4 MORGAN AND MICKLETHWAIT : THE DIAZO-DERIVATIVES OF 11.-The Dicszo-derivatives oj' 1 : 5- and I : 8-Benzene- .suZphonylnapht h y Zenediamines. By GILBERT THOUAS MORGAN and FRANCES MARY GORE MTCKLETHWAIT. T m interactions of the diamines of the benzene series with nitrous acid afford a striking illustration of the influence of orientation on the properties of aromatic compounds. The ortho-diamines and their mono-acyl derivatives yield cyclic diazoimides which are generally colourless * and very stable towards hydrolytic agents, and although until recently condensation had not been detected among the para- diamines, yet about a year ago the authors obtained from the aryl- sulphonyl derivatives of these bases a new series of diazoimides which differ from their ortho-isomerides in having a distinctly yellow colour, and in readily undergoing fission on treatment with acids, phenols, or aromatic amines, the acids regenerating the diazonium salt, whilst the phenols and aromatic amines give rise to azo-derivatives (Trans., 1905, 87, 73, 921, 1302).The formation of these two series of diazoimides indicates very forcibly the profound mutual influence exercised by the substituents when they occupy the ortho- or para-positions of the aromatic nucleus, for in the meta-series this tendency for the diamines and their acyl derivatives to yield diazoimino-compounds by internal condensation seems to be absent. The marked differences in the physical arid chemical properties of the two series of diazoimino-derivatives point to fundamentally dis- similar configurations for the two groups of substances, and, as was stated in the firs5 communication on this subject (Eoc.cit., p. 73), the ortho-compounds which are at once formed, even in the presence of strong mineral acids, may be formulated either as diazoimides or as diazonium-imides, whereas the para-derivatives, which are produced only in faintly acid or neutral solutions, might be regarded as being * 2 : 3-Diazoimi1ioiiaplitlielenu is, however, described as being a yellow compound (Friedlmder aud Zakrzewki, Ber., 1S94, 27, 765).1 : 5- AND 1 : 8-BENZENESULPHONYLNAPHTHYLENEDTAMINES. 5 either diazoimides (I) or imitlo-~-quinonec\ittzides (II), the conditions of formation in this case excluding the dinzonium configuration. I. Hitherto no experimental evidence has been forthcoming to enable one to decide between these two formulz for the para-diazoimides, for although the former sufficed to explain the formation and modes of fission of these substances, yet their colour and great reactivity suggested a quinonoid structure.This question of the constitution of these coloured reactive para- diazoimides has now been put to the test of experiment by extending the investigation to the benzenesnlphonyl derivatives of two of the heteronucleal naphthylenedianiines. Benxenesulphonyl-I : 5-nc6phtl~yzenediamilze (111), a compound in which the substituents, although placed at the extremities of rz chain of four carbon atoms, are nevertheless situated a t the opposite ends of different benzene rings, shows no tendency to yield a diazoimide when treated with nitrous acid, this negative result indicating that the presence of one substituent in the 4- or %position with respect to the other does not in itself determine the formation of a diazo-anhydride by internal condensation, but that the orientation of the two groups in the aromatic nucleus is the more important factor.IIi. IV. v. BenxenesuZphonyI- 1 ; B-.iz~phtl~ylenediccmine (IV), which contains one substituent in the 3- or y-position with respect to the other, these two groups being situated in adjacent positions in the two rings, yields a diazoanhydride quite as readily and completely as its homo- nucleal para-isomeride (V) (Trans., 1905, 85, 929). The new peri- diazoimide (VI) is yellow and also comparable in all other respects with the isomeric para-diazoimide (VII) already described (Eoc.cit., p. 928), and as it contains its substituents in both rings of the naphthalene nucleus, it does not seem possible to