic -Tco=2++xo . . . (4) Now for equilibrium we must have where x is the voltage both of the chain (a - x) . mAH PtI x.mA i H 2 I P t and of the chai MEASURING THE REDUCTION POTENTIALS OF QUINHYDRONES. 201 That is to say the reduction potential no' of the quinhydrone (i) the potential X of a mixture of the hydroquinone AH with an equimolecular quantity of the quinone B (or conversely) to a hydrogen electrode.or (ii) the potential #, of this mixture to the quinhydrone electrode (A,AH,) can be determined by measuring (B,BH,). 0.75 0.70 0.65 0.60 2 \ N <A I-In both cases we require to know the reduction potential no, of the quinhydrone (B,BH,) electrode; and obviously the electro lyte the temperature and the hydrogen pressure (1 atm.) must be the same in all the electrodes. Combining equations (3) and (4) we get no' - = 2+ = 2K log,(){x/(a - x)) = (at 25') 0.0591 log,,{x/(a - x)), from which equation x may be calculated when no and xo' have been determined. Taking the reduction potentials at 25" for benzoquinhydrone, toluquinhydrone and p-xyloquinhydrone as 0.6990 0-6454 and H 202 BIILMANN JENSEN AND PEDERSEN METHOD OF 0.5886 volt respectively the following values for the percentage of quinhydrone unchanged in equimolecular mixtures with quinones are obtained : yo Hydroquinone 12.4 1.4 Mixture.unchanged. Benzoquinone + Toluhydroquinone . . . . . . . . . Benzoquinone + p-Xylohydroquinone . . . . . Toluquinone + p-Xylohydroquinone . . . . . . 9.1 Two sources of error must be briefly mentioned. First the position of the equilibrium markedly affects the accuracy attain-able. Fig. 1 shows the relation between the composition of the solution and the potential referred to a hydrogen electrode at 25". Thus p denotes the potential (0.72 volt) of a mixture of 18-5y0 of benzohydroquinone and 8l.5yO of benzoquinone. Similarly A B, and C denote the potentials of the three quinhydrones.Now the potential of the equilibrium mixture of toluhydroquinone and benzoquinone is given by point a (the intersection of the corre-sponding curves) and it is obvious from the figure that the farther this point is removed from the centre line ABC the more rapidly will the potential change with composition and the less accurate will be the results. The second source of error is due to the inequality of the dis-sociation constants * of the various quinhydrones. At 25" the dissociation constant of benzoquinhydrone is 0.224 whilst for toluquinhydrone it is 0.095 (Biilmann Ann. Chim. 1921 [ix] 15, 151). But by comparing the values obtained by the " mixture " method with those obtained directly by La Mer ( J . Arner Chem.SOC. 1922 44 1954) and one of us (Biilmann Zoc. cit.) and also in this research it is seen that satisfactory agreement is obtained, * Let the initial concentrations of A and BH be a and the stoicheio. metric amounts of the quinones and hydroquinones a t equilibrium (as assumed in equation 1) be AH, a - x; A x ; BH, x; and By a - x. If the concentrations of undissociated quinhydrones AH,,A and BH,,B are a and p respectively the concentrations of the dissociated components will be AH, a - 1 - a; A x - a; BH, x - p ; and B a - x - /3. In the equilibrium set up the potentials of the mixtures of A and AH and of B and BH against the corresponding two quinhydrones are (equation 2) $A =K1ogl,a - - a a - x - / I If as supposed T,' - T = 2$ we have c p ~ = $B and consequently, (x - .)/(a - x - a) = (x - P)/(a - x - /3) or 2x(a - /3) = a(.- p). Consequently the supposed relation between the potential of the mixture and the reduction potentials of the single quinhydrones is strictly exact if a = /3 Le. the two quinhydrones have the same dissociation constants [as kA = (x - a)(o x - a)/u; kB = (z /?)(a - z - /3)//3] or if x = a / 2 , Le. their reduction potentials are identical. - ' respectively. x - a and $B = K log, MEASURING THE REDUCTION POTENTIALS OF QUINHYDRONES. 203 especially when the sparing solubility of the materials dealt with is considered. I n some cases the equilibrium potential was reached almost instantaneously; in others it was necessary to wait for some hours before measurement. Table I records the experimental results.TABLE I. Reduction Potentids of Quinhydrones. ?ro measured in raisture. At 18". At 25". 0.6496 0.6444 - 0.5893 0.7178 0.7124 0.7174 0.7120 0.7280 0.7230 0.7280 0.7228 - 0.ti.542 - 0.65ti4 - 0.5949 * Biilmann Zoc. cit. t La Mer loc. Other deter-minations of ro at 25'. 0.6454 * 0.5886 0.7125 t 0.7151 t --0.6566 0.659 1 0.59 18 c i t . E Y P E R I M E N T A L. Toluhydroguinon e.-The t oluh ydroquin one was recryst allised from toluene immediately before the solution was made up. Equal volumes of 0.0 141-solutions of toluhydroquinone and benzoquinone in 0-liV-hydrochloric acid were mixed and the potentials measured against a benzoquinhydrone electrode blank platinum electrodes being used. TABLE 11.- p t I Toluhydroquinone 0*005A" ; ::& ; Benzoquinhydrone I Pt + Benzoquinone 0-00dJ1 254". 18". Temp. 7- - Minutes ............ 30 60 150 180 Volt I * ............ 0.0273 0.0273 0.0274 0.0274 .. I1 * ......... 0.0274 0.0274 0.0275 0.0275 ~ z j " = 0.6444. r 1 3 = = 0.6496. * Duplicate electrodes. p-SyZohydro~~inoize.-The potentials were measured as above, but the electrolyte was 0.lK-sulphuric acid saturated with carbon dioxide and all the operations were carried out in an atmosphere of this gas. H* 204 BIILMANN JENSEN AND PEDERSEN METHOD OF 25.4". Temp. r- .J \__ - .-Minutes 25 60 106 135 165 195 1200 1290 1460 Volt I 0-0689 0.0775 0.0802 0.0809 0.0811 0-0813 0.0820 0.0821 0.0821 0.0702 0.0773 0.0792 0-0803 0.0807 0.0810 0.0822 0.0822 0.0823 , I1 1~25" = 0.5893.Solution prepared from equimolecular quantities of p-xylohydro-quinone and p-xyloquinone in 0-1N-sulphuric acid with carbon dioxide treatment as before. TABLE IV. 25.6". 18". Temp. A ,-'-, Minutes ......... 5 45 95 145 185 3 85 Volt I ......... 0.1101 0.1104 0-1104 0.1104 0-1103 0-1104 ,) I1 ......... 0.1102 0.1105 0.1105 0.1105 0.1105 0.1106 7250 = 0.5886. p1g = 0.5940. f Without the carbon dioxide treatment constant potentials could not be obtained. The potentials measured against the benzoquinhydrone electrode of a similar electrode prepared wit'h-out the carbon dioxide treatment are recorded in Table V and it will be seen that the potentials slowly rise until after 20 hours, they are practically identical with those in Table IV.This may be due to catalytic oxidation of the hydroquinone on the surface of the platinum the potential reaching the value in Table IV only when the solution in the electrode vessel is thoroughly mixed by diffusion. TABLE V. 25.4'. Temp. / A \ Minutes ......... 15 60 120 150 1120 1270 Volt I ......... 0.1072 0.1090 0.1099 0.1100 0.1101 0.1101 .. I1 ......... 0.1070 0.1093 0-1098 0.1099 0.1103 0.1103 MonochZorohydroquinone.-Benzoquinone (10 g.) was heated with 100 C.C. of concentrated hydrochloric acid for 2 hour on the steam-bath (Wohler AnnaZen 1844 51 155) the solution cooled, diluted with water and extracted with ether. The residue after evaporation of the ether had m. p. 103" when crystallised twice from chloroform and 105-105.5" (constant) when crystallised TWO = 0.5888 MEASURING THE REDUCTION POTENTIALS OF QUINHYDRONES.205 subsequently from carbon tetrachloride. Levy and Schultz quote 106" (ibid. 1881 210 138) and Schultz quotes 103-104" (Ber., 1882 15 654). TABLE VI. - Pt Benzoquinhyclrone HC1 . Monochlorohydroquinone 0.005M 1 Pt + 0.1N ' Benzoquinone 0.005M 23.4". 18". Temp. e- - F ,----. 18O.* Minutes ......... 15 30 60 120 180 Volt 1 ......... 0.0068 O*OOGS 0.0068 0.0067 0.0067 0.0006 , I1 ......... 0.0067 0.0067 0.0067 O*OOGG 0.0066 0.0066 * After dilution with 3 vols. of O.lX-HC1. A2j" = 0.7124. q g = 0.7178. Jlonobromohydroquinone was prepared after Sarauw's method (dnm,Zen 1881 209 105). Bromine (16 g.) in 100 C.C. of ether was added to 11 g. of hydroquinone in 259 C.C.of ether and the solution allowed to evaporate a t laboratory temperature. The residue was extracted with 260 C.C. of toluene at 90-95" filtered off and cooled. Recrystallised from 100 C.C. of toluene 5 g. gave 3.8 g. m. p. 110.5" unchanged by further recrystallisation. Yield 10 g. m. p. 109.8". Sarauw quotes m. p. 110-111". TABLE VII. - pt 1 Benzoquinhydrone ; HC1 . R'onobromoh~dro~uinone~ 0*05M pt + 0-1N ' Benzoquinone 0.05X 23.4". 1 SO. 150.* Temp. .-*-- 7.7 ,-I---. bIinutes ...... 15 30 5 5 so 125 15 55 Volt I ...... 0.0008 0.0005 0.0063 0.0065 0.0065 0.0063 O.OOci3, , I1 ...... 0.0068 0.0083 0.0065 0.0065 0.0065 0.0064 0.00G4, * After dilution with 3 vols. of O.1N-HCI. ~ 2 ~ ' = 0.7120. p l y " = 0.7174. 2 5-DichZorohydroqui~~o~~e.-Prepared by Ling's method (J., 1S92 61 65S) and twice crystallised from water the substance had a constant m.p. 169-170". Ling quotes 172" and Levy and Schultz (Zoc. cit.) 166". TABLE VIII. - Benzoquinhydrone HC1 . Dichlorohydroquinone O.OO25M j Pt + 0.1N ' Benzoquinone 0.0025111 25.4". 18". Temp. /- - 7'\7 1 )so.* Minutes . . . . . . . . . . . . . . . 15 30 90 150 T'olt I ............... 0.0121 0.0120 0~011s 0.0118 0.0117 . I1 ............... 0.0120 0.0120 0.0118 0.0118 0.0117 ~ 2 5 ~ == 0.7230. = 0.7280. * After dilution with 3 vols. ol 0-1N-HCI. 2 5-Dibromohydroquinone.-Prepared by the method of Beiiedict (No12cwtsh. 1880 1 345) and of Sarauw (Zoc. cit.) and twice crystal 206 BIILMANN JENSEN AND PEDERSEN METHOD OF lised from water the compound had the m.p. 186" recorded by those investigators. TABLE IX. Bemohydroquinone ; HC1 . Dibromohydroquinone 0.001M 0-1N ' Benzoquinone 0.001M 25.4'. 18". Temp. & - Minutes ............... 30 60 90 120 Volt I ............... 0.0119 0.0119 0.0119 0.0119 , I1 ............... 0.0119 0.0119 0.0117 0.0117 T ~ O = 0.7228. ~ 1 8 0 = 0.7280. Monochloroto1uhydroquinone.-Prepared by Schniter's method (Ber. 1887 20 2282) and crystallised from toluene and then twice from chloroform the product had m. p. 172-174" (uncorr.). Schniter quotes m. p. 175" [0.2048 reduced 26.0 C.C. of 0-1002N-iodine corresponding to 10043~o of C,H&eCl(OH),. C1 found = 22.26; calc. = 22.26%]. The hydrochloric acid used in the measurements was aerated with carbon dioxide. TABLE X.25". r \ Temp. 1-Minutes ......... 10 40 100 150 175 1380 Volt I . . . . . . . . 0.0217 0.0220 0.0222 0.0222 0-0223 0.0225 , I1 ......... 0.0214 0.0219 0.0223 0.0226 0.0227 0.0229 Mean = 0.0224 ~ 2 5 . = 0.6542. Dichloroto1uquinhydrone.-Prepared by oxidising the correspond-ing hydroquinone in 50% alcohol with the calculated quantity of ferric ammonium alum. TABLE XI. -Pt I Dichlorotoluquinhydrone ; 0-1N-HCI ; Benzoquinhydrone 1 Pt + Temp. // \ 25". Minutes ...... 30 60 100 128 175 210 1110 1225 Volt I ...... 0.0394 0-0400 0.0406 0-0410 0.0415 0-0418 0.0425 0.0424 , I1 ...... 0-0382 0.0397 0*0400 0.0404 0-0407 0.0410 0.0424 0-0424 , I11 ...... 0.0382 0.0399 0*0400 0.0404 0.0408 0.0410 0.0424 0.0423 ~ 2 6 0 = 0.6566. TABLE XII. .-Pt I Dichlorotoluquinhydrone 0.00052cI ; 0-IN-HCI ; Benzoquinhydrone I Pt + 18".Temp. -- -'.- - -___ -\ Minutes 20 Volt I ..................... 0.0419 0.0419 0.04 19 , I1 .................. 0.0419 0.0419 0.04 19 , I11 ........... . ...... 0.0419 0.04 19 0.04 19 . . . . . . . . . . . . . . . . . . 30 45 ~ 1 8 0 = 0.6625 MEASURING THE REDUCTION POTENTIALS OF QUINHYDRONES. 207 Il/lonobromotoluhydroquinone.-To 5 g. of toluhydroquinone in 100 C.C. of ether and 45 C.C. of chloroform were added 6.45 g. of bromine in 82 C.C. of chloroform. The product (64 g.) recrystal-lised twice from toluene melted at 176-178". Clark (Amer. Chem. J . 1892 14 569) quotes 176-179". TABLE XIII. - '~.ionobromotoluh~dro~uinonc~ o.oo25nf ; ::& ; Bcnzoquinhr-drontl l>t + l'tlBenzoquinone 0.b023111 23".Temp. /-- - \---Minutes ............... 15 70 185 235 5lV Volt I ............... 0.0209 0.0210 0.0212 0.0213 0.0214 .. I1 ............... 0.0205 0.020G 0.0208 0*0208 0.0213 Dibromoto1uquinhydrone.-Prepared by oxidising 1 g. of mono-bromotoluhydroquinone in 5 C.C. of alcohol with 12.25 c.c=. of O.2M-ferric ammonium alum the product was washed with water and dried between filter-paper (0.2003 titrated in presence of sodium bicarbonate with 0-0849N-iodine required 11-75 C.C. Mono-bromotoluhydroquinone = 50-3yu ; calc. 50.0%). 1~250 = 0.6564. TABLE XIV -Pt IDibromotoluquinhydrone 0.00125M ; HC10.1N ; Benzoquinhydroml Pt + Temp. / -. Volt I ............... 0-0397 0.0399 0.0399 0.0399 25.2". Minutes ............... 30 90 120 1.55 , I1 ...............0.0397 0-0399 0.0399 0.0399 "'73" = 0,6591. ,MonochloroxyZohydroquinone.-Prepared by the method of v. Kad (Annulen 1869 151 166) and Carstanjen ( J . p. Chem. 1881, 23 430). 20 G. of p-xyloquinone were added to 200 C.C. of cold concentrated hydrochloric acid a further 300 C.C. of acid were added and the mixture was heated for 2-3 hours on the steam-bath. The crystals obtained on cooling were recrystallised from toluene carbon tetrachloride and twice from chloroform. Yield 7-75 g. m. p. 132-153" (Cl found 20.81 calc. 20.56%). TABLE XV. - pt M~nochlorox~loh~dro~uinone~ o.oo2Af ; zyb ; Benzoquinhydrone j Pt + Xyloquinone 0-002M I 25.4'. Temp. 7 - F Minutes ............... 20 60 120 Volt I .................. 0.1069 0.1070 0.1069 , 11 ............... 0-1070 0.1069 0.1069 ~ 2 5 - = 0.5949 208 MITCHELL HYDROLYSIS OF THE d-OLUCOSIDES ETC. DichZoroxyZoquinhydrone.-1 G. of monochloroxylohydroquinoiie in 20 C.C. of water and 20 C.C. of alcohol was oxidised with 29 C.C. of 0-2N-ferric ammonium alum. The product was washed with water. Yield 0.7 g. (0.0993 reduced 5-85 C.C. of 0.0983 5-iodine. Monochlorohydroquinone found = 49.6 calc. = 50.0%). TABLE XVI. - Pt I Dichloroxyloquinhydrone ; 0-1N-HC1 ; Benzoquinhydrone I Pt + 25.14'. Temp. / - Minutes ............... 30 65 125 150 Volt I ............... 0.1069 0.1070 0.1071 0.1071 .. I1 ............... 0.1072 0.1073 0.1074 0.1074 The values of x given in Tables IV V XI XII XIV and XVI are the results of direct determinations whilst those given in the other tables (excluding I) are indirect values. ~ 2 5 ~ = 0.5918. THE UNIVERSITY COPENHAGEN. [Received Au!qust 23rd 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700199

