CCCLXX. -Trypnocidal Action and Chemical Con-stitution. Part I I L Arsinic Acids Containing the Glyoxaline Nucleus. By ISIDORE ELKAXAH BALABAN and HeLaom Kma. IN Part I of this series (J. 1924 125 2595) it was shown that the three isomeric monoaminobenzoyl derivatives of 4-aminophenyl-arsinic acid showed some trypanocidal activity when tested on experimental trypanosomiasis in mice but were not permanently curative. In Part 11 (this vol. p. 2632) it was shown that per-manent curative properties appeared when a methoxy-group waa present in the para-position in the benzoyl group in the mono-aminoarsinic acids or when there were two amino-groups present, one in each nucleus. It was therefore thought of interest to prepare q1yodint?-4'(or 5')-carbox~-p-ami~henyEarsinic mid (I) and it 2702 BALABAN A?XD KING TRYPANOCIDAL ACTION 3-amino-derivative (11) both of which would resemble in build and amphoteric character the amides mentioned above.It was hoped m* As0 H /-\NH*CO-Y=$!H “H As0 H /-\NH-CO*$Z==YH N NH 2\-/ 2\-/ that the presence of the glyoxaline nucleus would lead to a more favourable-as regards the trypanocidal action4tribution of the amides in the tissues especially as the glyoxaline nucleus is con-tained in or associated with certain substances of remarkable physiological activity such as histamine insulin and the pituitary active principles. Both these arsinic acids have been prepared, the fkst by application of the Bart-Schmidt reaction to glymline-4(or 5)-curboxy-p-aminoanilide and the second by nitration and subsequent reduction of the parent arsinic acid.The maximum dose tolerated by mice and the minimum curative dose on an experimental infection of Trypmsonza equiperdum in mice expressed in milligrams per gram of mouse of these two glyoxaline arsinic acids as compared with 3‘-a&obenzoyl- and 3 3‘-diaminobenzoyl-p-aminophenylarsinic acids is shown below, Dosis toleratu ............... 1.25 3-0 0.6 >3-5 D O S ~ c~mtiva ............ 0-8 1.5 0-3 2.0 I. II. 3’-NH,. 3 3’-diNH,. ( r = 7) r signifsing the number of days the blood stream remains free from parasifes. It will. be observed that glyoxaline-4’(or 5’)-carboxy-p-aminophenylminic acid (I) unlike 3’-aminobenzoyl-p-aminophenylaminic acid has permanent curative properties and the enhanced curative properties of 3 3’-diaminobenzoyl-p-amino-pheny1a;rsinic acid are surpassed in 3-aminoglyoxaline-4’(or 5’)-carboxy-p-aminophenylarsinic acid (11).Glyoxaline-4’(or 5’)-carboxy-o-aminophenylarsinic acid isomeric with the above described para-derivative cannot be prepared by the application of the Bart-Schmidt reaction to gZyoxaZine-4(or 5 ) -carboxy-o-aminoanilide because treatment with nitrous acid gives rise to a crystalline diaxoimide (111). In the same way the amino-arsinic acid (11) gives rise In the crystalline diazoinZide (N). (G = glyoxalinyl AND CHEMICAL CONSTITUTION. PART III. 2703 Neither of these substances couples with alkaline @-naphthol; their constitution follows from the exact analogy of their formation with Biissneck’s 4-acetyl-3 Ptolylenediazoimide the constitution of which was elucidated by Morgan and Wcklethwait (J.1913, 103 1394). The diazoimide (III) is of especial interest because its formation w i l l serve to detect nitrous mid as a crgsfalline derivative a t a dilution of 1 in 6400. In the above derivatives the glyoxaline nucleus is joined to the phenyl nucleus by an amide link. The researches of +an and his amociatea have rendered available five isomeric nihphenyl-glyoxalines without an intermediate chain of atoms. These have now been reduced to the corresponding amino-derivatives- and submitted to the Bart-Schmidt process for introducing the arsinic acid group. 