construct its formula on the assumption that an intranucleal quinonoid rearrangement has6 MORGAN AND MICKLETHWAIT : THE DIAZO-DERIVATIVES OF occurred, and hence the cyclic structure (VI) adopted below is, in the present state of our knowledge, the simplest mode of representing the constitution of the compound, As, however, the properties of the para-diazoimides resemble so closely those of the peri-diazoimide, the adoption of a cyclic configuration (TI) for the latter compound leads by analogy to the acceptance of the cyclic structure (I) for the para- series in preference to the quinonoid formula (11). Accordingly the isomeric benzenesulphonyl-peyi- and -para-diazo- imides of the naphthalene series should be represented respectively by the following formulae : ---No soz c6 H, /\/\ I I I I N \/\/ -($ N = N - N-SO2*C,H, \ / /\/\ VI. \ / VII.The quinonoid formula being excluded, the colour of these diazo- imides milst now be referred to the presence in their molecules of the chromophore -N:N-, a group which is generally assumed to be present in the coloured diazoamines, diazosulphonates, diazocyanides, and azo-compounds. Thus, the acceptance of the cyclic formula for the yellow diazoimides brings these compounds into line with other coloured azo- and diazo-derivatives. On the other hand, the ortho- diazoimidee, many of which are colourless, are also formulated as containing this group, and from this point of view it seems desirable that the constitution of these substances should be reconsidered.Further evidence in support of the foregoing formula for the peri- dinzoimide has been obtained by applying the diazo-reaction to as-benxenesulphonyZ-N-metl~yZna~hthylenediccmine, a substance which readily gives rise in succession to a diazonium salt and an azo-/?-naphthol, but does not yield a diazoanhydride, thus proving that the production of the peri-diazoimide is due to the inter- action of the diazo-group with the complex NH*S02*C6H5, for when the labile hydrogen of the latter is replaced by methyl no condensation occurs. 1 : &Naphthylenediamine, when treated with nitrous acid, yields 1 : 8-diazoiminonaphthalene, C,,H,GH>N k (De Aguiar, Rer., 1874,1 : 5- AND 1 : 8-BENZENESULPHONYLNAPHTHYLENEDIAMINES. 7 7, 3 15), a red compound, which, unlike its foregoing benzenesulphonyl derivative, does not undergo fission when treated with cold concen- trated hydrochloric acid, and accordingly resembles the stable ortho- diazoimines.Hence, as regards its behnviour towards nitrous acid, pe&- or 1 : 8-naphthylenediamine occupies a position intermediate between the ortho- and para-diamines. Like the former, it yields itself a stable diazoimino-compound not decomposed by acids, the peri- derivative, however, differing from the ortho-diazoimines in being intensely coloured. The relationship of the peri-base to the para- diamines is plainly indicated by the analogous behaviour of their benzenesulphonyl derivatives, as set forth in the foregoing discussion, E: X P E RIME N TAL. Prepcwcbtion of 5 - and 8-Nit~o-a-nc~pht~?jZami~aes.The method of preparation employed, which was originally devised by Noelting, has already been dcscribed in this Journal (Meldola and Streatfeild, Trans,, 1893,83, 1054). It consists in nitrating a well- cooled solution of 100 grams of a-naphthylamine in 1000 grams of concentrated sulphuric acid with 64 grams of nitric acid (sp. gr. 1.42) mixed with 128 grams of concentrated sulphuric acid. The reaction being liable to get out of control, the solution of the base in the con- centrated sulphuric acid and the addition of the nitrating mixture must both be carried out very slowly a t low temperatures ; the pro- duct, when left overnight and poured into iced water, yields a dark brown precipitate which contains 5-nitro-a-naphthylamine sulphate.The filtrate, when neutralised with sodium carbonate, yielded crude 8-nitro-a-naphthylamine, which was purified by repeating several times the operation of dissolving the base in sulphuric acid, filtering the solution from sparingly soluble sulphate, and