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

208 MITCHELL HYDROLYSIS OF THE ~-OLUCOSIDES ETC. XXXIII. -Hydrolysis of the d-Glucosides of d- and l-Borneo1 with Emulsin. By STOTHERD MITCHELL. DAKIN ( J . PhysioE. 1904 30 253) found that when an optically inactive mixture of t'he two methyl mandelates was acted upon by the enzyme lipase the dextro-component was hydrolysed more rapidly than the kevo. Substitution of other alkyl groups for methyl produced differences in the relative rates of hydrolysis, and in order to investigate the effect of optically active groups he prepared I-menthyl mandelate and d-bornyl mandelate. Lipase, however was without action on these compounds. Later (ibid., 1905 32 199) he succeeded in hydrolysing esters in which an asymmetric carbon atom was present in the alkyl group but not in the acid part of the molecule.The hydrolysing action of emulsin on the d-glucosides prepared from the two forms of borneol has now been examined. The d-borneol was obtained from commercial " borneol," which is a mixture of d-borneol and I-isoborneol resulting from the reduc-tion of camphor (Pickard and Littlebury J. 1907 91 1977). The purified d-borneol and the I-borneol used had [m]2;igreen = + 42-14' and - 42-20' respectively calculated from 15.4% solutions in dcohol. The p-glucosides of d- and I-borneol were prepared by treating p-tetra-acetylbromoglucose in ether with an excess of borneol i SONE CO-ORDINATED COMPOUNDS OF THE ALKALI METALS. 209 presence of silver carbonate the acetyl groups being subsequently removed by means of barium hydroxide (Fischer and Raske Ber., 1909 42 1473 ; Fischer Ber.1916 49 584 ; Hamalainen Biochern. Z. 1913 50 217). Emulsin (2.5 g.) was mixed with 180 C.C. of water and kept in a thermostat a t 37" for a day. The solution was filtered before use and gave E:; green - 0.64" (I = 1 dcm.). A small quantity (0.3 g.) of each glucoside (which contains 1H,O) was placed in a 50 C.C. flask in a thermostat a t 37". The hydrolysis of the d-bornyl-d-glucoside was started by filling the flask to the mark wit,h the emulsin solution and an hour later the hydrolysis of the I-bornyl-d-glucoside was commenced. Two C.C. were removed a t intervals and the amount of glucose present was determined by IiIacLeaa's method for estimating the sugar in blood (Biochern. J., 1919,13 135). The reaction constants are calculated from thc usual formula for unimolecular reactions k = {2.3O/(t - t,)l log (cz/c,).Time in mins. 2 70 330 515 613 860 ( = t Y ) d- BoriLyl-d-gliLcoside. Glucose. Glucositle. Time IIg. in BIg. in in 2 C.C. 2 C.C. k x lo5. mins. 0.70 10.13 10 1 so 0.77 10.01 9 303 0.82 9.92 11 36 1 0.89 9-80 1 0 43.5 1-03 9.55 673 Average 10 ( = t g ) I- Bomyl-d -p! zlcos ide. Glucose. Glucoside. 31s. in Mg. in 2 C.C. 2 C.C. k x 10". 0.87 9.83 34 1-12 9.39 33 1.2% 9.22 33 1-33 9.03 35 1.74 5-3 1 ,4veragc 3-1 Hence emulsin hydrolyses I- bornyl-d-glucoside 3-4 time as This is a striking example of the rapidly as d-bornyl-d-glucoside. selective nature of enzyme action. PHYSICAL CHEMISTRY DEPARTMENT, UNIVERSITY OF GLASC:OW.[Received Xovenlber 24th 1924. 208 MITCHELL HYDROLYSIS OF THE ~-OLUCOSIDES ETC. XXXIII. -Hydrolysis of the d-Glucosides of d- and l-Borneo1 with Emulsin. By STOTHERD MITCHELL. DAKIN ( J . PhysioE. 1904 30 253) found that when an optically inactive mixture of t'he two methyl mandelates was acted upon by the enzyme lipase the dextro-component was hydrolysed more rapidly than the kevo. Substitution of other alkyl groups for methyl produced differences in the relative rates of hydrolysis, and in order to investigate the effect of optically active groups he prepared I-menthyl mandelate and d-bornyl mandelate. Lipase, however was without action on these compounds. Later (ibid., 1905 32 199) he succeeded in hydrolysing esters in which an asymmetric carbon atom was present in the alkyl group but not in the acid part of the molecule.The hydrolysing action of emulsin on the d-glucosides prepared from the two forms of borneol has now been examined. The d-borneol was obtained from commercial " borneol," which is a mixture of d-borneol and I-isoborneol resulting from the reduc-tion of camphor (Pickard and Littlebury J. 1907 91 1977). The purified d-borneol and the I-borneol used had [m]2;igreen = + 42-14' and - 42-20' respectively calculated from 15.4% solutions in dcohol. The p-glucosides of d- and I-borneol were prepared by treating p-tetra-acetylbromoglucose in ether with an excess of borneol i SONE CO-ORDINATED COMPOUNDS OF THE ALKALI METALS. 209 presence of silver carbonate the acetyl groups being subsequently removed by means of barium hydroxide (Fischer and Raske Ber., 1909 42 1473 ; Fischer Ber.1916 49 584 ; Hamalainen Biochern. Z. 1913 50 217). Emulsin (2.5 g.) was mixed with 180 C.C. of water and kept in a thermostat a t 37" for a day. The solution was filtered before use and gave E:; green - 0.64" (I = 1 dcm.). A small quantity (0.3 g.) of each glucoside (which contains 1H,O) was placed in a 50 C.C. flask in a thermostat a t 37". The hydrolysis of the d-bornyl-d-glucoside was started by filling the flask to the mark wit,h the emulsin solution and an hour later the hydrolysis of the I-bornyl-d-glucoside was commenced. Two C.C. were removed a t intervals and the amount of glucose present was determined by IiIacLeaa's method for estimating the sugar in blood (Biochern. J., 1919,13 135). The reaction constants are calculated from thc usual formula for unimolecular reactions k = {2.3O/(t - t,)l log (cz/c,). Time in mins. 2 70 330 515 613 860 ( = t Y ) d- BoriLyl-d-gliLcoside. Glucose. Glucositle. Time IIg. in BIg. in in 2 C.C. 2 C.C. k x lo5. mins. 0.70 10.13 10 1 so 0.77 10.01 9 303 0.82 9.92 11 36 1 0.89 9-80 1 0 43.5 1-03 9.55 673 Average 10 ( = t g ) I- Bomyl-d -p! zlcos ide. Glucose. Glucoside. 31s. in Mg. in 2 C.C. 2 C.C. k x 10". 0.87 9.83 34 1-12 9.39 33 1.2% 9.22 33 1-33 9.03 35 1.74 5-3 1 ,4veragc 3-1 Hence emulsin hydrolyses I- bornyl-d-glucoside 3-4 time as This is a striking example of the rapidly as d-bornyl-d-glucoside. selective nature of enzyme action. PHYSICAL CHEMISTRY DEPARTMENT, UNIVERSITY OF GLASC:OW. [Received Xovenlber 24th 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700208

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

SONE CO-ORDINATED COMPOUNDS OF THE ALKALI METALS. 209 XXXIV. -Some Co-ordinated Compounds of the Alkali Metals. By NEVIL VIKCENT SIDGWICK and SYDNEY GLENN PRESTON PLAXT. THE action of alkalis on $-indoxylspirocyclopentane (I) (Perkin and Plant J. 1923 123 676) has been examined and compounds of the type &lB,HB [HB = (I) ; M = Li Na or K] obtained which are soluble in toluene and behave as 4-covalent metallic compounds. c 210 SOME CO-ORDINATED COMPOUNDS OF THE ALKALI METALS. The Sodium Derivative.-Four grams of (I) were heated wit'h sodium hydroxide (10 g.) in water (40 g.) in an air-tight steel tube a t 210" for $ hour. After cooling the solid sodium derivative was washed out from the tube with aqueous sodium hydroxide (20%) and removed by filtration through asbestos.After drying on the steam-bath it crystallised slowly from toluene in clusters of small, colourless prisms melting a t 204" to a cloudy liquid (Found : Na = 6.1. It is decomposed a t once by water to re-form the indoxyl compound (I). When distilled in a vacuum it gives a colourless distillate identical with (I) ; an infusible residue remains which yields (I) with dilute hydrochloric acid. Prolonged boiling with toluene causes a similar decomposition with the separation of a colourless precipitate, The Potassium Derivative.-Four grams of (I) were heated with 40 C.C. of aqueous potassium hydroxide (30%) in the steel tube for 4 hour a t 200-210". On pouring out after cooling the potassium compound appeared as an oil which soon solidified to a colourless mass.This separated from toluene in colourless plates melting to a cloudy liquid a t 80-90" (Found K = 9.6. C,,H,,ONK,C,,H,,ON requires K = 9.5%). It gives (I) a t once with water and also on distillation when it leaves an infusible residue; when it is boiled for a few minutes wit'h toluene a colourless precipitate separates. The Lithium Deriz.atiwe.-Four grams of (I) were heated with 40 C.C. of water saturated with lithium hydroxide a t 15" for 6 hour in the steel tube a t 200". The product was washed out with lithium hydroxide solution and removed by filtration through asbestos. After drying in a desiccator it melted a t 170" to a cloudy liquid [(I) melts at 113'1 (Found Li = 1.97. C,,H,,ONLi,C,,H,,ON requires Li = 1.84y0). It was decomposed by water to give the indoxyl compound.Attempts to recrystallise it from dry benzene, toluene ligroin and chloroform caused complete decomposition into this compound and a very small residue containing lithium. Discussion of Results. The action of alkali hydroxides even in very large excess, on this indoxyl compound gives a substance MB,HB in which one metallic atom replaces one hydrogen atom in 2 mols. This loses 1 mol. of HB on heating either alone or in toluene solution forming no doubt the simple salt MB which we should expect the indoxyl derivative to produce. There can be little doubt that the first product MB,HB contains a co-valent metallic atom. The indoxyl ring admits of co-ordination between a metal replacing the imide hydrogen and the carbonyl oxygen, C,,H,,ONNa,C,,H,,ON requires Na = 5.8%) HAMER REDUCTION O F THE CARBOCXANINES.S l l with the formation of the typical chelate ring of 6 atoms with two conjugate double links (see formula II) as in acetoacetic ester acetylacetone nitroso- ,&naphthol etc. (see Sidgwick Trans. Faraday Soc. 1923 19 474). The strong tendency of the alkali metals to ionise will prevent the formation of this ring in the simple derivatives MB which therefore are salts ; but the greater stability secured by the completion of four non-polar links causes these compounds to add a second molecule of the indoxyl derivative (without replacement of hydrogen) giving the structure 11. The remarkable solubility in toluene is thus explained since the compound is not a salt. The sodium has its octet completed by means of three pairs of shared electrons borrowed from the two oxygens and the now quadrivalent nitrogen.The second ring, being attached only by co-ordinate links is easily removed and hence the compound dissociates on heating. The potassium compound is precisely similar in behaviour, although it has a markedly lower melting point (80-90" instead of 204"). Lithium seems to form an analogous compound m. p. 170" but owing to its great instability this could not be purified. These appear to be the I'irst recognised co-ordination compounds of sodium and potassium. THE DYSON PERRINS LABORATORY, OXFORD. [Received Socember 28th 1924. SONE CO-ORDINATED COMPOUNDS OF THE ALKALI METALS. 209 XXXIV. -Some Co-ordinated Compounds of the Alkali Metals.By NEVIL VIKCENT SIDGWICK and SYDNEY GLENN PRESTON PLAXT. THE action of alkalis on $-indoxylspirocyclopentane (I) (Perkin and Plant J. 1923 123 676) has been examined and compounds of the type &lB,HB [HB = (I) ; M = Li Na or K] obtained which are soluble in toluene and behave as 4-covalent metallic compounds. c 210 SOME CO-ORDINATED COMPOUNDS OF THE ALKALI METALS. The Sodium Derivative.-Four grams of (I) were heated wit'h sodium hydroxide (10 g.) in water (40 g.) in an air-tight steel tube a t 210" for $ hour. After cooling the solid sodium derivative was washed out from the tube with aqueous sodium hydroxide (20%) and removed by filtration through asbestos. After drying on the steam-bath it crystallised slowly from toluene in clusters of small, colourless prisms melting a t 204" to a cloudy liquid (Found : Na = 6.1.It is decomposed a t once by water to re-form the indoxyl compound (I). When distilled in a vacuum it gives a colourless distillate identical with (I) ; an infusible residue remains which yields (I) with dilute hydrochloric acid. Prolonged boiling with toluene causes a similar decomposition with the separation of a colourless precipitate, The Potassium Derivative.-Four grams of (I) were heated with 40 C.C. of aqueous potassium hydroxide (30%) in the steel tube for 4 hour a t 200-210". On pouring out after cooling the potassium compound appeared as an oil which soon solidified to a colourless mass. This separated from toluene in colourless plates melting to a cloudy liquid a t 80-90" (Found K = 9.6.C,,H,,ONK,C,,H,,ON requires K = 9.5%). It gives (I) a t once with water and also on distillation when it leaves an infusible residue; when it is boiled for a few minutes wit'h toluene a colourless precipitate separates. The Lithium Deriz.atiwe.-Four grams of (I) were heated with 40 C.C. of water saturated with lithium hydroxide a t 15" for 6 hour in the steel tube a t 200". The product was washed out with lithium hydroxide solution and removed by filtration through asbestos. After drying in a desiccator it melted a t 170" to a cloudy liquid [(I) melts at 113'1 (Found Li = 1.97. C,,H,,ONLi,C,,H,,ON requires Li = 1.84y0). It was decomposed by water to give the indoxyl compound. Attempts to recrystallise it from dry benzene, toluene ligroin and chloroform caused complete decomposition into this compound and a very small residue containing lithium.Discussion of Results. The action of alkali hydroxides even in very large excess, on this indoxyl compound gives a substance MB,HB in which one metallic atom replaces one hydrogen atom in 2 mols. This loses 1 mol. of HB on heating either alone or in toluene solution forming no doubt the simple salt MB which we should expect the indoxyl derivative to produce. There can be little doubt that the first product MB,HB contains a co-valent metallic atom. The indoxyl ring admits of co-ordination between a metal replacing the imide hydrogen and the carbonyl oxygen, C,,H,,ONNa,C,,H,,ON requires Na = 5.8%) HAMER REDUCTION O F THE CARBOCXANINES. S l l with the formation of the typical chelate ring of 6 atoms with two conjugate double links (see formula II) as in acetoacetic ester acetylacetone nitroso- ,&naphthol etc.(see Sidgwick Trans. Faraday Soc. 1923 19 474). The strong tendency of the alkali metals to ionise will prevent the formation of this ring in the simple derivatives MB which therefore are salts ; but the greater stability secured by the completion of four non-polar links causes these compounds to add a second molecule of the indoxyl derivative (without replacement of hydrogen) giving the structure 11. The remarkable solubility in toluene is thus explained since the compound is not a salt. The sodium has its octet completed by means of three pairs of shared electrons borrowed from the two oxygens and the now quadrivalent nitrogen. The second ring, being attached only by co-ordinate links is easily removed and hence the compound dissociates on heating. The potassium compound is precisely similar in behaviour, although it has a markedly lower melting point (80-90" instead of 204"). Lithium seems to form an analogous compound m. p. 170" but owing to its great instability this could not be purified. These appear to be the I'irst recognised co-ordination compounds of sodium and potassium. THE DYSON PERRINS LABORATORY, OXFORD. [Received Socember 28th 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700209