2-m-Aminophenylglyoxuline and 2-p-arninophenyl-glyozaline (V) so prepared give no recognisable trace of mink acids under a variety of experimental conditions.This result may be paralleled with Schmidt’s inability (Annulen, 1920 42l 168) to replace the amino-group in p-aminodiphenyl (PI) by the arsinic acid group although o-aminodiphenyl gives a 60% yield of the arsinic acid by the same reaction (Aeschlimann Lees, McCleland and Nicklln this vol. p. 68). This diiliculty in the case of substances containing the glyoxaline nucleus is clearly due to the fact that the most favourable conditions for carrying out the Bart-Schmidt reaction-neutrality or weak alkalinity-are precisely those which lead to coupling internal or otherwise of the glyoxaline nucleus present with the diazotised base. This is plainly shown in several of the cases tried by the concomitant separation of insoluble highly coloured amorphous presumably azo-compounds.The marked change of physical properties associated with N-methybtion of glyoxahes led to the preparation of 2-p-nitro-~knyl-l-methylglyoxaline with a view to its reduction and sub-seqw& tm&ment by.the Bart-Schmidt reaction. The pbor yield of monomethyla;ted product however led us t o abandon the scheme. Another avenue of approach suggested itself in the prior methylation of 2-phenylglyoxaline followed by nitration reduction and indirect amination. Here again the yield of monomethylafed product (Vn) wa only l S ~ o the main product apart from unchanged material being 2-pknyl-l -methylglyoxaline mthochlmide (VIII) 2704 B A A N AND KINQ TRYPANOCIDAL ACTION which although the salt of a quaternary base is precipitated as an oil on addition of strong alkali to its aqueous solutions.Z-P?ienyl-l-methylgZyoxaline (VII) which is also formed by dry distillation of the methochloride (VIII) under reduced pressure, forms an abnormal gold salt by crystallisation of the precipitate it yields with chloroauric acid from water containing a little acetone. The constitution of this modified gold salt RAuC13 is similar to that of several others which have been described. The two types are readily interpreted on the electronic basis. The normal salts have the structure (IX) analogous to ammonium salts whilst the abnormal have the structure (X) analogous to that of trimethyl-amine oxide. 2-o-AminophenylgZyoxaline reacts with nitrous acid with produc-tion of a crystalline tricyclic 1 2 3-triazine (XI) which does not couple with alkaline p-naphthol in exactly the same way as o-amino-phenylperimidine yields the triazine (XII) (Sachs and Steiner Ber., 1909 42 3675)./-\ ":N 4 -p - Amimphen y Zgly oxaline submitted to the Bart - Sc hmidt reac -tion yields a very small amount of 4-phenyEgZyo~Zine-p-arsinic acid, the main product being a purple dyestuff. The arsinic acid was not obtained in sufEcient quantity for trial on experimental trypano-somiasis. This was unfortunate as its structure (XIII) bears a close resemblance to the pyrazolone (XIV) derivatives of which are at present on the market for the treatment of protozoal diseases. (=.I (m.) The isomeric 4-o-amimphenylgZyoxaZine on diazotisation yields a non-coupling yellow triazine structurally related to (XI).The chief interest however in 4-o-aminophenylglyoxaline lay in the remote possibility of its resolution into enantiomorphs. Pyman has produced a considerable body of evidence for the resemblance between glyoxaline and benzene so that the substance under con-sideration being related to diphenyl should if Kaufler's ideas b AND CaEMltCAL CONSTITUTION. PABT Ill. 2705 applied to it be resolvable. The other type of formula the non-coplanar type suggested by Kenner as an explanation to be con-sidered in the interpretation of his results would in the present instance not lead to enantiomorphs. 4-o- Aminophenylglyoxaline has been fractionally crystallised from water a t low temperatures as its nomnal d-tartrate and as its dimmphor-lO-sulphte but in neither case was there any evidence of resolution.Several attempts have been made under a variety of conditions to introduce arsenic directly into the glyoxaline nucleus but hitherto unsuccessfully. The Bkhamp reaction (heating with arsenic acid) has been applied to glyoxaline 1 -methylglyoxaline 2-phenyl- and 4-phenyl-glyoxalines whilst the action of arsenious chloride with or without addition of aluminium chloride has been examined on glyoxaline 1 -methylglyoxaline and 4-phenylglyoxaline. We are much indebted to Miss F. M. Durham and Miss J. Marchal for the care exhibited in determining the therapeutic action of the arsinic acids herein described and to Prof. Pyman not only for freely allowing us to work in this field and for placing at our service unpublished results which materially assisted the investigation but also for a gift of 4-o-nitrophenylglyoxaline.E x P E R I M E N T A L . Nitration of Glyoxaline-4(or 5)-carboxyanilide.