reprecipitating with sodium carbonate. The crude sulphate of the 5-nitro-base was dissolved in boiling water and the base set free from the filtered solution by sodium carbonate. Ultimately, the two isomerides were further purified by crystallisa- tion from petroleum, when the peri-base was obtained from the solvent boiling at 80-100' in red leaflets and scales melting at'95-97", whereas the 1 : 5-isomeride crystallised from the fraction (b.p. 100-120°) in dark red needles melting a t 114--116'. The yield of tnhe peri-base was about 5-6 per cent. of the weight of a-iiaphthylamine originally taken, and the nitration was repeated until about 30 grams of this material bad accumulated.8 MORGAN ANT, MICKLETHWAIT : THE DIAZO-DERIVATIVES OF Action of BemenesuZpl.onic CIA Zoride on the Two Nitro-a-naphth ylamincs. The nitro-base (1 gram) was dissolved in dry pyridine (10-20 c.c.), treated with 1 -5 grams of benzenesulphonic chloride, and the solution heated to boiling for some time. With the 1 : 5-base, the reaction was practically completed in three hours, but with the 1 : S-isomeride a large proportion of unaltered base was recovered, even after beating for 10-12 hours." The product was poured on to crushed ice, acidified with dilute liydrochloric acid, and the insoluble residue dissolved in aqueous sodium carbonate.The crude benzenesulphonyl derivative, when reprecipitated from the alkaline solution with dilute hydrochloric acid, was crystallised from dilute alcohol (1 : 1). Re.lzzenesuZphoia~Z-5-nit ro-a-naphtlhylamine, NO,* C,,H, *NH*SO,*C,H,, crystallised in needles and melted at 183'. 0.2008 gave 15.6 C.C. nitrogen at 19' and 753 mm. C,,H,,O,N,S requires N = 8-53 per cent. BenxenesuZp?~onyl-8-nnitro-a-naphthyZarniiae, when crystallised first from dilute and then from strong alcohol, separated in almost colour- less needles melting a t 194'. N = 8.85. 0.2128 gave 15-85 C.C.nitrogen at 19.5" and 744 mm. N=8*36. 0.1602 ,, 0.3434 CO, and 0-0539 H,O. C=58.46 ; H= 3.74. C,,H,,O,N,S requires N = 8-53 ; C = 58.53 ; H = 3.66 per cent. Reduction of the Benxenesulp?AonyZnitro-a-~p?At~~yZ~~m~nes. Five grams of the nitro-derivative were suspended in 250 C.C. of warm water and treated with 10 grams of iron and 1.5 C.C. of glacial acetic acid; the mixture was boiled for half an hour, when the reduc- tion, which took place with the same readiness for both isomerides, appeared to be complete. The mixture was rendered alkaline with sodium carbonate and filtered ; in both cases the benzenesulphonyldi- amine remained in solution and was at once precipitated with dilute acetic acid. Benzewsu@honyZ- 1 : 5-naphthyZenediacmi~ae, NH,-C,oH,-NH=SO,* UGH,, crystallised well either from alcohol or from toluene containing a small proportion of petroleum (b.p. SO-100'); from the former medium, i t separated in large aggregates of radiating, colourless, silky needles, some of the individual crystals being 1B inches long. Its melting point was 161O. * It was found that the colour of the recovered 1 : 8-base was much less intense than that of the original specimen, and that its melting point had risen to 98--100".0.1874 gave 15 C.C. nitrogcn nt, 19" and 779 mm. 0.37.00 ,, 0.2881 BaSO,. S = 10.69. N=9*44. C16H,40,N,S requires N = 9 *39 ; S = 10.73 per cent. Uenxenesulphonyl- 1 : 8-ni,tplrtTi ylenediamine crystallised less readily than its isomeride from dilute alcohol or from toluene and petroleum, and separated in pale grey needles melting at 166".0.2304 gave 19-0 C.C. nitrogen at 19' and 744 mm. N = 9.27 per cent. Action of Nitivzcs Acid on the BenxenesuZplmnnyl-1 : 5- and -I : 8- napht Jt y lenedianaines . One gram of the 1 : 5-isomeride, when suspended in 12 C.C. of glacial acetic acid and 8 C.C. of' concentrated hydrochloricacid and treated a t - 10' to -5' with 2-8 C.C. of aqueous sodium nitrite (20 per cent.), yielded a soluble diazonium chloride together with a brown, amorphous product. The latter was removed by filtration, the filtrate diluted with water, and again filtered from a small proportion of tarry