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

HAMER REDUCTION O F THE CARBOCXANINES. 211 XXXV. -Reduction of the Carbocyanines. By FRANCES &lARY HAJIER. THE constitution (I) of carbocyanine was deduced from general considerations supported by analytical evidence and established by the study of the oxidative breakdown of pinacyanole (Ifills and Hamer J. 1920 117 1550). The prediction of similar classes of dyes with the nuclei linked in the 4 4’- and 2 4’-positions, respectively has now been fulfilled (Mills and Braunholtz J., (1.1 (II.) 1923 123 2804; Mills and Odams J. 1924 125 1913) thus confirming the formula. Two syntheses have been adduced in its support. Konig’s ( B e y . 1922 55 3293) consists in condensation of quinaldine alkyl 212 HAMER REDUCTION OF THE CARBOCYANINES. halide with orthoformic ester in presence of acetic anhydride.It is not obvious why this is considered to throw more light on the constitution of ca,rbocyanine than does the earlier preparation by the action of formaldehyde on an alcoholic solution of quinaldine alkylhalide in presence of alkali (Mills and Hamer Zoc. cit.). The synthesis by means of orthoformic ester does however differ from the latter as from the preparation in which the formaldehyde is replaced by a trihalogenmethane (D.R.-P. 200,207) in that a 50% yield of analytically pure product is claimed. But when Konig’s procedure was repeated it was found that even twice the quoted amount of acetic anhydride was barely sufficient for solution of the given quantity of quinaldine ethiodide and that the con-siderable yield of crude product consisted chiefly of impurities.The method is said to be equally applicable to the more soluble methiodide but when this was used in order that the directions might be followed exactly the yield of pure carbocyanine was not more than 10%. In the second synthesis (Hamer J. 1923 123, 246) methylenediquinaldine dialkylhalide was prepared from quinaldine alkylhalide and formaldehyde according to the equation : The action of alkali in presence of quinoline alkylhalide elimin-ated halogen acid with apparently simultaneous removal of two hydrogen atoms since carbocyanine (I) was directly formed. This synthesis proves the existence of a three-carbon chain joining the quinoline nuclei of the carbocyanine molecule and is unequivocal except for the unexplained fact that the presence of quinoline alkylhalide is necessary.The converse transformation of carbocyanine into methylene-diquinaldine dialkylhalide has now been accomplished thus clearly demonstrating the relationship. The addition of hydriodic acid (b. p. 126”) to 1 1’-dirnethylcarbocyanine iodide gave yellow crystals too unstable to isolate for analysis but doubtless pos-sessing formula 11 which only requires addition of two hydrogen a toms to represent met h ylenediqu inaldine dime t hio dide . This reduction was brought about by heating with excess of hydriodic acid at a carefully regulated temperature and a 78% yield of methylenediquinaldine dimethiodide was the result. Simi-larly 1 1‘-diethylcarbocyanine iodide and 6 6’-dimethyl-1 1‘-diethylcarbocyanine iodide were reduced to methylenediquinaldine diethiodide and 6 6’-dimethylmethylenediquinaldine diethiodide, respectively.The temperature is an important factor in th HAMER REDUCTION O F THE CARBOCYANINES. 213 reduction since with a lowering of a few degrees unchanged carbo-cyanine remains whilst too high temperatures lead to decomposition of the dialkylhalide. p-Dimethylaminobenzylidenequinaldine ethiodide was similarly heated with hydriodic acid but analysis of the product proved that, besides reduction of the ethylenic linking the two methyl groups had been replaced by hydrogen atoms. That the compound was p-aminobenzylquinaldine ethiodide and not the hydriodide of p-dimethylaminobenzylidenequinaldine was established by the fact that it was neutral and unattacked by ammonia.F x P E R I M E N T A L. Preparation of 1 1'-Dimethylcarbocyanine Iodide by Use of Cirthoformic Ester (compare Konig loc. cit .).-Quinaldine methiodide (6 g.) was boiled with acetic anhydride (60 c.c. b. p. 135-140"), and during 5 minutes orthoformic ester (2.1 g. b. p. 142-146") was added. The mixture was concentrated to half volume and the solid removed when cold. The greater part of the impurity was extracted by boiling methyl alcohol (15 c.c.) and the undissolved crude carbocyanine was recrystallised from methyl alcohol (yield 67; instead of 50). The method recommended in a later paper (Ber. 1924 57 685) gave a 10% yield. Reduction of 1 1 '-Dimethylcarbocyaizine Iodide.-By heating the carbocyanine (1.5 g . ) with hydriodic acid (10 c.c.b. p. 126") in a sealed tube a t 182-185" for 6 hours black crystals of periodide were produced; addition of water gave a yellow precipitate. The total solid was suspended in boiling 1.5% hydrochloric acid and sulphur dioxide passed in until a clear solution was obtained when potassium iodide was added (1.5 g.). The product (yield 780/) mas recrystallised from dilute hydrochloric acid with charcoal treatment and addition of potassium iodide. The crystals were ground with pyridine (5 c.c.) to remove any acid impurity (see below) washed with acetone recrystallised from absolute alcohol, and dried in the steam-oven (Found C = 47.27; H = 4-19: I = 43.41. Calc. for C2,H2,N,T2 C = 47.42; H = 4.16; I = 43.617;) ; m. p. 20'7" (decornp.) alone or mixed with methylene-diquinaldine dimethiodide.The compound had the properties of this substance and its crystallisation could be started by inoculation with it. By reduction of the carbocyanine a t 203-209" the iodide obtained after two recrystallisations from absolute alcohol was strongly acid ; it appeared to be free from methylenediquinaldine dimethiodide since it was completely and easily soluble in cold pyridine in which the dimethiodide is practically insoluble 214 HAMER REDUCTION OF THE CARBOCYANINES. Reduction of 1 1'-Diethylcarbocyanine Halide.-The iodide or bromide (1 g.) was heated with hydriodic acid (7 c.c.) at 178-181" and on reduction of the resultant periodide the crystalline product (yield 76%) was almost pure (Found I = 41.27y0).It was treated with pyridine and recrystallised from absolute alcohol (yield 54%). This reduction product methylenediquinaldine diethiodide and their mixture melted simultaneously a t 205" (decomp.). For analysis it was dried in the steam-oven (Found : C = 48.80; H = 4.73; I = 41.62. Calc. for C25H28N212 C = 49.18; H = 4.63; I = 41-61y0). Reduction of 6 6'-Dimethyl-1 1 '-diethylcarbocyanine Iodide.-Hydriodic acid (5 c.c.) and the carbocyanine (0.5 g.) [fine needles of the almost colourless hydriodide formed] were heated a t 178-185" for 5 hours and the solid was treated with sulphur dioxide as in other cases (yield 83%). For analysis the iodide was dried over sulphuric acid and soda-lime (Found I = 38-97. Calc. for C,,H,,N21,,H,0 I = 38.68%). It melted at 219" alone or mixed with 6 6'-dimethylmethylenediquinaldine diethiodide.The m. p. was unaltered by recrystallisation. Reduction of p-Dimethylaminobenxylidenequinaldine Ethiodide.-This was prepared by the method of Konig and Treichel ( J . pr. Chenx. 1921 [ii] 102 63). By increasing the time of heating from 1 hour to 24 hours the yield of recrystallised product was raised from 23 to 76% (Found I = 29.33; calc. 29.51%); m. p. 259-263" (decomp.). p-Dimethylaminobenzylidenequinaldine ethiodide ( 1 -5 g.) and hydriodic acid (10 c.c.) were heated for 3 hours at 178-181" water was added and the solid in boiling dilute hydrochloric acid treated with sulphur dioxide. The clear solution gave no precipitate with potassium iodide (1.5 g.) but ammonia produced an orange ta,r which hardened and was powdered filtered and dried in a vacuum desiccator.From absolute alcohol it separated as clear red crystals (yield 59%). A thrice recrystallised specimen was dried in a vacuum desiccator and was shown by analysis to be p-aminobenzyl-quinaldine ethiodide (Found C = 56.64 ; H = 5.26 ; N = 7.08 ; I = 31.30. CI9H,,N,I requires C = 56.41 ; H = 5-24 ; N = 6-93 ; I = 31.41y0). It is moderately soluble in alcohol or water ; m. p. 200-201" with incipient softening a couple of degrees lower. UNIVERSITY CREMICAL LABORATORY CAMBRIDGE. DAVY FARADAY RESEARCH LABORATORY ROYAL INSTITUTION. [Received November 22nd 1924. HAMER REDUCTION O F THE CARBOCXANINES. 211 XXXV. -Reduction of the Carbocyanines. By FRANCES &lARY HAJIER. THE constitution (I) of carbocyanine was deduced from general considerations supported by analytical evidence and established by the study of the oxidative breakdown of pinacyanole (Ifills and Hamer J.1920 117 1550). The prediction of similar classes of dyes with the nuclei linked in the 4 4’- and 2 4’-positions, respectively has now been fulfilled (Mills and Braunholtz J., (1.1 (II.) 1923 123 2804; Mills and Odams J. 1924 125 1913) thus confirming the formula. Two syntheses have been adduced in its support. Konig’s ( B e y . 1922 55 3293) consists in condensation of quinaldine alkyl 212 HAMER REDUCTION OF THE CARBOCYANINES. halide with orthoformic ester in presence of acetic anhydride. It is not obvious why this is considered to throw more light on the constitution of ca,rbocyanine than does the earlier preparation by the action of formaldehyde on an alcoholic solution of quinaldine alkylhalide in presence of alkali (Mills and Hamer Zoc.cit.). The synthesis by means of orthoformic ester does however differ from the latter as from the preparation in which the formaldehyde is replaced by a trihalogenmethane (D.R.-P. 200,207) in that a 50% yield of analytically pure product is claimed. But when Konig’s procedure was repeated it was found that even twice the quoted amount of acetic anhydride was barely sufficient for solution of the given quantity of quinaldine ethiodide and that the con-siderable yield of crude product consisted chiefly of impurities. The method is said to be equally applicable to the more soluble methiodide but when this was used in order that the directions might be followed exactly the yield of pure carbocyanine was not more than 10%.In the second synthesis (Hamer J. 1923 123, 246) methylenediquinaldine dialkylhalide was prepared from quinaldine alkylhalide and formaldehyde according to the equation : The action of alkali in presence of quinoline alkylhalide elimin-ated halogen acid with apparently simultaneous removal of two hydrogen atoms since carbocyanine (I) was directly formed. This synthesis proves the existence of a three-carbon chain joining the quinoline nuclei of the carbocyanine molecule and is unequivocal except for the unexplained fact that the presence of quinoline alkylhalide is necessary. The converse transformation of carbocyanine into methylene-diquinaldine dialkylhalide has now been accomplished thus clearly demonstrating the relationship.The addition of hydriodic acid (b. p. 126”) to 1 1’-dirnethylcarbocyanine iodide gave yellow crystals too unstable to isolate for analysis but doubtless pos-sessing formula 11 which only requires addition of two hydrogen a toms to represent met h ylenediqu inaldine dime t hio dide . This reduction was brought about by heating with excess of hydriodic acid at a carefully regulated temperature and a 78% yield of methylenediquinaldine dimethiodide was the result. Simi-larly 1 1‘-diethylcarbocyanine iodide and 6 6’-dimethyl-1 1‘-diethylcarbocyanine iodide were reduced to methylenediquinaldine diethiodide and 6 6’-dimethylmethylenediquinaldine diethiodide, respectively.The temperature is an important factor in th HAMER REDUCTION O F THE CARBOCYANINES. 213 reduction since with a lowering of a few degrees unchanged carbo-cyanine remains whilst too high temperatures lead to decomposition of the dialkylhalide. p-Dimethylaminobenzylidenequinaldine ethiodide was similarly heated with hydriodic acid but analysis of the product proved that, besides reduction of the ethylenic linking the two methyl groups had been replaced by hydrogen atoms. That the compound was p-aminobenzylquinaldine ethiodide and not the hydriodide of p-dimethylaminobenzylidenequinaldine was established by the fact that it was neutral and unattacked by ammonia. F x P E R I M E N T A L. Preparation of 1 1'-Dimethylcarbocyanine Iodide by Use of Cirthoformic Ester (compare Konig loc.cit .).-Quinaldine methiodide (6 g.) was boiled with acetic anhydride (60 c.c. b. p. 135-140"), and during 5 minutes orthoformic ester (2.1 g. b. p. 142-146") was added. The mixture was concentrated to half volume and the solid removed when cold. The greater part of the impurity was extracted by boiling methyl alcohol (15 c.c.) and the undissolved crude carbocyanine was recrystallised from methyl alcohol (yield 67; instead of 50). The method recommended in a later paper (Ber. 1924 57 685) gave a 10% yield. Reduction of 1 1 '-Dimethylcarbocyaizine Iodide.-By heating the carbocyanine (1.5 g . ) with hydriodic acid (10 c.c. b. p. 126") in a sealed tube a t 182-185" for 6 hours black crystals of periodide were produced; addition of water gave a yellow precipitate.The total solid was suspended in boiling 1.5% hydrochloric acid and sulphur dioxide passed in until a clear solution was obtained when potassium iodide was added (1.5 g.). The product (yield 780/) mas recrystallised from dilute hydrochloric acid with charcoal treatment and addition of potassium iodide. The crystals were ground with pyridine (5 c.c.) to remove any acid impurity (see below) washed with acetone recrystallised from absolute alcohol, and dried in the steam-oven (Found C = 47.27; H = 4-19: I = 43.41. Calc. for C2,H2,N,T2 C = 47.42; H = 4.16; I = 43.617;) ; m. p. 20'7" (decornp.) alone or mixed with methylene-diquinaldine dimethiodide. The compound had the properties of this substance and its crystallisation could be started by inoculation with it.By reduction of the carbocyanine a t 203-209" the iodide obtained after two recrystallisations from absolute alcohol was strongly acid ; it appeared to be free from methylenediquinaldine dimethiodide since it was completely and easily soluble in cold pyridine in which the dimethiodide is practically insoluble 214 HAMER REDUCTION OF THE CARBOCYANINES. Reduction of 1 1'-Diethylcarbocyanine Halide.-The iodide or bromide (1 g.) was heated with hydriodic acid (7 c.c.) at 178-181" and on reduction of the resultant periodide the crystalline product (yield 76%) was almost pure (Found I = 41.27y0). It was treated with pyridine and recrystallised from absolute alcohol (yield 54%). This reduction product methylenediquinaldine diethiodide and their mixture melted simultaneously a t 205" (decomp.).For analysis it was dried in the steam-oven (Found : C = 48.80; H = 4.73; I = 41.62. Calc. for C25H28N212 C = 49.18; H = 4.63; I = 41-61y0). Reduction of 6 6'-Dimethyl-1 1 '-diethylcarbocyanine Iodide.-Hydriodic acid (5 c.c.) and the carbocyanine (0.5 g.) [fine needles of the almost colourless hydriodide formed] were heated a t 178-185" for 5 hours and the solid was treated with sulphur dioxide as in other cases (yield 83%). For analysis the iodide was dried over sulphuric acid and soda-lime (Found I = 38-97. Calc. for C,,H,,N21,,H,0 I = 38.68%). It melted at 219" alone or mixed with 6 6'-dimethylmethylenediquinaldine diethiodide. The m. p. was unaltered by recrystallisation.Reduction of p-Dimethylaminobenxylidenequinaldine Ethiodide.-This was prepared by the method of Konig and Treichel ( J . pr. Chenx. 1921 [ii] 102 63). By increasing the time of heating from 1 hour to 24 hours the yield of recrystallised product was raised from 23 to 76% (Found I = 29.33; calc. 29.51%); m. p. 259-263" (decomp.). p-Dimethylaminobenzylidenequinaldine ethiodide ( 1 -5 g.) and hydriodic acid (10 c.c.) were heated for 3 hours at 178-181" water was added and the solid in boiling dilute hydrochloric acid treated with sulphur dioxide. The clear solution gave no precipitate with potassium iodide (1.5 g.) but ammonia produced an orange ta,r which hardened and was powdered filtered and dried in a vacuum desiccator. From absolute alcohol it separated as clear red crystals (yield 59%). A thrice recrystallised specimen was dried in a vacuum desiccator and was shown by analysis to be p-aminobenzyl-quinaldine ethiodide (Found C = 56.64 ; H = 5.26 ; N = 7.08 ; I = 31.30. CI9H,,N,I requires C = 56.41 ; H = 5-24 ; N = 6-93 ; I = 31.41y0). It is moderately soluble in alcohol or water ; m. p. 200-201" with incipient softening a couple of degrees lower. UNIVERSITY CREMICAL LABORATORY CAMBRIDGE. DAVY FARADAY RESEARCH LABORATORY ROYAL INSTITUTION. [Received November 22nd 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700211

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

SHAM- FISSIOK O F THE PYRIDINE KUCLEUY ETC. PART 11. 21s XXXV1.-Fission of the Pyridine Nucleus during Reduction. Part IP. The Preparation of Glutar-diald oxirne. By BRIAN DUNCAN SHAW. THE suggestion (J. 1924 125 3041) that the initial product of the action of sodium and alcohol on pyridine is 1 4-dihydropyridine has now been confirmed for although this has not been isolated, if the solution is treated with hydroxylamine ammonia is evolved, and a good yield (700/6) of glutaraldehydedioxime obtained. This value is obviously too low since some of the dihydro-compound is further reduced. The initial reduction product therefore is largely if not entirely 1 4-dihydropyridine. Further work on glutardialdehyde and its homologues is in progress. E x P E R I M E N T A L.Pyridine b. p. 115-116" was heated a t SO" with 4% potassium permanganate solution until a pink colour persisted. The purified base was separated by distillation dried over caustic soda and boiled with powdered calcium carbide. The alcohol was boiled with powdered calcium carbide and fractionated through a column filled with freshly-broken lumps of the same material. GZutardiald0xime.-No ammonia was evolved when pyridine (SO g.) in boiling alcohol (400 c.c.) was treated with sodium (24 g.). Hydroxylamine hydrochloride (36 9.) in dry alcohol was added, and the mixture boiled for a few minutes when ammonia was evolved copiously. The remainder of the sodium was precipitated by addition of the requisite quantity of hydrochloric acid diluted with alcohol. After 2 hours' boiling the sodium chloride was removed and the filtrate distilled until only SO C.C.remained. The oxime separated slowly and a further quantity was obtained from the mother-liquor (yield 28 g. or 65% calculated on the hydroxyl-amine); rn. p. 175" after recrystallisation from water or pyridine. It may be sublimed without decomposition. Its identity was established by analysis (Found N = 21.2; calc. 21-05°/0) by its reactions and by reduction to pentamethylenediamine (some piperidine was also produced). Boiling with hydrochloric acid gave pyridine (compare Braun and Danziger Ber. 1913 46 103). When amyl alcohol was used for the reduction little hydrogen was evolved and the yield calculated on the assumption that the sodium liberated the theoretical quantity of hydrogen and that only 1 4-dihydropyridine was produced varied from 68-72016.Excess of hydroxylamine was used in these cases 216 SPENCER : Glutardialdehyde was obtained from the oxime by the method used by Harries in the case of succindialdehyde. Both the glass-like polymeride and the unimolecular form described by Harries a,nd Tank (Ber. 1908 41 1705) were obtained. Part of this work was carried out a t University College Notting-ham. The author is indebted to Professor F. S. Kipping F.R.S., for his kindness during that period to the Department of Scientific and Industrial Research for a maintenance grant and to the South Metropolitan Gas Company for the supply of pyridine. EAST LONDON COLLEGE, UNIVERSITY OF LONDON. [Received November 19th 1924.SHAM- FISSIOK O F THE PYRIDINE KUCLEUY ETC. PART 11. 21s XXXV1.-Fission of the Pyridine Nucleus during Reduction. Part IP. The Preparation of Glutar-diald oxirne. By BRIAN DUNCAN SHAW. THE suggestion (J. 1924 125 3041) that the initial product of the action of sodium and alcohol on pyridine is 1 4-dihydropyridine has now been confirmed for although this has not been isolated, if the solution is treated with hydroxylamine ammonia is evolved, and a good yield (700/6) of glutaraldehydedioxime obtained. This value is obviously too low since some of the dihydro-compound is further reduced. The initial reduction product therefore is largely if not entirely 1 4-dihydropyridine. Further work on glutardialdehyde and its homologues is in progress. E x P E R I M E N T A L.Pyridine b. p. 115-116" was heated a t SO" with 4% potassium permanganate solution until a pink colour persisted. The purified base was separated by distillation dried over caustic soda and boiled with powdered calcium carbide. The alcohol was boiled with powdered calcium carbide and fractionated through a column filled with freshly-broken lumps of the same material. GZutardiald0xime.-No ammonia was evolved when pyridine (SO g.) in boiling alcohol (400 c.c.) was treated with sodium (24 g.). Hydroxylamine hydrochloride (36 9.) in dry alcohol was added, and the mixture boiled for a few minutes when ammonia was evolved copiously. The remainder of the sodium was precipitated by addition of the requisite quantity of hydrochloric acid diluted with alcohol.After 2 hours' boiling the sodium chloride was removed and the filtrate distilled until only SO C.C. remained. The oxime separated slowly and a further quantity was obtained from the mother-liquor (yield 28 g. or 65% calculated on the hydroxyl-amine); rn. p. 175" after recrystallisation from water or pyridine. It may be sublimed without decomposition. Its identity was established by analysis (Found N = 21.2; calc. 21-05°/0) by its reactions and by reduction to pentamethylenediamine (some piperidine was also produced). Boiling with hydrochloric acid gave pyridine (compare Braun and Danziger Ber. 1913 46 103). When amyl alcohol was used for the reduction little hydrogen was evolved and the yield calculated on the assumption that the sodium liberated the theoretical quantity of hydrogen and that only 1 4-dihydropyridine was produced varied from 68-72016. Excess of hydroxylamine was used in these cases 216 SPENCER : Glutardialdehyde was obtained from the oxime by the method used by Harries in the case of succindialdehyde. Both the glass-like polymeride and the unimolecular form described by Harries a,nd Tank (Ber. 1908 41 1705) were obtained. Part of this work was carried out a t University College Notting-ham. The author is indebted to Professor F. S. Kipping F.R.S., for his kindness during that period to the Department of Scientific and Industrial Research for a maintenance grant and to the South Metropolitan Gas Company for the supply of pyridine. EAST LONDON COLLEGE, UNIVERSITY OF LONDON. [Received November 19th 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700215