-The nitrate separating from water is dimorphous both forms crystallking with +H,O (a) unstable flu@ needles loss at 100" = 4.3; (b) stable, stout prisms m. p. 170-171" (decomp.) loss a t 100" = 3.4: Theory for *H20 = 3.5%. Found in dry salt by nitron estimation, HNO, 25.1 (Theory requires €€NO, 25.2%). The nitrate (75 g.) was added gradually and with ice-cooling to 150 C.C. of concentrated sulphuric acid. The product was kept for 3 hours at room tem-perature and then poured into ice-water ; the solid obtained (55.5 g.), m. p. 265" (decomp.) recrystallised twice from 700 C.C.of N-hydro-chloric acid gave 33.8 g. of glyodine-4(or 5)-carboxy-p-nitroaniZ& hydrochloride. A further 4-7 g. were obtained from the mother-liquors. The.sulphuric acid mother-liquors were heated a t 80" and frac-tionally precipitated by addition of sufficient strong alkali to produce a slight separation of solid from the hot solution and copious crystailisation when cold. The process was repeated until all acidity waa removed final neutralisation being effected by saturated sodium carbonate. Several crops of almost pure glyomline-4(or 5)-curboxy-o-nitroanilide m. p. 229" were thus obtained. This was finally purified aa hydrochloride. The h a 1 mother-liquors of the fractionation gave 1-0 g. of p-nitroaniline (m. p. 147"). VOL.CXXVIT. 4 2706 BAIABAN AND KING TRYPANOCIDAL ACTION In all 38.5 g. of the pisomeride and 15.4 g. of the o-isomeride were obtained in a pure state as hydrochlorides yields of 36 and 14.3% respectively. Gl yo~aZi~~-4( or 5) -curbox y - p-nitroanilide hydrochloride mono-hydrate crystallises from N-hydrochloric acid in which it is sparingly soluble in long colourless rectangular prisms or tablets decomposing about 298". It also crystallises in f l u e needles which on standing in contact with the solution pass into the previously described stable variety (Found loss a t 95" 1.9; C1 12.4. CloHs0,~,,HCl,H20 requires C1 12.4%. When dried a t 110" the salt suffers complete loss of water and partial loss of hydrogen chloride. Found: loss 7.4; C1 12.1. The monohydrate requires H20 6.3%.ClJIsO~4,HCI requires CI 13.2%). The base crystallises from glacial acetic acid in long colourless plates m. p. 307" (COIT.) which contain two mols. of acetic acid (Found loss a t 95" 37.1; on dried solid C 51.7; H 3-5. cloHso,N4,2c2~402 requires loss 34-1 %. C10HS03NP requires C 51.7; H 3-4y0). It is practically insoluble in water and the usual organic solvents except acetic acid. It dissolves in 2N-sodium hydroxide with a pale yellow colour and is reprecipitated by carbon dioxide. It forms a sparingly soluble nitrate m. p. 205" (decomp.). Glyoxaline-4(or 5)-carboxy-o-nitronilide crystallises from glacial acetic acid in bright yellow glistening plates m. p. 229" (Found : C 51.3; H 3.5. C10H,03N4 requires C 51.7; H 3.4%). It is practically insoluble in water and the usual organic solvents except acetic acid.In 2N-sodium hydroxide it dissolves with an intense yellow colour and is precipitated by carbon dioxide as glistening, yellow needles. The nitrate from 2N-nitric acid crystallises in long y~llow prisms m. p. 196" (decomp.). The hydrochloride crysfalhes from N-hydrochloric acid in which it is moderately easily soluble in yellow rectangular? anhydrous prisms (Found : c1 13.0. Hydrolysis of the Nitro-wmpoud.-2.0 Grams of each hydro-chloride were boiled for 3 hours with 20 C.C. of 16% hydrochloric acid. Extraction with ether isolated p - and o-nitroaniline respec-tively? which were identified by the melting points of mixtures with authentic specimens. The mother-liquors were partly basified ; glyoxaline-4(or 5)-carboxylic acid was then isolated effervescing a t 275" (alone or mixed with an authentic specimen).Glyoxuline-4 (or 5) -carboxy - p -aminoanilide Dih ydrochloride. -Twelve grams of the hydrochloride of the p-nitroanilide were added to a mixture of 75 C.C. of concentrated hydrochloric acid and 75 C.C. of alcohol containing 30 g. of hydrated stannous chloride in solution. On heating at 80" a bulky pale yellow precipitate separated? which CloHsO,N,,HCl requires c1 13.2%) AND CHEMICAL CONSTITUTION. PART III. 2707 dissolved on addition of more alcohol. On cooling 15.6 g . of the sttznnichloride of the amino-base m. p. 290" (decomp.) separated, and a further 2-3 g. on concentration of the mother-liquors. After removal of tin as sulphide the