matter ; the final filtrate, when treated with a large excess of aqueous sodinm acetate, remained clear and showed no indications of yielding an insoluble diazoimide.The diazotised product was shown to be still in the form of a diazonium salt by combining it with @naphthol. The red sodium derivative of the azo-naphthol, which XIS deposited almost completely from the alkaline solution, when collected and treated with acetic acid, yielded besaxe1aesu~T~on~l5-ami~aonc,tpT~tT~alene- 1-azo- P-naphthol, NH*SO,* C,H, /\/\ 9 I l l \/\/ HO* C,,H6-N, which separated from glacial acetic acid in red, felted needles and melted at 260'. Om16O0 gave 13.0 C.C. nitrogen at 19' and 755 mm. N = 9.52. C26H,i,0,N,S requires N = 9.27 per cent. The azo-compound developed an intense reddish-violet coloration witli cold concentrated sulph uric acid.10 MORGAN AND MICKLETHWAIT : THE DIAZO-DERIVATIVES OF BenxenesuZplLonyLl : 8-na~~thylenediaxoilnide, N,-N*SO,*C,H, 1 1 /\/\ I l l \/\/ Benzenesulphonyl-1 : 8-naphthylenediamine ( 1 *5 grams), suspended in 12 C.C.of glacial acetic acid and 12.0 C.C. of concentrated hydro- chloric acid, cooled to - lo", and slowly treated with 3.6 C.C. of aqueous sodium nitrite (20 per cent.),gave rise to a soluble diazonium chloride together with a small proportion of a greenish-brown, amor- phous precipitate. The filtered solution yielded a further deposit of viscid impurity on dilution, and, after filtration, was cautiously treated with dilute aqueous sodium acetate to remove last traces of resinous products. As soon as the acetate gave a slight permanent precipitate of cyclic diazoimide, the turbid solution was again filtered, and the clear, light yellow filtrate then treated with excess of concentrated acetate solution, when the diazoimide separated as a flocculent, orange- yellow precipitate, which on stirring became crystalline and lighter in colour.The deposit, which was collected and thoroughly washed successively with water, alcohol, and light petroleum, was dried in the desiccator until its weight was constant. The alcohol removed a red impurity, but otherwise the diazoimide was quite insoluble either in this solvent or in water ; when thoroughly dried, the compound, without further purification, gave the following numbers on analysis : 0.2353 gave 0.5368 CO, and 0.0754 H,O. C = 62.22 ; H= 3.56. 0.2416 ,, 0.5481 CO, ,, 0.0804 H20. C = 61.8s ; H= 3.69. 0.2486 ,, 0.5687 CO,. C = 62.39. 0.1524 ,, 17.2 C.C.nitrogen at 19' and 779 mm. N = 13-45. 0.2173 ,, 0.1673 BaSO,. S= 10.57. C,,H,,O,N,S requires C = 62.14 ; H = 3.56 ; N = 13.59 ; S = 10.35 per cent. When heated in the combustion tube, the substance decomposed energetically, evolving puffs of yellow smoke. It may be kept for an indefinite time in the dark, but is affected by light, rapidly becoming brown.* The sodium acetate filtrate from benzenesulphonyl-1 : S-naphthylene- diazoimide was added to alkaline P-naphthol, but no azo-colour was * The colour of the yellow dinzoimides assumes a paler hue, but is not entirely destroyed when the compounds are cooled to the temperature of liquid oxygen.1 : 5- AND 1 : 8-RENZENESULPHONYJ4NAPHTHYLENEDIAM1NES. 11 produced, thus showing that the conversion of the diazonium salt into the 1 : 8-diazoanhydride was complete. Pissi0.n of the peri-Diaxoimide.(1) Fission with Acids.-When suspended in 50 parts of cold glacial acetic acid, the diazoimide remained undissolved, and only passed into solution on warming on the water-bath. The deep red liquid, when poured into alkaline P-naphthol, yielded the alkali derivative of the am-compound, which was treated with glacial acetic acid in order to set free the azo-P-naphthol. The peri-diazoimide dissolved immediately in ice-cold concentrated hydrochloric acid to an almost colourless solution, which, when diluted with cold water and poured into alkaline P-naphthol, yielded the alkali azo-derivative, from which the free azo-naphthol was isolated by means of acetic acid. Another portion of the solution in hydrochloric acid after dilution with water was treated with excess of platinic chloride, when a pale yellow, crystalline diaxonium pialanzchloride was precipitated, which, when dried in the air, gave the following result on analysis : 0.2315 gave 0,0427 Pt.