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

216 SPENCER : XXXVI1.-The Action of Bromine on Sodium and Silver A xides. By DOUGLAS ARTHUR SPENCER. Part I . Bromoamimide. DURING the course of experiments suggested by Professor H. B. Baker aiming a t the preparation of triatomic nitrogen bromine vapour diluted with nitrogen was passed over sodium azide. The colour of the gaseous mixture faded considerably but was not completely discharged however long the bromine remained in contact with the azide and the gas leaving the apparatus had a pungent but sickly smell reminiscent of hydrazoic acid and dilute bromine vapour. An aqueous solution of the gas was yellow gave a blood-red coloration with ferric chloride smelled of hypobromous and hydr-azoic acids and slowly evolved nitrogen on standing. Preliminary attempts to freeze out any compound formed resulted in violent explosions which occasionally detonated the sodium azide.The dilute gas mixture is itself extremely sensitive to shock or rise of temperature the explosion being accompanied by a flash of livid blue light whilst the glass parts of the apparatus are reduced to powder. The analysis was therefore performed indirectly as follows : Pure carbon dioxide generated by the action of boiled-out hydro-chloric acid on calcite was washed with sodium bicarbonate and dried by sulphuric acid and phosphorus pentoxide and was used to carry bromine vapour (derived from the liquid a t 5") over a large surface of sodium azide contained in a glass tube 175 cm. long and 0.5 cm. in diameter coiled into a spiral and kept a t 0" THE ACTION OF BROMINE ON SODIUM AXD SILVER AZIDES.217 The gas current was adjusted to carry about 0.05 g. of bromine over the azide per hour. The pale yellow gas so obtained was passed throcgh a hard glass tube 10 em. long packed with glass fragments and heated a t the far end by a small bunsen flame. By this means, the compound was decomposed without explosion and the gas acquired the much darker red colour characteristic of bromine vapour. The products of decomposition were passed over silver leaf into a potash nitrometer the carbon dioxide stream being stopped when the volume of gas in the latter had remained constant for 4 hour. The volume of this gas which was pure nitrogen having the normal density was measured over water and reduced t o that a t S.1'.P.The excess of silver leaf was dissolved in nitric acid and the silver bromide determined gravimetrically. The results are tabulated below. TABLE I. Expt. NO. 1 2 3 4 3 fi 7 Duration in hours. t 2 Bromine Bromine C.C. of N2 aken (g.). recovered (g.). obtained. 0.1684 0.1247 37.07 0-3938 0.2128 74.10 - 0.1549 57.60 0.1 !)3 5 0*09447 36.00 0.1 701 0.0802 25.80 O*BDOti 0.1324 50.00 0.3833 0.1706 GI*& IS3 Rr,. X. 1.41 1.26 1.13 1.11 1.14 1.13 1.15 Excluding the results of experiments 1 and 2 in which the bromine vapour was in contact with the azide for a comparatively short period the mean value is N3 Brl.13. Whilst pointing t o the presence of brornoaxoimide N,Br the analyses show that there is about 8% more bromine in the gas than is required by the simple formula.Since the quantity of bromine recovered agrees with that required by the equation Na" + Br = NaBr + N,Br it was a t first thought that this excess was due to a deficiency in the volume of nitrogen obtained, but the density viscosity and chemical behaviour of the nitrogen were normal and therefore it is improbable that any polymeric modification was present even if it could have survived the heating. A second possibility was that the reaction was reversible or incom-plete but alterations in the temperature of tlhe reaction tube, and of the time of contact of the bromine with the sodium azide, did not materially affect the final analysis. The formation of some other nitrogen bromide e.g. NBr, was a third possibility.By using a fine capillary tube as connecting link between the reaction tube and condensing vessels any explosion could be localised, and by immersing these vessels in freezing mixtures kept in un-silvered Dewar flasks standing in large beakers of water rendered less dangerous. It then became possible to freeze the substanc 218 SPENCER : out and to fractionate it by passing a stream of nitrogen over the surface whilst allowing the temperature to rise. The analysis of these fractions was carried out as follows The vapour derived from each fraction was absorbed in standardised solutions of carbonate-free caustic soda containing hydrogen peroxide. With this mixture the compound forms sodium azide and sodium bromide the hydrogen peroxide reducing the sodium hypobromite first formed : N3Br + 2NaOH = NaBrO + NaN3 + H,O.NaBrO + H,O = NaBr + H,O + 0,. By titrating the excess of sodium hydroxide with N/10-sulphuric acid and phenolphthalein the amount of alkali required to combine with the N3 and Br radicals was found. A known excess of silver nitrate was then added silver bromide and azide being precipitated. The mixture was boiled with nitric acid until all the silver azide had been decomposed and the hydrazoic acid driven off. The cooled solution was titrated with ammonium thiocyanate giving a measure of the silver nitrate required to precipitate the bromide present.* The results are summarised in Table 11. TABLE 11. Expt. Fraction. 1 1st 2nd 2 1st 2nd 3 1st 2nd 3rd a. 91.80 84.70 117-9 58.55 29.04 52.17 90-51 b .48-30 43.70 58-06 32.71 14.73 27.19 50.67 t . -loo + 5 - 18 + 5 - 20 - 10 + 5 N Rr,. 1.06 1.07 0.97 1.26 1.036 1.09 1.18 X. a = C.C. of N/lO-NaOH neutralised = N3 + Br; b = C.C. of NIlO-AgNO required to neutralise Br ; t = temperature below * The above procedure provides a method for the estimation of soluble azides in presence of halides which has decided advantages over the gravi-metric determination (Dennis and Isham J . Amer. Chem. SOC. 1907 29, 18). Owing to the number of operations involved and the appreciable solubility of silver azide at normal temperatures the latter method is tedious and liable t o error the results being usually low. On the other hand the volumetric method-titration with silver nitrate followed by treatment with nitric acid and thiocyanate-is both rapid and trustworthy if the solution is first rendered barely acid by the addition of sodium acetate and acetic acid.If potassium arsenate is used as indicator in the first titration, the fhal acid solution is colourless. The colour of silver arsenate is however, not so intense as that of the chromate and quite accurate results may be obtained with the latter. Owing to the solution being slightly acid with acetic acid a small amount of dichromate is formed and the solution is of a yellow-orange colour rather than the usual bright yellow and the use of a comparison basin is advisable THE ACTION OF BROMIXE ON SODIUM AND SILVER AZIDES. 219 which the fraction was obtained.C.C. of NIlO-NaOH equivalent to N3 = a - b. The first fractions (with a mean value of N3 Brl.02) were dark orange-red liquids which solidified at about -45" to dark red solids. The later fractions were ruby red but even these were distinctly lighter and apparently much more mobile than liquid bromine. I f the high bromine content is due to the presence of free bromine, it should be possible to remove this by treating the liquid with sodium azide. A first fraction obtained at -15" was distilled on to sodium azide kept a t -25". The colour of the liquid was not altered even after 3 hours' contact (Pound N Br 04). Also when gas derived directly from the apparatus and of approximate composition N3Br1.13 (see Table I) was condensed on to sodium azide and after 3 hours the liquid was allowed to vaporise the proportions were N3 BrlSl6.The excess of bromine therefore is not present in the free state and the most probable explanation is that it is in the form of nitrogen tribromide NBr,. When the gas was passed into water the solution contained in addition to hydrazoic and hypobromous acids traces of ammonium salts. This cannot however be taken as a proof of the presence of NBr3, for Hantzsch states that iodoazoimide (triazo iodide) gives rise t o a small quantity of ammonia on hydrolysis (compare L. Spiegel, '' Der Stickstoff," 1903 pp. 35 36). Hantzsch (Ber. 1900 33 522) by the interaction of silver azide (but not potassium azide) and iodine in ether solution a t 0" and evaporation of the ether obtained red crystals of the highly unstable iodoazoimide N31 (which he states is probably colourless when pure).A freshly prepared aqueous solution is neutral towards litmus and starch but hydrolyses fairly rapidly to hydrazoic and hypoiodous acids. I n non-aqueous solvents the compound slowly decomposes to iodine and nitrogen. When either sodium or silver azide is treated with bromine dis-solved in ether benzene or ligroin bromoazoimide is formed, but the method is not a convenient one. The bromine attacks the solvent to a certain extent and owing t o the great solubility and volatility of bromoazoimide it is impossible to separate it from the solvent. Moreover the presence of traces of water results in the immediate hydrolysis of the compound to hydrazoic and hypobromous acids.This is most striking in the case of silver azide-bromine mixtures as the admission of a drop of water results in a vigorous evolution of nitrogen due to the rapid reaction of the hypobromous acid a t once produced with the silver azide. Properties of Bromoaxoimide.-The purest sample of the bromide obtained in these experiments was a mobile very volatile orange 220 SPENCER : red liquid which changed to a dark red solid a t about -45". The pungent vapour has toxicological properties similar to hydrazoic acid causing giddiness headache and a slackening of the muscles when inhaled. Traces of the vapour irritate the eyes and cause a slight difficulty in breathing due apparently to congestion of the nasal mucous membrane. Solid liquid and vapour are as sensitive to shock as iodoazo-imide the explosion (often apparently spontaneous) being accom-panied by a flash of livid blue light.Some idea of the instability of the compound even a t -200" may be gathered from the fact that of twenty-four attempts a t freezing the compound and deter-mining its melting point only six were completed without explosion. Fortunately in the majority of cases the sphere of action was limited to a radius of about 3 feet. Within this radius all glass apparatus was reduced to powder ; beyond it a reinforced glass screen proved a sufficient protection. The liquid explodes in contact with phos-phorus arsenic sodium and silver foil but the vapour when diluted with nitrogen and passed over silver leaf or sodium gives a film of the corresponding azide and bromide.The liquid is apparently miscible in all proportions with ether, but is less soluble in benzene or ligroin. These solutions are stable for a few hours in the dark but when concentrated are liable to explode on shaking and on standing gradually decompose giving nitrogen and bromine the latter attacking the solvent. When passed into water bromoazoimide hydrolyses instantaneously, giving a mixture of hydrazoic and hypobromous acids and the solution on standing evolves nitrogen by the interaction of these acids. When bromoazoimide is passed into potassium iodide solution iodine is liberated equivalent to the hypobromous acid produced and potassium azide is obtained : N,Br + 2IZI = KN + KBr + I,. This experiment was performed by substituting a potassium iodide absorption vessel for the heated glass decomposition tube in the apparatus described on p.216 and it is possibly significant that 6 C.C. of nitrogen collected in the nitrometer. Some of this nitrogen may have been due to a slight decomposition of the bromoazoimide into its elements before it reached the absorption vessel but in view of the fact that no free bromine was detected when the compound was distilled on to sodium azide (p. 219), this does not seem probable. It is thought therefore that the nitrogen may have been derived from NBr present THE ACTION O F BROMINE ON SODIUM AND SILVER AZIDES. 221 Part I I . Since bromoazoimide is instantly hydrolysed by water the reaction in aqueous solution between bromine and sodium azicle should yield hydrazoic and hypobromous acids and therefore should differ from that between iodine and sodium or potassium azide which occurs only in presence of sulphur compounds yielding nitrogen (Raschig Chenz.Ztg. 1908 32 1203; Browne J . Amer. Chem. Xoc. 1922 44 2106). When sodium azide solution mas added to N/lO-bromine water, the colour of the mixture faded a t once to a pale straw-yellon- and nitrogen was evolved a t a rate depending on the concentration, temperature and proportions of the solutions. Approximately F I G . 1. 94% of the expected volume of nitrogen was evolved in 15 hours from concentrated solutions a t the ordinary temperature. The gas was contaminated with oxygen hydrazoic acid and hypo-bromous acid. The course of the reaction with various proportions and conceii-trations of the reactants can conveniently be followed by plotting the fall in iodine value of the solution against time.Aliquot portions of the eEervescing solution removed a t fixed intervals were added to potassium iodide and the iodine liberated by the hypobromous acid was titrated with X/lO-sodium arsenite (thiosulphate is unsuitable as it causes an instantaneous liberation of all the available nitrogen. In the figure typical curves obtained with it'/lO-solutions a t 15" are plotted. Hypobromous acid reacts somen7hat slowly x-ith hydrazoic acid, Rrowne Zoc. c i f . ) 222 SPENCER : but rapidly with sodium azide solutions (the latter are always alkn-line by hydrolysis and sodium hypobromite is dissociated to a greater extent than hypobromous acid).Curves 1 and 2 correspond therefore to the slow fall in concentration of hypobromous acid with hydrazoic acid and curves 3 and 4 to the fall in the presence of an excess of sodium azide. An abrupt change in the slope of the curves occurs when one uses more than one equivalent of sodium azide to two of bromine. NaN + Br + H,O = NaBr + HN + HBrO . (1) HBrO + 2HN3 = HBr + H,O + 3N2 - (2) Since one equivalent of hypobromous acid can decompose two equivalents of hydrazoic acid there is in the solution sufficient hypobromous acid to decompose a further equivalent of sodium azide :-HBrO + 2NaN = NaBr + NaOH + 3N . - (3) Equivalent proportions of sodium azide solution and bromine After 17 hours gas evolution had ceased and water were mixed.the solution was colourless and exactly neutral :-NaN + Br + H20 = NaBr + HBrO + HN . a (1) NaN + HBrO + HN = NaBr + H20 + 3N2 (4) . One equivalent of sodium azide was mixed with two equivalents of bromine water. The effervescence was much slower resembling that obtained when mixtures of hydrazoic and hypobromous acids react in presence of sodium bromide. NaN3 + Brz + H,O = NaBr + HBrO + HN (1) HN + &HBrO = $HBr + *H2O + l*Nz . - (2) . The solution should therefore contain equal parts of hydro-bromic and hypobromous acids amounting to one equivalent a t the conclusion of the experiment. The nitrogen evolved would be expected to carry away the greater part of these volatile acids and yet after 17 hours the solution still contained a little more than a quarter of an equivalent of acid one-half of which consisted of hypobromous acid the other half being presumably hydrobromic acid since there was only the slightest trace of azoimide.The Reaction between Bromine Water and Silver Axide.-Silver azide precipitated from a solution of sodium azide slightly acidified with nitric acid was washed until free from soluble silver salts and treated with freshly-prepared bromine water. A vigorou THE ACTION OF BROMINE ON SODIUM AND SILVER AZIDES. 223 reaction took place and silver bromide was obtained (in daylight, the yellow precipitate a t once commenced to turn slate-blue unless excess of bromine was present). The evolved gas contained traces of azoimide together with about 1% of oxygen but no nitrogen oxides and after drying with lime and phosphorus pentoxide had the density of ordinary nitrogen.About 920/o of the nitrogen expected from the equation 2AgN3 + Br = 2AgBr + 3N was obtained within 10 minutes of the mixing butl the presence of hydrazoic acid and oxygen suggests that the side reaction AgN + Br = AgBr + N,Br probably occurs in a manner analogous t o the formation of iodoazoimide (Hantzsch Zoc. cit.). The bromoazoimide was instantly hydrolysed by the water the oxygen being derived by decomposition of the hypobromous acid thus produced (compare Fleury C'ompt. rend. 1920 171 037). The formation of hydr-azoic acid in this manner accounts for the deficiency in nitrogen, as azoimide is only slowly attacked by hypobromous acid; the latter moreover reacts very rapidly with silver azide.Summary. In t h e absence of water bromine reacts with sodium and silver azides to give the highly unstable bronioazoimide : XN + Br = XBr + N,Br. This compound (m. p. about -45") whilst resembling iodoazo-imide in its general properties differs in its greater volatility and immediate decomposition by water. Bromine water reacts instantly with sodium azide solutions to give a mixture of hydrazoic and hypobromous acids which then interact to produce nitrogen. When the sodium azide is present in larger quantities than are required by the equation NaN + Br + H,O = NaBr + HN + HBrO the nitrogen evolution is more rapid owing to the interaction of the hypobromous acid with the excess of sodium azide and it is for this reason that two equivalents of bromine are able to decompose two equivalents of sodium azide.The reaction between silver azide and bromine water differs from that with iodine solutions in that it is better represented by the equation 2AgN + Br = 2AgBr -1 3N,. The only evidence for the momentary existence of bromoazo-imide in aqueous solution is the formation of a certain amount of azoimide with conscquent loss of free nitrogen. The density or viscosity of all nitrogen samples was determined 224 MILLER AND SMILES : but no indication of the existence of the polymeride N3 was obtained. My thanks are due to Professor H. B. Baker at whose suggestion, IMPERIAL COLLEGIZ OF SCIENCE AND TECHNOLOGY, and under whose supervision the work has been carried out.LONDON S.W. 7. [Received November 15th 1924. 