dihydrochZur& of the base 9-55 g.or 80% of theory was isolated. This salt crystallises from dilute hydrochloric acid in colourlw glistening rectangular prism which blacken a t about 290" and crystallise with one molecule of water (Found loss 6.1 ; on anhydrous salt Cl 25.9. Cl,,HloON4,2HC1,~0 requires H,O 6-1 %. CloH100N4,2HCl requires C1 254%). The diazotised salt couples with alkaline @-naphthol with production of a red solution. The base is precipitated by addition of sodium carbonate solution. It is moderately soluble in water and crystal-lises in colourless glistening delicate plates m. p. 228". The picrate crystallises in long h e yellow needles darkening a t 256" and decomposing a t 266" and is very sparingly soluble in boiling water (Found K O 5.7; on hied salt picric acid estimated by nitron 53.0.CloHloON4,C,H,07N3 1&H,O requires q0 5-9 %. CloHloON4,C,H307N3 requires picric acid 53-1 %). C1yom~ine-4(or 5)-mrboxy-o-aminoanilide DihydrocUoride.4i.x grams of the hydrochloride of the nitroanilide were reduced in the same way as the p-nitroanilide. On keeping the stannkhloride (11.0 g.) separated in colourless rectangular prisms and on con-centration another 2-0 g . were obtained. On removal of tin as sulphide and concentration to a low bulk glyoxalinecarbozy-o-aminoanilide &hydrochloride crystallised out (yield 5-4 g. or 87.5%). This salt crystallises from dilute hydrochloric acid in long, rectangular prisms which decompose at 310" and crystallise with one-half a mo.2ecule of water (Found loss a t loo" 3.6.Cl,,H,,0N4,2HC1,~H,0 requires H,O 3.2%. Found on dried salt C1 25.5. Cl,€€l,0N4,2HC1 requires C1 25.8%). It is very readily soluble in water and on addition of sodium nitrite a diazo-imide (111) crystallises out. This is sparingly soluble in boiling acetic acid ethyl alcohol or benzene somewhat more readily soluble in boilmg methyl alcohol from which it separates in fine needles, m. p. 195-196" but varying with the rate of heating. The diazo-imide is soluble in sodium hydroxide solution but not in sodium carbonate and forms an insoluble hydrochloride with concentrated hydrochloric acid but dissolves on dilution. It produces no colour on addition to alkaline /%naphthol solution. It is very sparingly soluble in water and will detect nitrous acid as a solid crystalline derivative a t a dilution of 1 in 6400 in the presence of sodium acetate or conversely the anilide can be detected a t a dilution of 1 in 5OOO.The amino-base is precipitated on careful addition of sodium 4x 2708 B U B B N AND KING TRYPANOCIDILL ACTION carbonate to the dihydrochloride. It is moderately easily soluble in boiling water and crystallises in h e needles m. p. 270" with previous darkening. The dipicrate is very sparingly soluble in boiling water and crystallises in minute needles m. p. 242" (decomp.) (Found H,O 5.9 5.6; on drid-Balt picric acid 70.8 71.0. Cl,,E,,0N,,2C,H30,N3,2~€&0 requires H,O 5-8 %. requires picric acid 69.4%). Glyoxaline-4'(or 5')-carboxy-p-aminophenylarsinic Acid (I).-Gly-oxalinecarboxy-p-aminoanilide dihydrochloride (27.3 g.) (in 5 batches) was dissolved in 150 C.C.of water cooled to 0" and diazo-tised by addition of 100 C.C. of 10% sodium nitrite solution. To the clear solution 9.0 g. of arsenious oxide in 70 C.C. of 2N-sodium hydroxide were added to produce a faintly alkaline reaction. A light brown precipitate separated and a considerable amount of frothing took place. After keeping over-night the solution was w-armed on the water-bath and filtered from coloured by-products. The filtrate was fractionally precipitated with strong hydrochloric acid and after removal of amorphous material a crystalline crop separated. On keeping 11.2 g. (36% yield) of crude arsinic acid were obtained. It crystallised from 75% acetic acid (50 vols.) in pale yellow glistening triangular leaflets which darkened at 280".This acid is almost insoluble in boiling water or glacial acetic acid, dissolves more readily in mixtures but is readily soluble in boiling 25% formic acid separating in needles forming a very stable monohydrate (Found on various samples loss a t 105" 0.7; As, 22.4 22.4 22.8. C10H100,N3As,H,0 requires As 22.8%). A 1% solution in 0-2N-ammonia treated with a tenth of its volume of 5% magnesium or calcium chloride gave an immediate precipitate of the magnesium salt in h e needles but the calcium salt separated in anisotropic spheroids only on heating. The sodium salt crystal-lises in needles and the hydrochloride in fine needles. Glyoxaline-4'(or 5')-carboxy-p-amino-3-nitrophenylarsinic Acid.