(C,H,*S0,*NH*C,,H,*N2),PtC16 requires Pt = 18.95 per cent. (2) Fission with Phenols.-Equal parts of the peri-diazoimide and @-naphthol were dissolved in dry pyridine and heated for two and a half hours on the water-bath. The deep red solution thus obtained was allowed to evaporate slowly, the solid residue was treated with excess of aqueous caustic soda and collected, the free azo-naphthol being then set free by glacial acetic acid. Pt = 18.44. BenxemesulphonyI-8-ccminonaphthalene- 1 -azo-p-naphthol, HO*C,,H,*N:N NH*SO,*C,H, /\/\ I l l \/\/ The azo-compound produced in the foregoing fission experiments was dissolved in benzene and precipitated from this solution by the addition of light petroleum.0.1802 gave 14.2 C.C. nitrogen a t 19.5' and 771 mm. C2,Hl9O3N:&3 requires N = 9.27 per cent. This compound, which was not obtained crystalline, melted some- what indefinitely at 1 70-180°, and developed an intense reddish-violet coloration with cold concentrated sulphuric acid. N = 9.18.12 AS-BENZENESULPHONYIJ-N-METHY Id- 1 : 8-NAPHTHY LENEDIAMINE BenzenesuZplt,on$-8 -nitro-N-rnetlTLyZ-a-na~ht~~~Zu~i?~e, N0,.G',,H,*N(C'H,)*S02*CGHF,. An alcoholic solution of 2 grams of recrystallised benzenesulphonyl- 8-nitro-a-naphthylamine and 0.3 grain of caustic soda was boiled for six hours with excess of methyl iodide (2 grams) added in small portions.The crystalline residue obtained after evaporating off the solvent was washed successively with aqueous caustic soda and water, and when crystallised repeatedly from alcohol separated in pale yellow needles melting a t 170". 0.2851 gave 2043 C.C. nitrogen at 19" and 766 mm. C,7Hl,0,N2S requires N = 8.18 per cent. The alkylation was practically quantitative ; the alkaline filtrates from the as- benzenesulphon yl- 8 4 tro-N-methy 1 -a-naph thy lami ne gave on acidifying no unmethylated nitro-compound, as-Benxenesulphony I-N-methy Z- 1 : S-napl~tlh$enedicmine was readily obtained from the foregoing nitroderivative by reducing 4 grams of this substance with 16 grams of iron, 2 C.C.of glacial acetic acid, and 200 C.C. of warm water, the heating being continued for an hour before the mixture was rendered alkaline with sodium carbonate. The alkaline filtrate from the iron oxide contained no organic base, the product being isolated from this insoluble residue by repeated extraction with alcohol. The new base did not crystallise well from this solvent, but was deposited in brownish-white, nodular crystals from its benzene solution on the addition of a small quantity of light petroleum. N = 8.45. 0.2898 gave 22.2 C.C. nitrogen at 19' and 772 mm. C,7HlG0,N,S requires N = 8-97 per cent. After repeated crystallisation, the substance melted at 161-1 62". N=8*95. as-BenxenesuZphonyZ-N-melhyl-8-uminonaphthalerne-l -ccxo-~-~aphthoI, /\/\ I l l HO* C,,H,*N:N N(CH,)* S02*C,H, \/\/ When diazotised with aqueous sodium nitrite in a mixture of con- centrated hydrochloric and acetic acids at - 10" to - 5 O , the preceding methyl base yielded a soluble diazonium salt, from the filtered solution of which aqueous sodium acetate precipitated no insoluble diazo- anhydride. The clear solution of the diazo-salt, when poured into an alkaline solution of @-naphthol, yielded an insoluble bright scarlet azo-AZO-DERIVATIVES OF 4 : 6-DIMETHYLCOOMARIN. 13 compound which crystallised readily from glacial acetic acid in trans- parent, ruby-red nodules. 0.2359 gave 18 C.C. nitrogen at 19" and 770 mm. This azo-derivative, which melted a t 215", developed an intense N=8.89. C,7H,,0,N,S requires N = 8-99 per cent. reddish-violet coloration with cold concentrated sulphuric acid. The authors' thanks are due to the Government Grant Committee of the Royal Society for a grant which has partly defrayed the expenses of this investigation. ROYAL COLLEGE OF SCIENCE, LONDON, SOUTH KENSINGTON, S. W.