216 SPENCER : XXXVI1.-The Action of Bromine on Sodium and Silver A xides. By DOUGLAS ARTHUR SPENCER. Part I . Bromoamimide. DURING the course of experiments suggested by Professor H. B. Baker aiming a t the preparation of triatomic nitrogen bromine vapour diluted with nitrogen was passed over sodium azide. The colour of the gaseous mixture faded considerably but was not completely discharged however long the bromine remained in contact with the azide and the gas leaving the apparatus had a pungent but sickly smell reminiscent of hydrazoic acid and dilute bromine vapour. An aqueous solution of the gas was yellow gave a blood-red coloration with ferric chloride smelled of hypobromous and hydr-azoic acids and slowly evolved nitrogen on standing.Preliminary attempts to freeze out any compound formed resulted in violent explosions which occasionally detonated the sodium azide. The dilute gas mixture is itself extremely sensitive to shock or rise of temperature the explosion being accompanied by a flash of livid blue light whilst the glass parts of the apparatus are reduced to powder. The analysis was therefore performed indirectly as follows : Pure carbon dioxide generated by the action of boiled-out hydro-chloric acid on calcite was washed with sodium bicarbonate and dried by sulphuric acid and phosphorus pentoxide and was used to carry bromine vapour (derived from the liquid a t 5") over a large surface of sodium azide contained in a glass tube 175 cm.long and 0.5 cm. in diameter coiled into a spiral and kept a t 0" THE ACTION OF BROMINE ON SODIUM AXD SILVER AZIDES. 217 The gas current was adjusted to carry about 0.05 g. of bromine over the azide per hour. The pale yellow gas so obtained was passed throcgh a hard glass tube 10 em. long packed with glass fragments and heated a t the far end by a small bunsen flame. By this means, the compound was decomposed without explosion and the gas acquired the much darker red colour characteristic of bromine vapour. The products of decomposition were passed over silver leaf into a potash nitrometer the carbon dioxide stream being stopped when the volume of gas in the latter had remained constant for 4 hour. The volume of this gas which was pure nitrogen having the normal density was measured over water and reduced t o that a t S.1'.P.The excess of silver leaf was dissolved in nitric acid and the silver bromide determined gravimetrically. The results are tabulated below. TABLE I. Expt. NO. 1 2 3 4 3 fi 7 Duration in hours. t 2 Bromine Bromine C.C. of N2 aken (g.). recovered (g.). obtained. 0.1684 0.1247 37.07 0-3938 0.2128 74.10 - 0.1549 57.60 0.1 !)3 5 0*09447 36.00 0.1 701 0.0802 25.80 O*BDOti 0.1324 50.00 0.3833 0.1706 GI*& IS3 Rr,. X. 1.41 1.26 1.13 1.11 1.14 1.13 1.15 Excluding the results of experiments 1 and 2 in which the bromine vapour was in contact with the azide for a comparatively short period the mean value is N3 Brl.13. Whilst pointing t o the presence of brornoaxoimide N,Br the analyses show that there is about 8% more bromine in the gas than is required by the simple formula.Since the quantity of bromine recovered agrees with that required by the equation Na" + Br = NaBr + N,Br it was a t first thought that this excess was due to a deficiency in the volume of nitrogen obtained, but the density viscosity and chemical behaviour of the nitrogen were normal and therefore it is improbable that any polymeric modification was present even if it could have survived the heating. A second possibility was that the reaction was reversible or incom-plete but alterations in the temperature of tlhe reaction tube, and of the time of contact of the bromine with the sodium azide, did not materially affect the final analysis.The formation of some other nitrogen bromide e.g. NBr, was a third possibility. By using a fine capillary tube as connecting link between the reaction tube and condensing vessels any explosion could be localised, and by immersing these vessels in freezing mixtures kept in un-silvered Dewar flasks standing in large beakers of water rendered less dangerous. It then became possible to freeze the substanc 218 SPENCER : out and to fractionate it by passing a stream of nitrogen over the surface whilst allowing the temperature to rise. The analysis of these fractions was carried out as follows The vapour derived from each fraction was absorbed in standardised solutions of carbonate-free caustic soda containing hydrogen peroxide. With this mixture the compound forms sodium azide and sodium bromide the hydrogen peroxide reducing the sodium hypobromite first formed : N3Br + 2NaOH = NaBrO + NaN3 + H,O.NaBrO + H,O = NaBr + H,O + 0,. By titrating the excess of sodium hydroxide with N/10-sulphuric acid and phenolphthalein the amount of alkali required to combine with the N3 and Br radicals was found. A known excess of silver nitrate was then added silver bromide and azide being precipitated. The mixture was boiled with nitric acid until all the silver azide had been decomposed and the hydrazoic acid driven off. The cooled solution was titrated with ammonium thiocyanate giving a measure of the silver nitrate required to precipitate the bromide present.* The results are summarised in Table 11. TABLE 11.Expt. Fraction. 1 1st 2nd 2 1st 2nd 3 1st 2nd 3rd a. 91.80 84.70 117-9 58.55 29.04 52.17 90-51 b . 48-30 43.70 58-06 32.71 14.73 27.19 50.67 t . -loo + 5 - 18 + 5 - 20 - 10 + 5 N Rr,. 1.06 1.07 0.97 1.26 1.036 1.09 1.18 X. a = C.C. of N/lO-NaOH neutralised = N3 + Br; b = C.C. of NIlO-AgNO required to neutralise Br ; t = temperature below * The above procedure provides a method for the estimation of soluble azides in presence of halides which has decided advantages over the gravi-metric determination (Dennis and Isham J . Amer. Chem. SOC. 1907 29, 18). Owing to the number of operations involved and the appreciable solubility of silver azide at normal temperatures the latter method is tedious and liable t o error the results being usually low.On the other hand the volumetric method-titration with silver nitrate followed by treatment with nitric acid and thiocyanate-is both rapid and trustworthy if the solution is first rendered barely acid by the addition of sodium acetate and acetic acid. If potassium arsenate is used as indicator in the first titration, the fhal acid solution is colourless. The colour of silver arsenate is however, not so intense as that of the chromate and quite accurate results may be obtained with the latter. Owing to the solution being slightly acid with acetic acid a small amount of dichromate is formed and the solution is of a yellow-orange colour rather than the usual bright yellow and the use of a comparison basin is advisable THE ACTION OF BROMIXE ON SODIUM AND SILVER AZIDES.219 which the fraction was obtained. C.C. of NIlO-NaOH equivalent to N3 = a - b. The first fractions (with a mean value of N3 Brl.02) were dark orange-red liquids which solidified at about -45" to dark red solids. The later fractions were ruby red but even these were distinctly lighter and apparently much more mobile than liquid bromine. I f the high bromine content is due to the presence of free bromine, it should be possible to remove this by treating the liquid with sodium azide. A first fraction obtained at -15" was distilled on to sodium azide kept a t -25". The colour of the liquid was not altered even after 3 hours' contact (Pound N Br 04). Also when gas derived directly from the apparatus and of approximate composition N3Br1.13 (see Table I) was condensed on to sodium azide and after 3 hours the liquid was allowed to vaporise the proportions were N3 BrlSl6.The excess of bromine therefore is not present in the free state and the most probable explanation is that it is in the form of nitrogen tribromide NBr,. When the gas was passed into water the solution contained in addition to hydrazoic and hypobromous acids traces of ammonium salts. This cannot however be taken as a proof of the presence of NBr3, for Hantzsch states that iodoazoimide (triazo iodide) gives rise t o a small quantity of ammonia on hydrolysis (compare L. Spiegel, '' Der Stickstoff," 1903 pp. 35 36). Hantzsch (Ber. 1900 33 522) by the interaction of silver azide (but not potassium azide) and iodine in ether solution a t 0" and evaporation of the ether obtained red crystals of the highly unstable iodoazoimide N31 (which he states is probably colourless when pure).A freshly prepared aqueous solution is neutral towards litmus and starch but hydrolyses fairly rapidly to hydrazoic and hypoiodous acids. I n non-aqueous solvents the compound slowly decomposes to iodine and nitrogen. When either sodium or silver azide is treated with bromine dis-solved in ether benzene or ligroin bromoazoimide is formed, but the method is not a convenient one. The bromine attacks the solvent to a certain extent and owing t o the great solubility and volatility of bromoazoimide it is impossible to separate it from the solvent. Moreover the presence of traces of water results in the immediate hydrolysis of the compound to hydrazoic and hypobromous acids.This is most striking in the case of silver azide-bromine mixtures as the admission of a drop of water results in a vigorous evolution of nitrogen due to the rapid reaction of the hypobromous acid a t once produced with the silver azide. Properties of Bromoaxoimide.-The purest sample of the bromide obtained in these experiments was a mobile very volatile orange 220 SPENCER : red liquid which changed to a dark red solid a t about -45". The pungent vapour has toxicological properties similar to hydrazoic acid causing giddiness headache and a slackening of the muscles when inhaled. Traces of the vapour irritate the eyes and cause a slight difficulty in breathing due apparently to congestion of the nasal mucous membrane.Solid liquid and vapour are as sensitive to shock as iodoazo-imide the explosion (often apparently spontaneous) being accom-panied by a flash of livid blue light. Some idea of the instability of the compound even a t -200" may be gathered from the fact that of twenty-four attempts a t freezing the compound and deter-mining its melting point only six were completed without explosion. Fortunately in the majority of cases the sphere of action was limited to a radius of about 3 feet. Within this radius all glass apparatus was reduced to powder ; beyond it a reinforced glass screen proved a sufficient protection. The liquid explodes in contact with phos-phorus arsenic sodium and silver foil but the vapour when diluted with nitrogen and passed over silver leaf or sodium gives a film of the corresponding azide and bromide.The liquid is apparently miscible in all proportions with ether, but is less soluble in benzene or ligroin. These solutions are stable for a few hours in the dark but when concentrated are liable to explode on shaking and on standing gradually decompose giving nitrogen and bromine the latter attacking the solvent. When passed into water bromoazoimide hydrolyses instantaneously, giving a mixture of hydrazoic and hypobromous acids and the solution on standing evolves nitrogen by the interaction of these acids. When bromoazoimide is passed into potassium iodide solution iodine is liberated equivalent to the hypobromous acid produced and potassium azide is obtained : N,Br + 2IZI = KN + KBr + I,.This experiment was performed by substituting a potassium iodide absorption vessel for the heated glass decomposition tube in the apparatus described on p. 216 and it is possibly significant that 6 C.C. of nitrogen collected in the nitrometer. Some of this nitrogen may have been due to a slight decomposition of the bromoazoimide into its elements before it reached the absorption vessel but in view of the fact that no free bromine was detected when the compound was distilled on to sodium azide (p. 219), this does not seem probable. It is thought therefore that the nitrogen may have been derived from NBr present THE ACTION O F BROMINE ON SODIUM AND SILVER AZIDES. 221 Part I I . Since bromoazoimide is instantly hydrolysed by water the reaction in aqueous solution between bromine and sodium azicle should yield hydrazoic and hypobromous acids and therefore should differ from that between iodine and sodium or potassium azide which occurs only in presence of sulphur compounds yielding nitrogen (Raschig Chenz.Ztg. 1908 32 1203; Browne J . Amer. Chem. Xoc. 1922 44 2106). When sodium azide solution mas added to N/lO-bromine water, the colour of the mixture faded a t once to a pale straw-yellon- and nitrogen was evolved a t a rate depending on the concentration, temperature and proportions of the solutions. Approximately F I G . 1. 94% of the expected volume of nitrogen was evolved in 15 hours from concentrated solutions a t the ordinary temperature. The gas was contaminated with oxygen hydrazoic acid and hypo-bromous acid.The course of the reaction with various proportions and conceii-trations of the reactants can conveniently be followed by plotting the fall in iodine value of the solution against time. Aliquot portions of the eEervescing solution removed a t fixed intervals were added to potassium iodide and the iodine liberated by the hypobromous acid was titrated with X/lO-sodium arsenite (thiosulphate is unsuitable as it causes an instantaneous liberation of all the available nitrogen. In the figure typical curves obtained with it'/lO-solutions a t 15" are plotted. Hypobromous acid reacts somen7hat slowly x-ith hydrazoic acid, Rrowne Zoc. c i f . ) 222 SPENCER : but rapidly with sodium azide solutions (the latter are always alkn-line by hydrolysis and sodium hypobromite is dissociated to a greater extent than hypobromous acid).Curves 1 and 2 correspond therefore to the slow fall in concentration of hypobromous acid with hydrazoic acid and curves 3 and 4 to the fall in the presence of an excess of sodium azide. An abrupt change in the slope of the curves occurs when one uses more than one equivalent of sodium azide to two of bromine. NaN + Br + H,O = NaBr + HN + HBrO . (1) HBrO + 2HN3 = HBr + H,O + 3N2 - (2) Since one equivalent of hypobromous acid can decompose two equivalents of hydrazoic acid there is in the solution sufficient hypobromous acid to decompose a further equivalent of sodium azide :-HBrO + 2NaN = NaBr + NaOH + 3N . - (3) Equivalent proportions of sodium azide solution and bromine After 17 hours gas evolution had ceased and water were mixed.the solution was colourless and exactly neutral :-NaN + Br + H20 = NaBr + HBrO + HN . a (1) NaN + HBrO + HN = NaBr + H20 + 3N2 (4) . One equivalent of sodium azide was mixed with two equivalents of bromine water. The effervescence was much slower resembling that obtained when mixtures of hydrazoic and hypobromous acids react in presence of sodium bromide. NaN3 + Brz + H,O = NaBr + HBrO + HN (1) HN + &HBrO = $HBr + *H2O + l*Nz . - (2) . The solution should therefore contain equal parts of hydro-bromic and hypobromous acids amounting to one equivalent a t the conclusion of the experiment. The nitrogen evolved would be expected to carry away the greater part of these volatile acids and yet after 17 hours the solution still contained a little more than a quarter of an equivalent of acid one-half of which consisted of hypobromous acid the other half being presumably hydrobromic acid since there was only the slightest trace of azoimide.The Reaction between Bromine Water and Silver Axide.-Silver azide precipitated from a solution of sodium azide slightly acidified with nitric acid was washed until free from soluble silver salts and treated with freshly-prepared bromine water. A vigorou THE ACTION OF BROMINE ON SODIUM AND SILVER AZIDES. 223 reaction took place and silver bromide was obtained (in daylight, the yellow precipitate a t once commenced to turn slate-blue unless excess of bromine was present).The evolved gas contained traces of azoimide together with about 1% of oxygen but no nitrogen oxides and after drying with lime and phosphorus pentoxide had the density of ordinary nitrogen. About 920/o of the nitrogen expected from the equation 2AgN3 + Br = 2AgBr + 3N was obtained within 10 minutes of the mixing butl the presence of hydrazoic acid and oxygen suggests that the side reaction AgN + Br = AgBr + N,Br probably occurs in a manner analogous t o the formation of iodoazoimide (Hantzsch Zoc. cit.). The bromoazoimide was instantly hydrolysed by the water the oxygen being derived by decomposition of the hypobromous acid thus produced (compare Fleury C'ompt. rend. 1920 171 037). The formation of hydr-azoic acid in this manner accounts for the deficiency in nitrogen, as azoimide is only slowly attacked by hypobromous acid; the latter moreover reacts very rapidly with silver azide.Summary. In t h e absence of water bromine reacts with sodium and silver azides to give the highly unstable bronioazoimide : XN + Br = XBr + N,Br. This compound (m. p. about -45") whilst resembling iodoazo-imide in its general properties differs in its greater volatility and immediate decomposition by water. Bromine water reacts instantly with sodium azide solutions to give a mixture of hydrazoic and hypobromous acids which then interact to produce nitrogen. When the sodium azide is present in larger quantities than are required by the equation NaN + Br + H,O = NaBr + HN + HBrO the nitrogen evolution is more rapid owing to the interaction of the hypobromous acid with the excess of sodium azide and it is for this reason that two equivalents of bromine are able to decompose two equivalents of sodium azide. The reaction between silver azide and bromine water differs from that with iodine solutions in that it is better represented by the equation 2AgN + Br = 2AgBr -1 3N,. The only evidence for the momentary existence of bromoazo-imide in aqueous solution is the formation of a certain amount of azoimide with conscquent loss of free nitrogen. The density or viscosity of all nitrogen samples was determined 224 MILLER AND SMILES : but no indication of the existence of the polymeride N3 was obtained. My thanks are due to Professor H. B. Baker at whose suggestion, IMPERIAL COLLEGIZ OF SCIENCE AND TECHNOLOGY, and under whose supervision the work has been carried out. LONDON S.W. 7. [Received November 15th 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700216