-Glyoxalinecarboxy-p-aminophenylarsinic acid (9.9 g.) was dissolved in 30 c.c of sulphuric acid a t 0" and nitrated by addition of 3.g. of nitric acid (d 1-42) dissolved in a few C.C. of sulphuric acid. When the mixture was poured on to ice the crude nitro-acid (10.5 g.) separated a t first in leaflets but later in needles. The mother-liquors neutralised to Congo-paper and kept at 0" for 3 days, deposited a further 2-0 g . of nitro-acid. The pure nitro-acid is best obtained by crystallisation from 50% acetic acid. It is almost insoluble in boiling water or boiling glacial acetic acid. From 25% formic acid it separates in clusters of yellow plates m. p. about 327" (decomp.). It forms a very stable monohydrate (Found: C10H100N4~2C6H307N AND CHEMICAL CONSTITUTION. PART III.2709 lorn a t 110" 0.9; on two distinct samples of dried acid As = 19-8, 19.9. C1,€&0,N4~,H,0 requires As 20-O~o). 1% Solutions in O.2N-ammonia were treated with a tenth of the volume of 5% lithium magnesium calcium or barium chloride ; a micro-crystalline precipitate of the magnesium salt formed immediately the calcium salt separated almost immediately in fine needles and the barium salt also in fine needles especially on rubbing the walls of the vessel. The lithium salt separated after keeping for several days. Hydrolysis of the Nitro-aci&.-'P,o grams of the pure acid were boiled for 30 minutes with 30 C.C. of N-sodium hydroxide and the solution was cooled and made neutral to Congo-paper. Successive crops of acids were obtained which by suitable crystallisation from water gave eventually an 86 yo yield of 3-nitro-4-aminophenylarsinic acid and an 83% yield of glyoxalinecarboxylic acid.There was no evidence for the presence of isomeric nitro-acids and no definite evidence was obtained from fractional crystallisation of 10 g. of crude glyoxalinecarboxy-p-aminonitrophenylarsiic acid. Glyomline-4'( or 5 ') -carboxy-p-amino-3-aminophenyZarsinic acid (11) was prepared by dissolving 8.0 g. of the nitro-acid in 80 C.C. of 2N-sodium hydroxide at - 5" adding gradually 28 g. (7 mols.) of ferrous chloride in 40 C.C. of water and and finally 80 C.C. of 2N-sodium hydroxide. After filtration the ferric hydroxide was extracted thrice with 150 C.C. of 0-2N-sodium hydroxide. The combined filtrates were neutralised to Congo-paper and the crude amino-acid (5.65 g.) which separated crystalline was collected.The mother-liquors were made alkaline with ammonia and heated with magnesium chloride. The magnesium salt which separated was dissolved in 50 C.C. of N-hydrochloric acid and the acidity removed by sodium acetate. The amino-acid so obtained weighed 0.85 g. The total yield of crude amino-acid was 86%. It was purified with diEculty by dissolving in 0-527-hydrochloric acid and cautiously adding saturated sodium acetate solution until the solution was only faintly acid to Congo-paper. This caused the gradual separation of a green flocculent substance which could be filtered off; the amino-acid was precipitated from the filtrate by further addition of sodium acetate. The pure amino-acid crystal-lises in h e long colourless rectangular prisms which are unmelted a t 320".They contain half a molecule of water not lost a t 100" (Found As 22.4 22.2. Cl0HllO4N4As,#&O requires As 22.4%). In hydrochloric acid solution addition of sodium nitrite causes an immediate precipitation of a crystalline diazoimide (IV) which separates from dilute solutions in microscopic leaflets. The diazo-imide does not couple with p-naphthol. A 1% solution of the amino-acid in 0-227-ammonia treated with one-tenth its volume o 2710 BALABAN AND KING TRYPANOCIDAL ACTION 5% magnesium or calcium chloride gave an immediate precipitate of the magnesium salt in fine needles whilst the calcium salt was precipitated in crystalline tufts only on 'heating. 2-p-Aminophenylglyoxline dihydrochloride (V) was obtained by reducing 19.0 g.of 2-p-nitrophenylglyoxaline with 68 g. of stannous chloride in 170 C.C. of concentrated hydrochloric acid. The stunni-chloride separated in colourless needles after digestion on the water-bath. Its de-tinned solution on concentration gave 16.2 g. of the pure dihydrochloride crystallking in colourless rectangular prisms which darken at about 300" (Found C1,30.5. Cg€&N,,2HCI requires C1 30.6%). It diazotises and couples with alkaline B-naphthol forming a deep red solution and also gives an intense red solution with Pauly's reagent. The free base is an oil which turns brown on exposure to air The monopicrate is very sparingly soluble in water and crystallises in orange glistening rectangular plates decomp.about 238" (Found picric acid by nitron 58.7. C,HgN3,C6H,0,N3 requires picric acid 59-Oy0). Under no con-ditions could any arsinic acid be isolated by the application of the Bart reaction to this aminophenylglyoxaline. Action of Methyl Sulphate on 2-p-hTitrophenylglyoxaline.-The base (12.6 g.) was heated a t 100" with 8.4 C.C. of methyl sulphate for 1 hour. After initial liquefaction the product set to a cake. The solid obtained on treatment with sodium hydroxide was crystal-lised as hydrochloride; 6.0 g. of the hydrochloride of the initial material were recovered. The hydrochloride mother-liquors on being basified gave 1.0 g. m. p. below 120". This was 2-p-nitro-phenyl-1 -mthylglpoxaZine and when recrystallised from water it separated in long pale yellow silky needles m.p. 116.5" (corr.). It is moderately soluble in boiling water sparingly so in ether and very soluble in alcohol benzene or chloroform. The chlorouurute crystallises from 3N-hydrochloric acid in golden-yellow irregular prisms which decompose a t 226" (corr.). It is soluble to the extent of 1 in 300 in the boiling acid (Found Au 36-4. C,,H90,N3,HAuC14 requires Au 36.3%). The hydrochloride crystallises in elongated plates and is very soluble in water. The nitrate crystallises in diamond-shaped plates effervescing at 186" (corr.). It is moderately soluble in water but sparingly soluble in dilute nitric acid. The picrate crystallises from alcohol in which it is very sparingly soluble in fine glistening needles m. p. 212" (corn.) (Found: picnc acid by nitron 53-1.CI,Hg0,N,,C6H,0,N3 requires picnc acid 53.0 yo). 2-m-Aminophenylglyoxaline dihydrochloride was obtained by reducing 7-0 g. of the m-nitrophenylglyoxaline with 25 g. of stannous chloride in 64 C.C. of concentrated hydrochloric acid and 30 C.C. o AXD CHEMICAL CONST~UTION. PABT ITI. 2711 alcohol on the water-bath. When cold the stannichloride separatd in rectangular prisms which after de-tinning and concentration, gave 6-2 g. of the pure dihydrochloride. This salt is a numohydrate and melts with decomposition a t 282". It is very solubJe in water, less soluble in acid solutions (Found loss 7-3; on dried salt, C1 30.5. C,€&,N3,ZHC1,H,0 requires H,O 7.3%. C,€&N3,2ECl requires C1 30.6%). After diazotisation it couples with alkaline p-naphthol with an intense red colour.The base liberated by addition of sodium bicarbonate is very soluble in water. It is a monohydrate which partly melts with effervescence between 130 and 140" and finally melts at 202-203". When dried at 95" it melts a t 203-204" (Found loss a t 95" 9.1. C,H,N,,H,O requires H,O 10.2%). The anhydrous base is sparingly soluble in boiling acetone benzene or ethyl acetate and readily soluble in hot alcohol, from which it crystallises in h e needles. The monopicrate crystal-lises from water in which it is very sparingly soluble in long spikes, decomp. 218" (Found picric acid by nitron 58-0. c,&N3,c6H30,N, requires picric acid 59.0%). Attempts to replace the amino-group in this base by the arsinic acid group by the Bart reaction were all unsuccessful.~-o-Aminophenylglyo~line dihydrochloride was prepared from the nitro-compound by reduction with stannous chloride the stunnichluride separating in thin plates. The dihydrochloride (Found: C1 30-5. C$BP3,2HC1 requires C1 30.5%) crystallised in large, glassy tablets melting at 234-236" and decomposing a few degrees higher. It was readily soluble in water and on addition of sodium nitrite gave a triazine (XI) crystallising in needles m. p. 113-114". This triazine is insoluble in alkali but immediately soluble in concentrated hydrochloric acid. From 3N-hydrochloric acid the hydrochloride of the triazine crystallises in needles. The triazine does not couple with alkaline p-naphthol. The nzmmpicrute of the o-base is readily soluble in boiling water and crystallises in small, feathery needles m.p. 211-2112' (without decomp.) (Found: picric acid 59-6. C,H,N3,C6H,0,N3 requires picric acid 59.0y0). The base melts at 136-137" and crystallises from water in large, white fern-like crystals. 