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

224 MILLER AND SMILES : XXXVII1.-The Constitution of Disulphoxides. Part I I . By CECIL JAMES MILLER and SAMUEL SMILES. ALTHOUGH the symmetrical structure of the disulphoxides (I) has been generally accepted the evidence adduced in its favour has been incorrectly interpreted and is in fact ambiguous and many simple reactions of these substances appear clearly to indicate the thio-sulphonate structure (IT) such for example as their behaviour with zinc dust potassium sulphide sodium arsenite and mer-captans (J. 1924 125 176). Moreover this view is supported by syntheses of disulphoxides from sulphenic halides and silver sul-phinates (Zincke Annalen 1912 391 67). Since all the definite evidence thus favoured the thiosulphonate structure it was concluded that this should not be abandoned but instead should be regarded as the most probable until final proof of one structure or another was forthcoming.(I.) Ar*E*fi*Ar Ar*so,*s*Ar ArR*O*SAr (111. ) 00 (11.1 0 The experiments now described provide the necessary further proof of this unsymmetrical constitution in that (1) the action of Grignard’s reagent with the disulphoxides must be added to those already quoted as indicating this structure (2) the reduction of disulphoxides with hydrogen iodide which hitherto has been quoted as the main evidence for the symmetrical formula is not only use-less as such but accords with the thiosulphonate structure (3) the unsymmetrical character of the disulphoxides is demonstrated by synthesis. slthough the behaviour of numerous carbon compounds of sulphur with alkyl and aryl magnesium halides has been investi-gated (Lapworth J .1912 101 297; Hepworth and Clapham J., 1921 119 IlSS; Wedekind Rer. 1921 54 16041 that of the disulphoxides appears to have escaped attention. These substances are very readily attacked by the magiiesinm compounds and usin THE CONSTITUTION OF DISULPHOXIDES. PART 11. 225 equimolecular proportions of the reactants high yields of the sulphinic acids have been isolated fission of the disulphoxide taking place apparently according to the following scheme (IV) : The sulphinic acid was obtained in every case examined but the fate of the thioaryl group of the disulphoxide varied according to the nature of the magnesium compound used with magnesium inethyl iodide the methyl aryl sulphide Ar*S*CH, was commonly obtained whilst with magnesium phenyl iodide the disulphide and diphenyl also were observed.The chief point at issue is tlhe situation of the oxygen in the molecule of the disulphoxide and with the symmetrical formula it is very difficult to explain the isolation of SOY; of this as sulphinic acid. According to this symmetrical constitution it would be expected that fission of the molecule would result in the formation of a sulphoxide (V) but this has not been observed. The results of this decomposition evidently support the unsymmetrical structure and appear inexplicable on the basis of the symmetrical formula. The mode of experiment is described and the results are tabulated on subsequent pages. The fact that the disulphoxides are easily reduced by hydrogen iodide t o disulphides has been regarded as sufficient reason for rejecting the thiosulphonate structure and as proving the presence of the true disulphoxide arrangement (Hinsberg Ber.1908 41, 2836 4294; 1909 42 1278; Fries Ber. 1914 47 1195). It is assumed that the reduction is direct and since the sulphonyl group usually is not easily reduced by this reagent whilst the thionyl group is readily attacked the conclusion would seem justified but it has been pointed out (Smiles and Gibson J. 1924 125 176) that the force of the argument depends on the assumption that reduction is direct and is not accompanied by fission of the mole-cule. If however rupture does take place the reduction cannot be used as an argument against the unsymmetrical or in favour of the symmetrical formula for in either case a disulphide must be expected as the final product of the reaction.The question whether this fission takes place or not may be answered by the reduction of a disulphoxide containing different aromatic groups. I n such a case, if the unsymmetrical disulphide is the sole product (VI) the assumption of direct reduction is clearly justified but if both or even one of the symmetrical disulphides are obtlained (VII) it must be admitted that rupture of the dithio-system has taken place. (vI.) R1*SO*SO*R2 -+ R1*S-S*R2 (VII.) 2R1*S,0,*R2 -+ (RlS) + (R2S), VOL. CXXVII. 226 MILLER AND SMILES: Disulphoxides containing merent aromatic nuclei are readily prepared by an extension of the synthetical method of Zincke (Zoc.cit.) For example when the silver salts of p-toluenesulphinic acid and p-chlorobenzenesulphinic acid are treated with o-nitrophenyl-sulphur chloride the o-nitrophenyl p-toluenethiolsulp~ona.te (VIII) and o-nitrophenyl p-chlorobenzenethiolsulphonate (IX) are respec-tively 'formed. N02*C,H4*SCI + AgSO,*C,H = AgCl + NO,*C,H,*S*SO,*C,H,. (VIII.) Reduction of these substances with hydrogen iodide in the usual manner (compare Hinsberg Zoc. cit.) furnished o-nitrophenyl di-sulphide (N02*C,H,*S*), in good yield and in the case of the chloro-derivative p-chlorophenyl disulphide also was isolated. Hence it is clear that the disulphoxide system has. been broken during the process of reduction and the reaction cannot be admitted as evidence favouring the symmetrical and excluding the unsymmetrical structure.Nothing else can be deduced from this result but further information has been gained by adopting milder conditions of reduction with hydrogen iodide or by the use of dilute hyposulphite (in presence of sodium carbonate). The derivative (VIII) then yielded p-toluenesulphinic acid and the nitrophenyl disulphide the chloronitro-derivative (IX) gave p-chlorobenzenesulphinic acid and the nitro-disulphide whilst p-tolyl disulphoxide and p-chlorophenyl disulphoxide gave the corresponding sulphinic acids and disulphides or mercaptans. These results are similar to those obtained by Gutmann (Ber. 1914 47 635) on reduction with sodium arsenite. In the cases of disulphoxides containing similar aromatic groups this result does not enable a decision to be made in favour of either structure for both permit the formation of a sulphinic acid by hydrolytic fission, R*SO-SO*R + R*SO,H + R*S*OH + R*SO,*SR whilst the disulphide would result from reduction of the less stable sulphenic acids.Turning to the case of a disulphoxide containing different aromatic groups a distinction between the requirements of either structure is found. On the basis of the symmetrical arrangement the formation of two sulphinic acids may be expected, for there is no reason to suppose that hydrolysis will take place in one direction only when R1 and R2 are of similar character : RlS*OH + R2*S0,H +- R1*SO*SO*R2 -+ R1*S02H + R2*S*OH THE CONSTITUTION OF DISULPHOXIDES. PART 11. 227 On the other hand according to the thiosulphonate structure only one sulphinic acid should be formed : 2R1*S0,*S=R2 + 2R1*S0,H + (SR2)2 The latter condition accords with the result obtained by the reduction of these substances only one sulphinic acid has been isolated in each case examined.Moreover it is significant that the sulphinic acid-isolated was always the one which had been used as ifi component in the synthesis thus nitrophenyl t'oluenethiolsulphonate (VIII) yielded p-toluenesulphinic acid and o-nitrophenyl disulphide, and nitrophenyl chlorobenzenethiolsulphonate (IX) gave p-chloro-benzenesulphinic acid and the nitro-disulphide : 2CsH,C1*S0,*S*C6H4*No2 + 2C6H,C1*S02H + (NO,*C,I~,*S.),. The action of mercaptans with these disulphoxides is closely analo-gous (compare Smiles and Gibson loc.cit.). o-Nitrophenyl mercaptan yields in both cases the o-nitrophenyl disulphide and the corre-ponding sulphinic acid : CiH,.SO,* S-CGH,*NO, H S*CGH,-N02 The information gained from this extended study of the reduction of the disulphoxides therefore clearly favours the unsymmetrical structure. Taking a general review of the characteristic reactions of the disulphoxides it is seen that all yield the sulphinic acid and a product which contains the thioaryl group; these substances result from the action of zinc dust magnesium alkyl halides potass-ium sulphide mercaptans and of arsenite and other mild reducing agents. The majority of these reactions indicate an unsymmetrical structure a few are ambiguous in their import whilst none insists on the syrnmet8rical arrangement.To establish more firmly the unsymmetrical constitution disul-phoxides each containing different aromatic groups have been synthesised by alternate methods. I n the first Eeries of experiments it seemed desirable to arrange that the aromatic groups K1 and R2 should differ by the nature of the substituents present and not merely by the position of these. The more stable of the known aromatic sulphur chlorides contain the nitrc-group and it was obvious to choose one of these as a component of one method of synthesis but the chief dificulty lay in obtaining a sulphur chloride of sufficient stability without this group for use in the alternate I 228 MILLER AND SMILES : process. This was overcome by the preparation of 2 5-dichloro-phenylsulphur chloride (X) from the corresponding disulphide and chlorine.From 2-nitrophenylsulphur chloride and silver 2 5-dichloro-benzenesulphinate a disulphoxide (XIa) of m. p. 142" was obtained, whilst from 2 5-dichlorobenzenesulphur chloride and silver 2-nitro-benzenesulphinate an isomeric compound (XIIa) melting at 129" was prepared. These substances differ not only in their physical properties but also in their chemical behaviour. When 2-nitro-phenyl 2 5-dichlorobenzenethiolsulphonate (XIa) is treated with 2-nitrophenyl mercaptan the dichlorobenzenesulphinic acid and o-nitrophenyl disdphide are formed (XI) whilst the action of the same mercaptan with 2 5-dichlorophenyl 2-nitrobenzenethiol-sulphonate (XIIa) yields o-nitrobenzenesulphinic acid and a mixture of the two possible disulphides (compare Smiles and Gibson Zoc.cit.). c1 \/ (XII.) c1 (X). The action of 2 5-dichlorophenyl mercaptan with the latter di-sulphoxide yielded (XII) the nitrosulphinic acid and the tetra-chloro-disulphide. Mild reduction of these disulphoxides gave analogous results ; these are collected on a subsequent page. A second series of experiments was made with material in which the groups R1 and R2 were closely similar for it was thought that such conditions would be favourable to intramolecular change-if indeed this were possible-of one thiolsulphonate to the other or of the thiolsulphonate to the true a-disulphoxide structure the latter change having been suggested by previous workers (Hinsberg Zoc.cit.; Fries Zoc. cit.). The materials chosen were the 2 5-dichloro-and 2 5-dibromo-phenyl derivatives. Thus 2 5-dichlorophenyl-sulphur chloride (X) and silver 2 5-dibromobenzenesulphinate furnished 2 5-dichlorophenyl 2 5-dibromobenzenethiolsulphonate (XIIIa) which melted at 119" even after being heated to 150" and cooled. On treatment with 2 5-dichlorophenyl mercaptan the tetra-chloro-disulphide and 2 5-dibromobenzenesulphinic acid were formed (XTTI) the structure indicated by synthesis being thus confirmed THE CONSTITUTION OF DISULPHOXIDES. PART 11. 223 The isomeric 2 5-dibromophenyl 2 5-dichlorobenzenethiol-sulphonate (XIVa) prepared in a similar manner melted a t 125" and with 2 5-dibromophenyl mercaptan yielded the tetrabromo-disulphide and 2 5-dichlorobcnzenesulphinic acid (XIV) .I n summarising the results of these experiments it is claimed that an unsymmetrical structure must be assigned to the disulph-oxides. Two unsymmetrical formulz have been advocated the thiolsulphonate and the anhydride arrangements (I1 and 111) ; there is ample reason for discarding the latter (Fries Zoc. cit.) whilst the former accords very closely with all the facts since discovered. E x P E R I M E N T A L. The disulphoxides were obtained those containing similar aromatic groups from the sulphinic acids by the usual method and those with dissimilar groups by the reaction of a silver sulphinate with the requisite sulphur chloride as follows. A solution of the sulphur halide in dry ether was shaken a t the ordinary t'emperature or boiled with an excess of the silver sulphinate until all the sulphur halide had disappeared the t8reatment being adapted to the reac-tivity of the materials and the stability of the sulphur halide used.Generally the disulphoxide separated as the reaction proceeded ; when this was complete the solid material was collected and the ciisulphoxide was extracted from it with a suitable solvent. In the majority of the cases studied the yields were good. The following substances were obtained by this method from the stated com-ponents. 2-Kit rophen yl 4-tolu e?zethiolsulphonate 02N*C6H4*S-S O,*C ,H,Me, from o-nitrophenylsulphur chloride and silver toluenesulphinate, formed colourless prisms m. p. 97" soluble in the usual organic solvents (Found S = 20-7 ; C = 50.0 ; H = 3.7.C1,HIIO,NS, requires S = 20.69; C = 50.55; H = 3.58 yo). The alcoholic solution of this substance became blue on addition of aqueous sodium hydroxide. 2-Xitrophenyl 4-chlorobenzenethioleulp~o?~ate, 0,EC ,H,.S.S Q2*C ,H,CI , from o-nitrophenylsulphur chloride and silver p-chlorobenzene-sulphinate formed colourless prisms m. p. 123" soluble in the usual organic media (Found S = 19-6; C1 = 10-5; C = 43.3; H = 2-66. Cl2H,O,NC1S2 requires S = 19-42 ; C1 = 10.74 ; C = 43.68 ; H = 2-44 Yo). 3-Xitrophenyl 2 5-dichiorobe?azenethiolsulphonate, 0,N*CsH4.S*S0,*CGH,Cl*, from o-nitrophenylsulphur chloride and silver 2 5-dichlorobenzene-sulphinate melted a t 142" and was sparingly soluble in commo 230 MILLER AND SMILES : solvents (Found C1= 19.4; S = 17.6.C1,H,04NCl,S requires C1 = 19.47; S = 17.61 yo). Like the foregoing disulphoxides, this substance gave a deep blue solution with alcoholic sodium hydroxide. 2 5-Dichlorophenyl 2-nitrobenzenethiolsulphonate, from silver o-nitrobenzenesulphinate and 2 5-dichlorophenyl-sulphur chloride separated from hot alcohol in colourless needles, m. p. 129" (Found S = 17:6; C1 = 19.6. C1,H,O,NC1,S requires S = 17.6 ; C1= 19.47 yo) ; aqueous sodium hydroxide added to the alcoholic solution did not give the characteristic blue colour. A mixture of the two isomeric substances in approximately equal amounts melted indefinitely between 88-95'. 2 5-Dichlorophenyl 2 5-dibromobenzenethioIsulphona.te, C6H,C1,*S*S0,*C &€,Br2, from 2 5-dichlorophenylsulphur chloride and silver 2 5-dibromo-benzenesulphinate separated from alcohol in colourless needles, m.p. 119' (Found S = 13.8; C1 + Br = 48.3. Cl,H60,C12Br,S, requires S = 13.45; C1+ Rr = 48-38 %). 2 5-Dibromophenyl 2 5-dichlorobenzenethiolsulphonate, C,H,Br,-S*S0,*C6H,C12, from silver 2 5-dichlorobenzenesulphinate and 2 5-dibromo-phenylsulphur bromide separated from hot alcohol in colourless prisms m. p. 125." This melting point remained unaltered after a sample had been fused and cooled. The substance is less soluble than the isomeric disulphoxide and a mixture of the two in approxi-mately equal amounts melted indefinitely at 110-114" (Found : S = 13.4; C1 + Br = 48.5. C12H60,C1,Br,S requires S = 13.45; C1 + Br = 48.38 yo). 2 5-Dichlorophenylsulphur chloride C6H,Cl,*SC1 was prepared by saturating a concentrated solution of the corresponding disulphide in dry carbon tetrachloride with chlorine.The residue obtained after the solvent had been evaporated was kept under diminished pressure when it solidified. The product was purified by crystallis-ation from ice-cold ether when the substance was obtained in golden-yellow needles m. p. 32-33' (Found C1 = 49.8; S = 14.9. C,H3Cl,S requires C1 = 49.8; S = 15.03 %). The substance was very soluble in organic media; dilute aqueous sodium hydroxide gave the corresponding disulphide and alkali sulphinate. The 2 5-dibromophenylsulphur bromide was obtained by a similar process as a yellow crystalline material but owing to its instability attempts to isolate it in a pure condition for analysis were un-successful some loss of bromine occurring with formation of the disulphide THE CONSTITUTION OF DISULPHOXIDES.PART 11. 231 Behaviour o j Disulphoxides with Methyl and Phenyl Magnesium Halides.-A dilute solution of the disulphoxide in ether was added to a cooled solution of the magnesium compound (1 mol.) in the Magnesium Sulphinic Other substances Disulphoside. derivative. acid yo. observed. D iphenyl Methyl 63 Ph*S.Me ; PhS.SPh. Diphenyl Phenyl 70 Ph*S.Ph ; PhS-SPh ; Ph-Ph. Di-p-tolyl Methyl S7 C,H,.S-Me; C,H,-S.SC,H,. Di-p-t olyl Pheiiyl 76 C,H,-S.Ph; (C,H,.S.)2 and Di-p-chlorophenyl Methyl 90 C6H,C1.S*&~e; (C6H,C1*S*)2. Ph *Ph . 2 5 2' 5'-Tetra- 7 9 82 4 4'-Dimethoxy- 7 7 68 MeO.C,H,.S.Me ; and disul-chlorodiphcnyl tolyl 3 S'-disul- phide.phoxide same solvent. The mixture was kept for 12 hours before treatment with water. Sufficient aqueous sodium thiosulphate was then added to remove free iodine if this were present and finally excess of dilute sulphuric acid. The sulphinic acid was extracted from the ethereal solution with dilute alkali the substances remaining being separately examined. A summary of the results is given in the foregoing table. The third column shows the approximate per-centages in which the sulphinic acids were isolated. These substances were identified by comparison with authentic samples and by con-version to the methylsulphones which were similarly compared. The latter have been previously described in literature with the exception of the following.4-Chlorophenylmethylsulphone C,H,Cl*SO,*CH, colourless needles, m. p. 96" was obtained by oxidation of the sulphide and by methylation of the sodium sulphinate with methyl sulphate (Found C1= 18.7; S = 16.6. C7H70,ClS requires C1= 18-58; 2 5-Dichlorophenylmethylsulp~one C6H,Cl,*S0,*CH, prepared in a similar manner separated from hot water in needles m. p. 88" (Found S = 14-0. C7H,02C12S requires S = 14-24 yo). The identification of sulphides was generally effected by oxidation to the sulphones. Action of Mercaptans with Disu1phoxides.-The method of opera-tion was similar to that already described (Smiles and Gibson Eoc. cit.) molecular proportions of the reagents being taken in alcohol. The results are collected in the following table ; the third and fourth columns respectively show the sulphinic acid and the disulphide which were isolated from the interaction of the stated disulphoxide and mercaptan.The yields of these products were generally of the order of 80% of theory and higher when the sparingly soluble S = 16.8 %) 232 THE CONSTITUTION OF DISULPHOXIDES. 2 2’-dinitrodiphenyl disulphide was dealt with. the h t column refer to numbered formulae. Disulphoxide. Mercaptan. 2-Nitrophenyl 2-Nitrophenyl 4-toluenethiol-sulphonate (VIII) 4-chloro benzene thiolsulphonate 2 5-dichloro-benzenethiol-sulphonate (XI) phenyl 2-nitro- phenyl benzenethiol-sulphonate phenyl 2-nitro-benzenethiol-sulphonate 2 5-Dichloro-phenyl 2 5-di- phenyl bromobenzene-thiolsulphonate phenyl 2 5-di- phenyl chlorobenzene-thiolsulphonate 2-Nitrophenyl 99 (1.W 2 -Nitrophenyl 9 9 2 5-Dichloro- 2 5-Dichloro-(=I) 2 5-Dichloro- 2-Nitrophenyl (=I) 2 5-Dichloro-(XIII) 2 5-Dibromo- 2 5-Dibromo-(XW) Sulphinic acid.4-Toluene-4-Chloro benzene-2 5-Dichloro-benzene-2 -Nitro benzene-2 6-Dibromo-benzene-2 5-Dichloro-benzene-PART 11. The numerals in Disulphide. Di-o-nitrophenyl 2 5 2’ 5’-Tetre-chlorodiphenyl A mixture not separated 2 5 2‘ 5’-Tetra-chlorodiphenyl 2 5 2’ B’-Tetra-bromodiphenyl Reduction of Disulphoxide+.-Three methods of reduction were employed. In casm 1 2 and 3 of the following table where com-plete reduction with hydrogen iodide was required the conditions devised by Hinsberg (Ber.1908 41 4295) were used. Milder reduction with this reagent was effected as follows. About 2 g. of the disulphoxide 3-4 C.C. of glacial acetic acid and a few C.C. of a saturated solution of sodium bisulphite containing ten drops of hydriodic acid (d 1.9) were constantly shaken with 50-100 C.C. of light petroleum for about 4 hour the necessary time varying some-what according to the disulphoxide taken. Then aqueous sodium carbonate was added until the whole was alkaline. I n cases where the dinitro-disulphide was formed this separated almost completely from the liquid. The solid material was collected the petroleum and the aqueous portion of the liquid being separately examined. The sulphinic acid was isolated from the aqueous portion and the di-sulphide from the solid or the petroleum.Examples of this type of reduction are given in Nos. 4,5,6 and 7 of the table. Reduction with sodium hyposulphite was conducted by shaking the disulph RESOLUTION OF CHLOROSULPHOACETIC ACID ETC. 233 oxide with a slight excess of a 3-4 yo aqueous solution of the reagent to which about l/lOth of its volume of alcohol had been added the mixture being kept alkaline by the addition of sodium carbonate. The disulphide formed was isolated by solution in ether whiIst the sulphinic acid and mercaptan were obtained from the aqueous portion. When mercaptan was present this was separated from the sulphinic acid as disulphide by treating the solution of sodium salts with a current of air. Examples are shown in h‘os.8 9 and 10 of the table. 1. 2. 3. 4. 5. 6. r S. 9. 10. Disulphoxide. 2-Nitrophenyl 4-toluencthiol-sulphonate 2-Nitrophenyl 4-chlorobenzene-thiolsulphonate 2 5-Dichlorophenyl 2-nitro-benzenethiolsulphonate 2-Nitrophenyl 4-toluenethiol-sulphonate 2-Nitrophenpl 4-chlorobenzene-tliiolsulphonate Di-4-chloroplienyl disulphoxide 2-Nitrophenyl 2 5-dichloro-bcnzenethiolsulphonate Di-p-tolyl disulphoxide 2 5-Dichlorophenyl 2-nitro-benzenethiolsulphonatc 2-Nitrophenyl 2 5-dichloro-beiizenethiolsulphcnate Products isolated. 2 2’-Dinitrodiphenyl disulphide 2 2’-Dinitrodiphenyl disulphide and 4 4’-dichlorodiphenyl disulphide A mixture of disulphides; not separated 4-Toluenesulphinic acid and 2 2’-di-nitrodiphenyl disulphide 4-Chlorobenzenesulphinic acid and 2 2’-dinitrodiphenyl disulphide 4-Chlorobenzenesulphinic acid and 4 4’-clichlorodiphenyl disulphide 2 5-Dichlorobenzenesulphinic acid and 2 2’-dinitrodip~ienyl clisul-phide p-Toluenesulphinic acid and p-tolyl mercaptan 2-Nitrobenzenesulphinic acid and 2 5 2‘ 5’-tetrachlorodiphenyl cli-sulphidc 2 5-Dichlorobenzenesulphinic acid, 2-nitrothiophenol and the disul-phide I n conclusion we desire to thank the Department of Scientific and Industrial Research for a grant which has enabled one of us to take part in this work.Our thanks are also due to Mr. W. E. Wright for the derivatives of 2 5-dibromophenyl mercaptan used in these experiments. KING’S COLLEGE LONDO?;. [Received November 1 lth 1924.224 MILLER AND SMILES : XXXVII1.-The Constitution of Disulphoxides. Part I I . By CECIL JAMES MILLER and SAMUEL SMILES. ALTHOUGH the symmetrical structure of the disulphoxides (I) has been generally accepted the evidence adduced in its favour has been incorrectly interpreted and is in fact ambiguous and many simple reactions of these substances appear clearly to indicate the thio-sulphonate structure (IT) such for example as their behaviour with zinc dust potassium sulphide sodium arsenite and mer-captans (J. 1924 125 176). Moreover this view is supported by syntheses of disulphoxides from sulphenic halides and silver sul-phinates (Zincke Annalen 1912 391 67). Since all the definite evidence thus favoured the thiosulphonate structure it was concluded that this should not be abandoned but instead should be regarded as the most probable until final proof of one structure or another was forthcoming.(I.) Ar*E*fi*Ar Ar*so,*s*Ar ArR*O*SAr (111. ) 00 (11.1 0 The experiments now described provide the necessary further proof of this unsymmetrical constitution in that (1) the action of Grignard’s reagent with the disulphoxides must be added to those already quoted as indicating this structure (2) the reduction of disulphoxides with hydrogen iodide which hitherto has been quoted as the main evidence for the symmetrical formula is not only use-less as such but accords with the thiosulphonate structure (3) the unsymmetrical character of the disulphoxides is demonstrated by synthesis. slthough the behaviour of numerous carbon compounds of sulphur with alkyl and aryl magnesium halides has been investi-gated (Lapworth J .1912 101 297; Hepworth and Clapham J., 1921 119 IlSS; Wedekind Rer. 1921 54 16041 that of the disulphoxides appears to have escaped attention. These substances are very readily attacked by the magiiesinm compounds and usin THE CONSTITUTION OF DISULPHOXIDES. PART 11. 225 equimolecular proportions of the reactants high yields of the sulphinic acids have been isolated fission of the disulphoxide taking place apparently according to the following scheme (IV) : The sulphinic acid was obtained in every case examined but the fate of the thioaryl group of the disulphoxide varied according to the nature of the magnesium compound used with magnesium inethyl iodide the methyl aryl sulphide Ar*S*CH, was commonly obtained whilst with magnesium phenyl iodide the disulphide and diphenyl also were observed.The chief point at issue is tlhe situation of the oxygen in the molecule of the disulphoxide and with the symmetrical formula it is very difficult to explain the isolation of SOY; of this as sulphinic acid. According to this symmetrical constitution it would be expected that fission of the molecule would result in the formation of a sulphoxide (V) but this has not been observed. The results of this decomposition evidently support the unsymmetrical structure and appear inexplicable on the basis of the symmetrical formula. The mode of experiment is described and the results are tabulated on subsequent pages.The fact that the disulphoxides are easily reduced by hydrogen iodide t o disulphides has been regarded as sufficient reason for rejecting the thiosulphonate structure and as proving the presence of the true disulphoxide arrangement (Hinsberg Ber. 1908 41, 2836 4294; 1909 42 1278; Fries Ber. 1914 47 1195). It is assumed that the reduction is direct and since the sulphonyl group usually is not easily reduced by this reagent whilst the thionyl group is readily attacked the conclusion would seem justified but it has been pointed out (Smiles and Gibson J. 1924 125 176) that the force of the argument depends on the assumption that reduction is direct and is not accompanied by fission of the mole-cule. If however rupture does take place the reduction cannot be used as an argument against the unsymmetrical or in favour of the symmetrical formula for in either case a disulphide must be expected as the final product of the reaction.The question whether this fission takes place or not may be answered by the reduction of a disulphoxide containing different aromatic groups. I n such a case, if the unsymmetrical disulphide is the sole product (VI) the assumption of direct reduction is clearly justified but if both or even one of the symmetrical disulphides are obtlained (VII) it must be admitted that rupture of the dithio-system has taken place. (vI.) R1*SO*SO*R2 -+ R1*S-S*R2 (VII.) 2R1*S,0,*R2 -+ (RlS) + (R2S), VOL. CXXVII. 226 MILLER AND SMILES: Disulphoxides containing merent aromatic nuclei are readily prepared by an extension of the synthetical method of Zincke (Zoc.cit.) For example when the silver salts of p-toluenesulphinic acid and p-chlorobenzenesulphinic acid are treated with o-nitrophenyl-sulphur chloride the o-nitrophenyl p-toluenethiolsulp~ona.te (VIII) and o-nitrophenyl p-chlorobenzenethiolsulphonate (IX) are respec-tively 'formed. N02*C,H4*SCI + AgSO,*C,H = AgCl + NO,*C,H,*S*SO,*C,H,. (VIII.) Reduction of these substances with hydrogen iodide in the usual manner (compare Hinsberg Zoc. cit.) furnished o-nitrophenyl di-sulphide (N02*C,H,*S*), in good yield and in the case of the chloro-derivative p-chlorophenyl disulphide also was isolated. Hence it is clear that the disulphoxide system has. been broken during the process of reduction and the reaction cannot be admitted as evidence favouring the symmetrical and excluding the unsymmetrical structure.Nothing else can be deduced from this result but further information has been gained by adopting milder conditions of reduction with hydrogen iodide or by the use of dilute hyposulphite (in presence of sodium carbonate). The derivative (VIII) then yielded p-toluenesulphinic acid and the nitrophenyl disulphide the chloronitro-derivative (IX) gave p-chlorobenzenesulphinic acid and the nitro-disulphide whilst p-tolyl disulphoxide and p-chlorophenyl disulphoxide gave the corresponding sulphinic acids and disulphides or mercaptans. These results are similar to those obtained by Gutmann (Ber. 1914 47 635) on reduction with sodium arsenite. In the cases of disulphoxides containing similar aromatic groups this result does not enable a decision to be made in favour of either structure for both permit the formation of a sulphinic acid by hydrolytic fission, R*SO-SO*R + R*SO,H + R*S*OH + R*SO,*SR whilst the disulphide would result from reduction of the less stable sulphenic acids.Turning to the case of a disulphoxide containing different aromatic groups a distinction between the requirements of either structure is found. On the basis of the symmetrical arrangement the formation of two sulphinic acids may be expected, for there is no reason to suppose that hydrolysis will take place in one direction only when R1 and R2 are of similar character : RlS*OH + R2*S0,H +- R1*SO*SO*R2 -+ R1*S02H + R2*S*OH THE CONSTITUTION OF DISULPHOXIDES.PART 11. 227 On the other hand according to the thiosulphonate structure only one sulphinic acid should be formed : 2R1*S0,*S=R2 + 2R1*S0,H + (SR2)2 The latter condition accords with the result obtained by the reduction of these substances only one sulphinic acid has been isolated in each case examined. Moreover it is significant that the sulphinic acid-isolated was always the one which had been used as ifi component in the synthesis thus nitrophenyl t'oluenethiolsulphonate (VIII) yielded p-toluenesulphinic acid and o-nitrophenyl disulphide, and nitrophenyl chlorobenzenethiolsulphonate (IX) gave p-chloro-benzenesulphinic acid and the nitro-disulphide : 2CsH,C1*S0,*S*C6H4*No2 + 2C6H,C1*S02H + (NO,*C,I~,*S.),. The action of mercaptans with these disulphoxides is closely analo-gous (compare Smiles and Gibson loc.cit.). o-Nitrophenyl mercaptan yields in both cases the o-nitrophenyl disulphide and the corre-ponding sulphinic acid : CiH,.SO,* S-CGH,*NO, H S*CGH,-N02 The information gained from this extended study of the reduction of the disulphoxides therefore clearly favours the unsymmetrical structure. Taking a general review of the characteristic reactions of the disulphoxides it is seen that all yield the sulphinic acid and a product which contains the thioaryl group; these substances result from the action of zinc dust magnesium alkyl halides potass-ium sulphide mercaptans and of arsenite and other mild reducing agents. The majority of these reactions indicate an unsymmetrical structure a few are ambiguous in their import whilst none insists on the syrnmet8rical arrangement.To establish more firmly the unsymmetrical constitution disul-phoxides each containing different aromatic groups have been synthesised by alternate methods. I n the first Eeries of experiments it seemed desirable to arrange that the aromatic groups K1 and R2 should differ by the nature of the substituents present and not merely by the position of these. The more stable of the known aromatic sulphur chlorides contain the nitrc-group and it was obvious to choose one of these as a component of one method of synthesis but the chief dificulty lay in obtaining a sulphur chloride of sufficient stability without this group for use in the alternate I 228 MILLER AND SMILES : process. This was overcome by the preparation of 2 5-dichloro-phenylsulphur chloride (X) from the corresponding disulphide and chlorine.From 2-nitrophenylsulphur chloride and silver 2 5-dichloro-benzenesulphinate a disulphoxide (XIa) of m. p. 142" was obtained, whilst from 2 5-dichlorobenzenesulphur chloride and silver 2-nitro-benzenesulphinate an isomeric compound (XIIa) melting at 129" was prepared. These substances differ not only in their physical properties but also in their chemical behaviour. When 2-nitro-phenyl 2 5-dichlorobenzenethiolsulphonate (XIa) is treated with 2-nitrophenyl mercaptan the dichlorobenzenesulphinic acid and o-nitrophenyl disdphide are formed (XI) whilst the action of the same mercaptan with 2 5-dichlorophenyl 2-nitrobenzenethiol-sulphonate (XIIa) yields o-nitrobenzenesulphinic acid and a mixture of the two possible disulphides (compare Smiles and Gibson Zoc.cit.). c1 \/ (XII.) c1 (X). The action of 2 5-dichlorophenyl mercaptan with the latter di-sulphoxide yielded (XII) the nitrosulphinic acid and the tetra-chloro-disulphide. Mild reduction of these disulphoxides gave analogous results ; these are collected on a subsequent page. A second series of experiments was made with material in which the groups R1 and R2 were closely similar for it was thought that such conditions would be favourable to intramolecular change-if indeed this were possible-of one thiolsulphonate to the other or of the thiolsulphonate to the true a-disulphoxide structure the latter change having been suggested by previous workers (Hinsberg Zoc.cit.; Fries Zoc. cit.). The materials chosen were the 2 5-dichloro-and 2 5-dibromo-phenyl derivatives. Thus 2 5-dichlorophenyl-sulphur chloride (X) and silver 2 5-dibromobenzenesulphinate furnished 2 5-dichlorophenyl 2 5-dibromobenzenethiolsulphonate (XIIIa) which melted at 119" even after being heated to 150" and cooled. On treatment with 2 5-dichlorophenyl mercaptan the tetra-chloro-disulphide and 2 5-dibromobenzenesulphinic acid were formed (XTTI) the structure indicated by synthesis being thus confirmed THE CONSTITUTION OF DISULPHOXIDES. PART 11. 223 The isomeric 2 5-dibromophenyl 2 5-dichlorobenzenethiol-sulphonate (XIVa) prepared in a similar manner melted a t 125" and with 2 5-dibromophenyl mercaptan yielded the tetrabromo-disulphide and 2 5-dichlorobcnzenesulphinic acid (XIV) .I n summarising the results of these experiments it is claimed that an unsymmetrical structure must be assigned to the disulph-oxides. Two unsymmetrical formulz have been advocated the thiolsulphonate and the anhydride arrangements (I1 and 111) ; there is ample reason for discarding the latter (Fries Zoc. cit.) whilst the former accords very closely with all the facts since discovered. E x P E R I M E N T A L. The disulphoxides were obtained those containing similar aromatic groups from the sulphinic acids by the usual method and those with dissimilar groups by the reaction of a silver sulphinate with the requisite sulphur chloride as follows. A solution of the sulphur halide in dry ether was shaken a t the ordinary t'emperature or boiled with an excess of the silver sulphinate until all the sulphur halide had disappeared the t8reatment being adapted to the reac-tivity of the materials and the stability of the sulphur halide used.Generally the disulphoxide separated as the reaction proceeded ; when this was complete the solid material was collected and the ciisulphoxide was extracted from it with a suitable solvent. In the majority of the cases studied the yields were good. The following substances were obtained by this method from the stated com-ponents. 2-Kit rophen yl 4-tolu e?zethiolsulphonate 02N*C6H4*S-S O,*C ,H,Me, from o-nitrophenylsulphur chloride and silver toluenesulphinate, formed colourless prisms m. p. 97" soluble in the usual organic solvents (Found S = 20-7 ; C = 50.0 ; H = 3.7.C1,HIIO,NS, requires S = 20.69; C = 50.55; H = 3.58 yo). The alcoholic solution of this substance became blue on addition of aqueous sodium hydroxide. 2-Xitrophenyl 4-chlorobenzenethioleulp~o?~ate, 0,EC ,H,.S.S Q2*C ,H,CI , from o-nitrophenylsulphur chloride and silver p-chlorobenzene-sulphinate formed colourless prisms m. p. 123" soluble in the usual organic media (Found S = 19-6; C1 = 10-5; C = 43.3; H = 2-66. Cl2H,O,NC1S2 requires S = 19-42 ; C1 = 10.74 ; C = 43.68 ; H = 2-44 Yo). 3-Xitrophenyl 2 5-dichiorobe?azenethiolsulphonate, 0,N*CsH4.S*S0,*CGH,Cl*, from o-nitrophenylsulphur chloride and silver 2 5-dichlorobenzene-sulphinate melted a t 142" and was sparingly soluble in commo 230 MILLER AND SMILES : solvents (Found C1= 19.4; S = 17.6.C1,H,04NCl,S requires C1 = 19.47; S = 17.61 yo). Like the foregoing disulphoxides, this substance gave a deep blue solution with alcoholic sodium hydroxide. 2 5-Dichlorophenyl 2-nitrobenzenethiolsulphonate, from silver o-nitrobenzenesulphinate and 2 5-dichlorophenyl-sulphur chloride separated from hot alcohol in colourless needles, m. p. 129" (Found S = 17:6; C1 = 19.6. C1,H,O,NC1,S requires S = 17.6 ; C1= 19.47 yo) ; aqueous sodium hydroxide added to the alcoholic solution did not give the characteristic blue colour. A mixture of the two isomeric substances in approximately equal amounts melted indefinitely between 88-95'. 2 5-Dichlorophenyl 2 5-dibromobenzenethioIsulphona.te, C6H,C1,*S*S0,*C &€,Br2, from 2 5-dichlorophenylsulphur chloride and silver 2 5-dibromo-benzenesulphinate separated from alcohol in colourless needles, m.p. 119' (Found S = 13.8; C1 + Br = 48.3. Cl,H60,C12Br,S, requires S = 13.45; C1+ Rr = 48-38 %). 2 5-Dibromophenyl 2 5-dichlorobenzenethiolsulphonate, C,H,Br,-S*S0,*C6H,C12, from silver 2 5-dichlorobenzenesulphinate and 2 5-dibromo-phenylsulphur bromide separated from hot alcohol in colourless prisms m. p. 125." This melting point remained unaltered after a sample had been fused and cooled. The substance is less soluble than the isomeric disulphoxide and a mixture of the two in approxi-mately equal amounts melted indefinitely at 110-114" (Found : S = 13.4; C1 + Br = 48.5. C12H60,C1,Br,S requires S = 13.45; C1 + Br = 48.38 yo).2 5-Dichlorophenylsulphur chloride C6H,Cl,*SC1 was prepared by saturating a concentrated solution of the corresponding disulphide in dry carbon tetrachloride with chlorine. The residue obtained after the solvent had been evaporated was kept under diminished pressure when it solidified. The product was purified by crystallis-ation from ice-cold ether when the substance was obtained in golden-yellow needles m. p. 32-33' (Found C1 = 49.8; S = 14.9. C,H3Cl,S requires C1 = 49.8; S = 15.03 %). The substance was very soluble in organic media; dilute aqueous sodium hydroxide gave the corresponding disulphide and alkali sulphinate. The 2 5-dibromophenylsulphur bromide was obtained by a similar process as a yellow crystalline material but owing to its instability attempts to isolate it in a pure condition for analysis were un-successful some loss of bromine occurring with formation of the disulphide THE CONSTITUTION OF DISULPHOXIDES.PART 11. 231 Behaviour o j Disulphoxides with Methyl and Phenyl Magnesium Halides.-A dilute solution of the disulphoxide in ether was added to a cooled solution of the magnesium compound (1 mol.) in the Magnesium Sulphinic Other substances Disulphoside. derivative. acid yo. observed. D iphenyl Methyl 63 Ph*S.Me ; PhS.SPh. Diphenyl Phenyl 70 Ph*S.Ph ; PhS-SPh ; Ph-Ph. Di-p-tolyl Methyl S7 C,H,.S-Me; C,H,-S.SC,H,. Di-p-t olyl Pheiiyl 76 C,H,-S.Ph; (C,H,.S.)2 and Di-p-chlorophenyl Methyl 90 C6H,C1.S*&~e; (C6H,C1*S*)2. Ph *Ph . 2 5 2' 5'-Tetra- 7 9 82 4 4'-Dimethoxy- 7 7 68 MeO.C,H,.S.Me ; and disul-chlorodiphcnyl tolyl 3 S'-disul- phide.phoxide same solvent. The mixture was kept for 12 hours before treatment with water. Sufficient aqueous sodium thiosulphate was then added to remove free iodine if this were present and finally excess of dilute sulphuric acid. The sulphinic acid was extracted from the ethereal solution with dilute alkali the substances remaining being separately examined. A summary of the results is given in the foregoing table. The third column shows the approximate per-centages in which the sulphinic acids were isolated. These substances were identified by comparison with authentic samples and by con-version to the methylsulphones which were similarly compared. The latter have been previously described in literature with the exception of the following.4-Chlorophenylmethylsulphone C,H,Cl*SO,*CH, colourless needles, m. p. 96" was obtained by oxidation of the sulphide and by methylation of the sodium sulphinate with methyl sulphate (Found C1= 18.7; S = 16.6. C7H70,ClS requires C1= 18-58; 2 5-Dichlorophenylmethylsulp~one C6H,Cl,*S0,*CH, prepared in a similar manner separated from hot water in needles m. p. 88" (Found S = 14-0. C7H,02C12S requires S = 14-24 yo). The identification of sulphides was generally effected by oxidation to the sulphones. Action of Mercaptans with Disu1phoxides.-The method of opera-tion was similar to that already described (Smiles and Gibson Eoc. cit.) molecular proportions of the reagents being taken in alcohol. The results are collected in the following table ; the third and fourth columns respectively show the sulphinic acid and the disulphide which were isolated from the interaction of the stated disulphoxide and mercaptan.The yields of these products were generally of the order of 80% of theory and higher when the sparingly soluble S = 16.8 %) 232 THE CONSTITUTION OF DISULPHOXIDES. 2 2’-dinitrodiphenyl disulphide was dealt with. the h t column refer to numbered formulae. Disulphoxide. Mercaptan. 2-Nitrophenyl 2-Nitrophenyl 4-toluenethiol-sulphonate (VIII) 4-chloro benzene thiolsulphonate 2 5-dichloro-benzenethiol-sulphonate (XI) phenyl 2-nitro- phenyl benzenethiol-sulphonate phenyl 2-nitro-benzenethiol-sulphonate 2 5-Dichloro-phenyl 2 5-di- phenyl bromobenzene-thiolsulphonate phenyl 2 5-di- phenyl chlorobenzene-thiolsulphonate 2-Nitrophenyl 99 (1.W 2 -Nitrophenyl 9 9 2 5-Dichloro- 2 5-Dichloro-(=I) 2 5-Dichloro- 2-Nitrophenyl (=I) 2 5-Dichloro-(XIII) 2 5-Dibromo- 2 5-Dibromo-(XW) Sulphinic acid.4-Toluene-4-Chloro benzene-2 5-Dichloro-benzene-2 -Nitro benzene-2 6-Dibromo-benzene-2 5-Dichloro-benzene-PART 11. The numerals in Disulphide. Di-o-nitrophenyl 2 5 2’ 5’-Tetre-chlorodiphenyl A mixture not separated 2 5 2‘ 5’-Tetra-chlorodiphenyl 2 5 2’ B’-Tetra-bromodiphenyl Reduction of Disulphoxide+.-Three methods of reduction were employed. In casm 1 2 and 3 of the following table where com-plete reduction with hydrogen iodide was required the conditions devised by Hinsberg (Ber.1908 41 4295) were used. Milder reduction with this reagent was effected as follows. About 2 g. of the disulphoxide 3-4 C.C. of glacial acetic acid and a few C.C. of a saturated solution of sodium bisulphite containing ten drops of hydriodic acid (d 1.9) were constantly shaken with 50-100 C.C. of light petroleum for about 4 hour the necessary time varying some-what according to the disulphoxide taken. Then aqueous sodium carbonate was added until the whole was alkaline. I n cases where the dinitro-disulphide was formed this separated almost completely from the liquid. The solid material was collected the petroleum and the aqueous portion of the liquid being separately examined. The sulphinic acid was isolated from the aqueous portion and the di-sulphide from the solid or the petroleum.Examples of this type of reduction are given in Nos. 4,5,6 and 7 of the table. Reduction with sodium hyposulphite was conducted by shaking the disulph RESOLUTION OF CHLOROSULPHOACETIC ACID ETC. 233 oxide with a slight excess of a 3-4 yo aqueous solution of the reagent to which about l/lOth of its volume of alcohol had been added the mixture being kept alkaline by the addition of sodium carbonate. The disulphide formed was isolated by solution in ether whiIst the sulphinic acid and mercaptan were obtained from the aqueous portion. When mercaptan was present this was separated from the sulphinic acid as disulphide by treating the solution of sodium salts with a current of air.Examples are shown in h‘os. 8 9 and 10 of the table. 1. 2. 3. 4. 5. 6. r S. 9. 10. Disulphoxide. 2-Nitrophenyl 4-toluencthiol-sulphonate 2-Nitrophenyl 4-chlorobenzene-thiolsulphonate 2 5-Dichlorophenyl 2-nitro-benzenethiolsulphonate 2-Nitrophenyl 4-toluenethiol-sulphonate 2-Nitrophenpl 4-chlorobenzene-tliiolsulphonate Di-4-chloroplienyl disulphoxide 2-Nitrophenyl 2 5-dichloro-bcnzenethiolsulphonate Di-p-tolyl disulphoxide 2 5-Dichlorophenyl 2-nitro-benzenethiolsulphonatc 2-Nitrophenyl 2 5-dichloro-beiizenethiolsulphcnate Products isolated. 2 2’-Dinitrodiphenyl disulphide 2 2’-Dinitrodiphenyl disulphide and 4 4’-dichlorodiphenyl disulphide A mixture of disulphides; not separated 4-Toluenesulphinic acid and 2 2’-di-nitrodiphenyl disulphide 4-Chlorobenzenesulphinic acid and 2 2’-dinitrodiphenyl disulphide 4-Chlorobenzenesulphinic acid and 4 4’-clichlorodiphenyl disulphide 2 5-Dichlorobenzenesulphinic acid and 2 2’-dinitrodip~ienyl clisul-phide p-Toluenesulphinic acid and p-tolyl mercaptan 2-Nitrobenzenesulphinic acid and 2 5 2‘ 5’-tetrachlorodiphenyl cli-sulphidc 2 5-Dichlorobenzenesulphinic acid, 2-nitrothiophenol and the disul-phide I n conclusion we desire to thank the Department of Scientific and Industrial Research for a grant which has enabled one of us to take part in this work. Our thanks are also due to Mr. W. E. Wright for the derivatives of 2 5-dibromophenyl mercaptan used in these experiments. KING’S COLLEGE LONDO?;. [Received November 1 lth 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700224