4-p- Aminophenylglyoxuline dihydrochhde was prepared by reduc-ing the p-nitro-base (19 g.) by 68 g. of stannous chloride in 170 G.C. of concentrated hydrochloric acid and 50 C.C. of alcohol on the water-bath a t 80". The &unnichluride (needles darkening a t 310") crystal-lised from the hot solution. After removal of tin as sulphide, 17.1 g . of pure dihydrochloride were obtained in colourless glistening needles which darken a t 310" (Found C1 30.5. C,v3,2HCl requires C1 30.6%). It is readily soluble in water and whe 2712 BALABAN AND KING TRYPANOCIDAL ACTION diazotised gives with alkaline p-naphthol an intense purple dye; but a similar colour is obtained with the diazotised base and sodium hydroxide alone.It gives an intense red colour with Pauly's reagent. The base crystallises from water in which it is moderately soluble in glistening hexagonal plates m.p. 98" (corn.). The dipicrate crystallises from water in which it is very sparingly soluble, in yellow needles m. p. 240" (decomp.) (Found picric acid 73-9. C,v3,2C,H30,N3 requires picric acid 74.2 yo). GlyomZine4(or 5)-phenyZ-p-arsinic acid (XIII) was obtained by addition of sodium nitrite to 4-p-aminophenylglyoxaline dihydro-chloride (10 g.) at 0" and subsequent addition of 6.6 g. of arsenious oxide in 36 C.C.of 2N-sodium hydroxide. An intense dark purple solution was formed but the reaction of the solution could be adjusted to neutrality by use of glazed litmus paper. When the evolution of nitrogen had ceased the solution was warmed on the water-bath and the insoluble dyestuff filtered off. The solution was made neutral to Congo-paper and after removal of amorphous material was concentrated. The arsinic acid separated in reddish-yellow plates which were unmelted a t 310" (yield 0.5 g.). On crystallisation from glacial acetic acid,dt separated in dense yellowish-brown prisms. The amount of material was insufficient for analysis but served to confirm its identity. Further experiments under a variety of conditions resulted in no improvement of the yield.This acid gave an intense reaction with Pauly's reagent. Its ammoniacal solution gave an amorphous magnesium salt on heating but the calcium salt separated in the cold in sphaero-crystals. The barium and lithium salts were soluble. From alkaline solutions the acid is precipitated by addition of mineral acid in colourless elongated leaflets. 4-o-Aminophenylglyoxaline dihydrochloride was obtained by reduc-tion of the nitro-base by stannous chloride in concentrated hydro-chloric acid. On removal of tin and concentration the dihydro-chloride monohydrate separated in colourless prisms which effervesce a t 256" and do not lose the water of crystallisation at 95" (Found : C1 29.1 29.1. C,&N3,2HC1,H,0 requires C1 29.2%). It is very soluble in water and with sodium nitrite gives a bright yellow solution from which the triazine separates in clusters of microscopic needles.It does not couple with alkaline p-naphthol and is not soluble in alkali. The base separates as an oil on addition of sodium hydroxide but a slight excess of sodium bicarbonate causes it to crystallise in square plates m. p. 131". It is soluble in water, sparingly soluble in ether and is unaffected by excess of sodium hydroxide. The dipicrute crystallises in elongated plates from water in which it is sparingly soluble and decomposes about 200 BND CHXMICAL CONSTITUTION. PABT III. 2713 (Found picric acid by nitron 73.5. C&&N3,2C6H30,N3 picric acid 74.2%). The wmal tartrate sepamtes in felted needles from aqueous solutions containing molecular proportions of the constituents or one molecular proportion excess of tartaric acid.Repeated crystallisation a t temperatures below 40" failed to effect any change in its rotation or melting point. It crystallises with 1.5H20 and loses 1€&0 in a vacuum over sulphuric acid. When air-dried or dried in a vacuum it melts at 95-97" and then effer-vesce~ a t about 130" [Found loss in a vacuum 5.3; on vacuum-dried material c 49.1; H 5.1. (for loss of 1H20) H,O 5.4%. C,H9N3,C4H606,~H20 requires C 49.1 ; H 5-1%]. The specific