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

RESOLUTION OF CHLOROSULPHOACETIC ACID ETC. 233 XXXIX.-Resolution of Chlorosulphoacetic Acid into its Optically Active Components. By HILMAR JOHANNES BACKER and WILHELM GERARD BURGERS. CHLOROSULPHOACETIC acid SO,EI*CHCl*CO,H one of the simplest compounds with an asymmetric carbon atom has hitherto resisted all attempts at optical resolution. Porcher stated (Bull. SOC. cJzi?n. 1902 [iii] 27 438) that resolution is possible but Pope and T 234 BACKER AND BURGERS RESOLUTION OF CHLOROSULPHOACETIC Read repeating his experiments did not confirm his results and were led " to dismiss them as not in accordance with experiment " (J. 1908 93 794; 1914 105 811). We have resolved the racemic acid by a method which apparently had not previously been applied to such purposes namely by slow crystallisation of alkaloidal salts in the cold.After a preliminary examination of their solubility the alkaloid salts of chlorosulphoacetic acid were prepared by treating the sodium salt at room temperature with a soluble salt of the alkaloid in such dilutioii that crystallisation of the product did not start at once and only a small part was subsequently deposited. Since the solubility of the alkaloid salts was so small that the effect of the active chlorosulphoacetic acid on the rotation was inappreciable the sodium and ammonium salts were examined. For purification the same " cold crystallisation " was used. The alkaloid salt was therefore converted a t 0" into the ammonium salt by means of the theoretical quantity of dilute ammonia the alkaloid was filtered off and the solution of the ammonium salt was mixed with the alkaloid (as acetate) in such concentration that again only a part of the alkaloid salt crystallised.By means of yohimbine a dextrorotatory ammonium salt was obtained and an acid of nearly twice the rotation. I-Sjtrychnine gave fhe dextro-rotatory acid whilst d-cinchonine furnished the laevo-component, so that the small rotation we first obtained could not be ascribed to the presence of traces of the alkaloids. The highest constant value of the molecular rotation was for the acid [MI = & 39" and for the neutral ammonium salt [MI = & 20". The acids and their salts gradually racemise in solution a t room temperature. Bases accelerate racemisation of the salts. On evaporation the solutions lose their activity completely.These active acids therefore are more stable than fluorochlorobromo-acetic acid which shows activity only in its alkaloidal salts (Swarts, Bull. roy. Be@. 1896 [iii] 31 25) but they do not attain the high stability of chloroiodomethanesulphonic acid which is not racemised by any of the usual methods (Pope and Read loc. cit.).* E X P E R I M E N T A L . Preparation of Chlorosulphoacetic Acid .-The method used for the preparation of other sulphocarboxylic acids (Rec. trav. chim. , 1920 39 694; 1924 43 297) gives a good yield and a pure product. * This research is being continued and the method will be applied to other resolutions. The present results are published because of the departure of Mr. Burgers.-H. J. B ACID INTO ITS OPTICALLY ACTIVE COXPONENTS .235 To 94 g. (1 mol.) of freshly distilled chloroacetic acid cooled with ice are gradually added SO g. (1 mol.) of sulphur trioxide with constant shaking. A viscous nearly colourless syrup of the mixed anhydride of sulphuric and chloroacetic acids is formed (Found by titration after decomposition with water equiv. = 57. CH,Cl*CO*O*SO,H decomposed by water into CH,Cl*CO,H + H,SO,, requires a mean equivalent weight of 174.513 = 58.2). The anhydride is converted into the sulphonic acid by warming: CH,C1*C0*O*SO3H -+ SO,H*CHCl*CO,H. At 70" the external heating is discontinued; the heat of reaction causes the tem-perature to rise to about 140" the liquid becoming coloured towards 100" and a feeble evolution of gas (CO and SO,) setting in.The product is a brown syrup consisting mainly of chlorosulphoacetic acid (Found equiv. = 84. Calc. equiv. = 174.32 = 87.2). When kept over-night the acid may crystallise. A solutim of the syrup or crystallised mass in 5 litres of water is t'reated with barium carbonate in excess (200 g.). The filtrate, evaporated to 250 C.C. and cooled deposits 270 g. of pure crystalline barium chlorosulphoacetate (yield more than 80%) (Found : Ea = 41.83 41.84. On concentration the mother-liquor gives as in Andreasch's preparation (Monatsh., 1 SS6 7 158) crystals of barium chloromethanedisulphonate (about 1.5 g.) (Found H20 = 17-37; Ba = 32.56 32.54. Calc. for CIE0,ClS,Ba,4H20 H,O = 17.24; Ba = 32.860/). Chlorosulphoacetic acid was prepared by shaking its barium salt rrzechanically for 1 hour with the calculated quantity of 2AT-sulphuric acid.The filtrate which was free from sulphuric acid and barium was concentrated fist by distillation under reduced pressure then in a desiccator over sulphuric acid and finally over phosphorus pentoxide until crystallisation set in. Chlorosulphoacetic acid forms very hygroscopic crystals containing 1H,O (Found Jl = 191.8. Calc. for C,H,05C1S,H,0 X = 192-56). The melting point determined in an apparatus for hygroscqpic substances (Chem. TYeelcblad 1919 16 1564) was 83". Sormal Alkaloidal Xalts .-The normal salts of chlorosulpho-acetic acid with various alkaloids were prepared either by dissolving the bases in the equivalent quantity of the acid or by double decomposition from sodium chlorosulphoacetate with a soluble salt, usually the acetate or phosphate of the alkaloid.The salts all of which were obtained in the crystalline state,* were titrated with sodium hydroxide in presence of phenolphthalein or thyrnol-p ht halein. Calc. Ba = 41.89y0). * Pope and Read state that the quinine and cinchonine salts were not obtained crystalline. Their strychnine salt contained 1H,O. I" 236 BACKER AND BURGERS RESOLUTION OF CRLOROSULPHOACETIC The normal quinine salt forms a felted mass of small needles containing 4H20 (Found H20 = 8-03 M = 894. requires H20 = 8.05%; M = 895.0). The normal cinchonine salt crystallises with 1H20 in silky needles, concentrically arranged in dense globules (Found H20 = 2.36; M = 780. C2H,0SClS,2C1,H220N2,H20 requires H20 = 2.31% ; M = 780.9).The normal strychnine salt when crystallised from a dilute solution forms needles about & inch long containing 3H20 (Found H20 = 6.08 6.15; M = 896.7 897-2 895.8. C2H,06C1S,2C~,02N2,4H,0 requires H,O = 6.03%; M = 897). d-Chlorosulphoacetic Acid.-Sodium chlorosulphoacetate (0.05 mol.) in 1150 C.C. of water was treated with 33.4 g. (0.1 mol.) of strychnine dissolved in the same volume of water containing 11 g. of acetic acid. Slender needles began to separate within 1 hour and after 10 hours a t 20° 9 g. of strychnine salt were collected corresponding to 20% of the quantity formed (44-8 g.). For polarimetric examination weighed quantities of the strych-nine salt (06-2 g.) were shaken a t 0" with the theoretical quantity of dilute ammonia the volume was brought to 20 c.c.and the solution of the ammonium salt after being extracted four times with half its volume of chloroform was examined by means of a polarimeter (Schmidt and Haensch) with monochromator. In some cases the concentration of the ammonium salt was verified by evaporation of the solution. The rotatory power was measured for X = 589 pp (D) and for two arbitrary wave-lengths in the green (A = 533 pp) and blue (A = 494 pp). The ammonium salt pre-pared from the strychnine salt mentioned above gave the following figures Concentration 0.00480 g.-mol. in 100 c.c.; Z = 2; aD = + 0.18"; [MI = + 18.7". For recrystallisation 4-48 g. (0.005 mol.) of the active strychnine salt were decomposed by ammonia.The separated strychnine was dissolved in dilute acetic acid and added to the solution of the ammonium salt. The total volume being 230 c.c. the concentra-tion was the same as above. 1.3 Grams or nearly 30% separated. Rotation of the ammonium salt Conc. 0.01115 g.-mol. in 100 C.C. ; 1 = 2 ; tcD = + 0*45" as33 = + 0*58" aqD4 = + 0.74" ; [MID = + 20.2" = + 26-0" [MI,, = + 33.2". Conc. 0.00560 g.-mol. in 100 c.c.; I = 2; C C ~ = + 0-23" a533 = + 0*30" a4D4 = + 0.37"; [MID = + 20.5" [M],, = + 26-8" [M'J,, = $- 33.0". Addition of sulphuric acid to liberate the acid (2 mols. for 1 mol. of ammonium salt) increased the rotatory power but this did not chang ACID IKTO ITS OPTICALLY ACTIVE COMPONENTS. 237 further on addition of more sulphuric acid. Rotation of the free acid : C'OnC.0.005 g.-mol. in 100 C.C. ; ,! = 2 ; a = + o.40°,a533 = + o.5?o, 1 - Chlorosulphoacetic Acid .-Sodium c hlorosulp hoac et a t e (0 -0 5 mol.) was mixed with 30 g. (0.1 mol.) of cinchonine dissolved in water containing 9 g . of acetic acid. The total volume was 1150 C.C. After 2 days 5-5 g. of the cinchonine salt or 14% of the total amount (39 g.) had separated. The product was decomposed with ammonia like the strychnine salt the only differeme being that the alkaloid was filtered off before extraction of the solution with chloroform. Rotation of the ammonium salt Conc. 0.00278 g.-mol. in 100 c.c.; I = 2 : The active cinchonine salt (3.9 g.; 0.005 mol.) was recrystallised in the same way as the strychnine salt. From 115 c.c. the same concentration as above there separated 0.95 g.or 257;. Rotatory power of the ammonium salt Conc. 0.00324 g.-mol. in 100 c.c.; I = 2 ; aD = - 0.12" = - 0*17" agg4 = - 0.23"; [AM] = The acid liberated by an excess of sulphuric acid gave the figures : Conc. 0.00305 g.-mol. in 100 c.c.; mD = - 0.23" c1333 = - 0*29", c1494 = -/- 0.62"; [Jf] = + 40" [A$f]533 = + 52" [l!f]gg4 = $- 62". aD = - 0.08" ; f i t l ] D == - 14.4". - 18*5" [ill]533 == - 26.2") [Jf],g4 = - 35.5". aqg4 = - 0.38" ; pi], = - 37-70 [ J ~ I ~ ~ ~ = - 47.50 [N],g = - 62-30. Thus the mean values for the rotatory power are : Chlorosulphoacetic acid [MI = zfr 39" = & 50", h'eutral ammonium salt [il.i'] = & 20" = 36", [MI494 = Zt 62". [&!]494 = & 34". Xacenzisntioiz. The rotation of a neutral solution of the d-ammonium salt contain-ing 0.1 mol.per litre had fallen in a fortnight to half its value. The rotation of a solution containing 0.05 11101. of the d-acid per litre and an excess of sulphuric acid diminished in 10 days by one-fourth. A solution of 0.05 mol. of the ammonium salt per litre containing 0.1 mol. of free ammonia had lost one-third of its rotatory power within 24 hours. The d-acid and the d-ammonium salt each in a solution containing 0.05 mol. per litre were rapidly heated boiled for 1 minute and immediately cooled. Their rotatory powers had decreased by about 5%. The same solutions evaporated on a water-bath and diluted to the original volume racemised completely. Examined a week later it m-as inactive. ORGANIC CHEMICAL LABORATORY, (HOLLAXD ).UNIVERSITY OF GRONINGEN [Received September 8th. 1924. RESOLUTION OF CHLOROSULPHOACETIC ACID ETC. 233 XXXIX.-Resolution of Chlorosulphoacetic Acid into its Optically Active Components. By HILMAR JOHANNES BACKER and WILHELM GERARD BURGERS. CHLOROSULPHOACETIC acid SO,EI*CHCl*CO,H one of the simplest compounds with an asymmetric carbon atom has hitherto resisted all attempts at optical resolution. Porcher stated (Bull. SOC. cJzi?n. 1902 [iii] 27 438) that resolution is possible but Pope and T 234 BACKER AND BURGERS RESOLUTION OF CHLOROSULPHOACETIC Read repeating his experiments did not confirm his results and were led " to dismiss them as not in accordance with experiment " (J. 1908 93 794; 1914 105 811). We have resolved the racemic acid by a method which apparently had not previously been applied to such purposes namely by slow crystallisation of alkaloidal salts in the cold.After a preliminary examination of their solubility the alkaloid salts of chlorosulphoacetic acid were prepared by treating the sodium salt at room temperature with a soluble salt of the alkaloid in such dilutioii that crystallisation of the product did not start at once and only a small part was subsequently deposited. Since the solubility of the alkaloid salts was so small that the effect of the active chlorosulphoacetic acid on the rotation was inappreciable the sodium and ammonium salts were examined. For purification the same " cold crystallisation " was used. The alkaloid salt was therefore converted a t 0" into the ammonium salt by means of the theoretical quantity of dilute ammonia the alkaloid was filtered off and the solution of the ammonium salt was mixed with the alkaloid (as acetate) in such concentration that again only a part of the alkaloid salt crystallised.By means of yohimbine a dextrorotatory ammonium salt was obtained and an acid of nearly twice the rotation. I-Sjtrychnine gave fhe dextro-rotatory acid whilst d-cinchonine furnished the laevo-component, so that the small rotation we first obtained could not be ascribed to the presence of traces of the alkaloids. The highest constant value of the molecular rotation was for the acid [MI = & 39" and for the neutral ammonium salt [MI = & 20". The acids and their salts gradually racemise in solution a t room temperature.Bases accelerate racemisation of the salts. On evaporation the solutions lose their activity completely. These active acids therefore are more stable than fluorochlorobromo-acetic acid which shows activity only in its alkaloidal salts (Swarts, Bull. roy. Be@. 1896 [iii] 31 25) but they do not attain the high stability of chloroiodomethanesulphonic acid which is not racemised by any of the usual methods (Pope and Read loc. cit.).* E X P E R I M E N T A L . Preparation of Chlorosulphoacetic Acid .-The method used for the preparation of other sulphocarboxylic acids (Rec. trav. chim. , 1920 39 694; 1924 43 297) gives a good yield and a pure product. * This research is being continued and the method will be applied to other resolutions.The present results are published because of the departure of Mr. Burgers.-H. J. B ACID INTO ITS OPTICALLY ACTIVE COXPONENTS . 235 To 94 g. (1 mol.) of freshly distilled chloroacetic acid cooled with ice are gradually added SO g. (1 mol.) of sulphur trioxide with constant shaking. A viscous nearly colourless syrup of the mixed anhydride of sulphuric and chloroacetic acids is formed (Found by titration after decomposition with water equiv. = 57. CH,Cl*CO*O*SO,H decomposed by water into CH,Cl*CO,H + H,SO,, requires a mean equivalent weight of 174.513 = 58.2). The anhydride is converted into the sulphonic acid by warming: CH,C1*C0*O*SO3H -+ SO,H*CHCl*CO,H. At 70" the external heating is discontinued; the heat of reaction causes the tem-perature to rise to about 140" the liquid becoming coloured towards 100" and a feeble evolution of gas (CO and SO,) setting in.The product is a brown syrup consisting mainly of chlorosulphoacetic acid (Found equiv. = 84. Calc. equiv. = 174.32 = 87.2). When kept over-night the acid may crystallise. A solutim of the syrup or crystallised mass in 5 litres of water is t'reated with barium carbonate in excess (200 g.). The filtrate, evaporated to 250 C.C. and cooled deposits 270 g. of pure crystalline barium chlorosulphoacetate (yield more than 80%) (Found : Ea = 41.83 41.84. On concentration the mother-liquor gives as in Andreasch's preparation (Monatsh., 1 SS6 7 158) crystals of barium chloromethanedisulphonate (about 1.5 g.) (Found H20 = 17-37; Ba = 32.56 32.54. Calc. for CIE0,ClS,Ba,4H20 H,O = 17.24; Ba = 32.860/).Chlorosulphoacetic acid was prepared by shaking its barium salt rrzechanically for 1 hour with the calculated quantity of 2AT-sulphuric acid. The filtrate which was free from sulphuric acid and barium was concentrated fist by distillation under reduced pressure then in a desiccator over sulphuric acid and finally over phosphorus pentoxide until crystallisation set in. Chlorosulphoacetic acid forms very hygroscopic crystals containing 1H,O (Found Jl = 191.8. Calc. for C,H,05C1S,H,0 X = 192-56). The melting point determined in an apparatus for hygroscqpic substances (Chem. TYeelcblad 1919 16 1564) was 83". Sormal Alkaloidal Xalts .-The normal salts of chlorosulpho-acetic acid with various alkaloids were prepared either by dissolving the bases in the equivalent quantity of the acid or by double decomposition from sodium chlorosulphoacetate with a soluble salt, usually the acetate or phosphate of the alkaloid.The salts all of which were obtained in the crystalline state,* were titrated with sodium hydroxide in presence of phenolphthalein or thyrnol-p ht halein. Calc. Ba = 41.89y0). * Pope and Read state that the quinine and cinchonine salts were not obtained crystalline. Their strychnine salt contained 1H,O. I" 236 BACKER AND BURGERS RESOLUTION OF CRLOROSULPHOACETIC The normal quinine salt forms a felted mass of small needles containing 4H20 (Found H20 = 8-03 M = 894. requires H20 = 8.05%; M = 895.0). The normal cinchonine salt crystallises with 1H20 in silky needles, concentrically arranged in dense globules (Found H20 = 2.36; M = 780.C2H,0SClS,2C1,H220N2,H20 requires H20 = 2.31% ; M = 780.9). The normal strychnine salt when crystallised from a dilute solution forms needles about & inch long containing 3H20 (Found H20 = 6.08 6.15; M = 896.7 897-2 895.8. C2H,06C1S,2C~,02N2,4H,0 requires H,O = 6.03%; M = 897). d-Chlorosulphoacetic Acid.-Sodium chlorosulphoacetate (0.05 mol.) in 1150 C.C. of water was treated with 33.4 g. (0.1 mol.) of strychnine dissolved in the same volume of water containing 11 g. of acetic acid. Slender needles began to separate within 1 hour and after 10 hours a t 20° 9 g. of strychnine salt were collected corresponding to 20% of the quantity formed (44-8 g.). For polarimetric examination weighed quantities of the strych-nine salt (06-2 g.) were shaken a t 0" with the theoretical quantity of dilute ammonia the volume was brought to 20 c.c.and the solution of the ammonium salt after being extracted four times with half its volume of chloroform was examined by means of a polarimeter (Schmidt and Haensch) with monochromator. In some cases the concentration of the ammonium salt was verified by evaporation of the solution. The rotatory power was measured for X = 589 pp (D) and for two arbitrary wave-lengths in the green (A = 533 pp) and blue (A = 494 pp). The ammonium salt pre-pared from the strychnine salt mentioned above gave the following figures Concentration 0.00480 g.-mol. in 100 c.c.; Z = 2; aD = + 0.18"; [MI = + 18.7". For recrystallisation 4-48 g.(0.005 mol.) of the active strychnine salt were decomposed by ammonia. The separated strychnine was dissolved in dilute acetic acid and added to the solution of the ammonium salt. The total volume being 230 c.c. the concentra-tion was the same as above. 1.3 Grams or nearly 30% separated. Rotation of the ammonium salt Conc. 0.01115 g.-mol. in 100 C.C. ; 1 = 2 ; tcD = + 0*45" as33 = + 0*58" aqD4 = + 0.74" ; [MID = + 20.2" = + 26-0" [MI,, = + 33.2". Conc. 0.00560 g.-mol. in 100 c.c.; I = 2; C C ~ = + 0-23" a533 = + 0*30" a4D4 = + 0.37"; [MID = + 20.5" [M],, = + 26-8" [M'J,, = $- 33.0". Addition of sulphuric acid to liberate the acid (2 mols. for 1 mol. of ammonium salt) increased the rotatory power but this did not chang ACID IKTO ITS OPTICALLY ACTIVE COMPONENTS.237 further on addition of more sulphuric acid. Rotation of the free acid : C'OnC. 0.005 g.-mol. in 100 C.C. ; ,! = 2 ; a = + o.40°,a533 = + o.5?o, 1 - Chlorosulphoacetic Acid .-Sodium c hlorosulp hoac et a t e (0 -0 5 mol.) was mixed with 30 g. (0.1 mol.) of cinchonine dissolved in water containing 9 g . of acetic acid. The total volume was 1150 C.C. After 2 days 5-5 g. of the cinchonine salt or 14% of the total amount (39 g.) had separated. The product was decomposed with ammonia like the strychnine salt the only differeme being that the alkaloid was filtered off before extraction of the solution with chloroform. Rotation of the ammonium salt Conc. 0.00278 g.-mol. in 100 c.c.; I = 2 : The active cinchonine salt (3.9 g.; 0.005 mol.) was recrystallised in the same way as the strychnine salt.From 115 c.c. the same concentration as above there separated 0.95 g. or 257;. Rotatory power of the ammonium salt Conc. 0.00324 g.-mol. in 100 c.c.; I = 2 ; aD = - 0.12" = - 0*17" agg4 = - 0.23"; [AM] = The acid liberated by an excess of sulphuric acid gave the figures : Conc. 0.00305 g.-mol. in 100 c.c.; mD = - 0.23" c1333 = - 0*29", c1494 = -/- 0.62"; [Jf] = + 40" [A$f]533 = + 52" [l!f]gg4 = $- 62". aD = - 0.08" ; f i t l ] D == - 14.4". - 18*5" [ill]533 == - 26.2") [Jf],g4 = - 35.5". aqg4 = - 0.38" ; pi], = - 37-70 [ J ~ I ~ ~ ~ = - 47.50 [N],g = - 62-30. Thus the mean values for the rotatory power are : Chlorosulphoacetic acid [MI = zfr 39" = & 50", h'eutral ammonium salt [il.i'] = & 20" = 36", [MI494 = Zt 62". [&!]494 = & 34". Xacenzisntioiz. The rotation of a neutral solution of the d-ammonium salt contain-ing 0.1 mol. per litre had fallen in a fortnight to half its value. The rotation of a solution containing 0.05 11101. of the d-acid per litre and an excess of sulphuric acid diminished in 10 days by one-fourth. A solution of 0.05 mol. of the ammonium salt per litre containing 0.1 mol. of free ammonia had lost one-third of its rotatory power within 24 hours. The d-acid and the d-ammonium salt each in a solution containing 0.05 mol. per litre were rapidly heated boiled for 1 minute and immediately cooled. Their rotatory powers had decreased by about 5%. The same solutions evaporated on a water-bath and diluted to the original volume racemised completely. Examined a week later it m-as inactive. ORGANIC CHEMICAL LABORATORY, (HOLLAXD ). UNIVERSITY OF GRONINGEN [Received September 8th. 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700233

出版商:RSC    

年代:1925

数据来源: RSC