rotation was determined in water : c = 0.914; 1 = 2 ; a + 0-27"; + 14.8". The di-d-cumphor-lO-sulphonate is readily soluble in water from which it crystallise~ in anhydrous needles m. p. 198-200" (Found S 10.1. C&&N3,2CloH,,04S requires S 10.0%).The rotation was un-changed after recrystallisation from water below 40" c = 1.0; 1 = 2; a + 0.4Z8"; [a]5461 = + 21.4" c = 2-04; 1 = 2; a + 0.868"; [a]sa61 = $7 21.3"; whence [MI,, = 133.1". Graham (J. 1912,101 747) gives for the molecular rotation of the camphor-sulphonic ion = 66-5; whence for two ions = 133.0" a value identical with that observed for the above salt. Methylation of 2-PhenylgZyoxaline.-Methyl sulphate (28 c.c.) was added in small quantities to 40 g. of 2-phenylglyoxaline with cooling. A vigorous reaction ensued and the mass liquefied. After heating for 30 minutes on the water-bath the product was treated with 20 C.C. of water and mixed with sodium nitrate and nitric acid. On concentration an oily layer separated which deposited 11.2 g.of a nitrate m. p. 126"; this on recrystallisation gave eventually 8.5 g. of unchanged 2-phenylglyoxaline and from its mother-liquors 1.3 g. of 2-phenylglyoxaline picrate m. p. 234" and 1.0 g. of a new picrate m. p. 132". The original nitrate mother-liquors were concentrated further made alkaline with sodium hydroxide, and extracted with chloroform. The chloroform was extracted twice with water ; the aqueous solution on evaporation with hydro-chloric acid gave 15.5 g. of 2-phenyl-l-met~y~lyomline metho-chloride (VIII). The chloroform extract distilled a t 20 mm., gave 9-4 g. of an oil b. p. 190" from which alcoholic picric acid produced 27 g. of picrate m. p. 124". On recrystallisation from water 19.2 g. of 2-phenyl-1-methylglyomline picrate m.p. 132", were obtained and from the mother-liquors 1.6 g. of 2-phenyl-glyoxaline picrate m. p. 232" with various small crops of mixed picrates. 2-Phenylglyoxaline 2-phenyl-1 -methyIglyoxaline and C,~N3,C,H606,1~H20 4 x 2714 TBYPANOCLD~~ ACTION AND cmauc~z~ CONSTITUTION. PUT m. 2-phenyl-1 -methylglyoxaline methochloride were obtained in yields of 32.3 18.2 and 26.7% respectively. 2-Phenyl-l-methylg2yowlline (VII) is a viscous pale yellow oil, b. p. 175'115 mm. with a strong but not unpleasant odour. It is not soluble in water but soluble in organic solvents. The chloro-aurate is practically insoluble in water alcohol or 3N-hydrochloric acid but can be recrystallised from the first-named by addition of a little acetone. It separates in deep yellow elongated prisms, m.p. 189" (con.) (Found Au 42.8. CloHl,,N2,AuC13 requires Au 42.7%). The nitrate is a very soluble salt crystallising in needles m. p. about 100". The picrate separates from 60 parts of boiling water in glistening elongated plates m. p. 133" (corr.). It dissolves three times as readily in boiling alcohol (Found picric acid 59.3. CloHl,,N2,C,H30,N3 requires picric acid 59.2 %). The hydrochloride is extremely readily soluble in water or alcohol and separates in needles (Found loss in a vacuum 14.9; on dried material C1 18.4. CloH,,,N,,HCl,2H20 requires H,O 15.6%. Cl&Xl$2,HC1 requires C1 18.2%). The hydrogen omlate crystal-lises from alcohol in colourless long needles m. p. 135" (corr.). It is readily soluble in water and hot alcohol [Found N 11.0 (Kjeldahl). Cl,Hl~2,C2H20 requires N 11-3%]. 2-Phenyl-1 -methylglyomline methochloride was obtained in small, very hygroscopic needles m. p. 272" by dissolution in absolute alcohol and addition of ether (Found H 6.2; N 13.7; C1 16.7. CloH,,,N2,CH3C1 requires H 6.2 ; N 13.4 ; C1 17.0%). On addition of strong alkali to an aqueous solution the quaternary base is precipitated as an oil. The chloroaurate crystallises from dilute hydrochloric acid in which it is very sparingly soluble in pale yellow elongated leaflets m. p. 134" (corr.) (Found Au 38.5. CllH13N2,AuC14 requires Au 38.5%). Distillation of 2-Phenyl-1 -methylglyoxaline Methmhloride.-Five grams of this salt were distilled a t 15 mm. 2-Phenyl-l-methyl-glyoxaline distilled over a t 175" in 56% yield. It was converted into the picrate m. p. 132" and proved to be identical with that described above. We are indebted to Mr. W. Anslow for the majority of the analyses THE NATIONAL h s m m FOR MEDICAL RESEARCH, recorded in this paper. HAXPSTEAD N.W. 3. [Received September 15th 1925.