CONSTITUTlON OF THE ORTHO-DIAZOIMINES. PART IV. 1 I 'rXV 1.- Constitution of the ortho- Dirxoirnincs. Part I V.home p i c Benzenesulp hon y l-3 : 4 - t ol y lenr diazoimid es.By GILBERT T. MORGAN and GODFREY EDWARD SCUFF.IN a recent communication (T., 1913, 103, 1394) it was demon-strated that the isomerism of the two so-called a- and 8-acetyl-3 : 4-tolylenediazoimides is of a structural nature, and due to differencesin the orientation of the double linking and acetyl group in theisotriazole ring. The preparation of a similar pair of isomericbenzoyl-3 : 4-tolylenediazoimides showed, moreover, that the exist+ence of these isomerides is not dependent on the specific characterof the acyl group present. The four acylated ortho-diamines fromwhich these two pairs of isomeric diazoimides were prepared undergocondensation very readily, passing into ethenyl and benzenylanhydro-bases respectively.On this account it was difficult todiazotise these bases quantitatively.Two isomeric acylated ortho-diamines have now been prepared,which, being free from this tendency to condensation, can be con-verted without loss into their corresponding diazoimides. Theaebases, 44 enzenesulphonyl-3 : 4-tolylenediamine (formula 11) ani118 MORGAN AND SCHARFF:3-benzehesulphonyl-3 : 4-tolylenediamine (formula V), on treatmsntwith nitrous acid give rise respectively t o 4-benzenesulphonyl-3 : 4-tolylenediasoimide (formula 111; m. p. 118-119O) and 3-benzen.e-sulphon&3 : 4-tolylenediazoimide (formula VI, m. p. 150-151O). I neach case the product, which is obtained in quantitative yield,consists of one isomeride only.As regards the orientation of itssubstituents, the former of these diazoimides corresponds withZincke and Lawson's less fusible a-acetyl-3 : 4-tolylenediazoimide(AnnuZen, 1887, 240, 119), and the latter isomeride with the morefusible P-acetyl-3 : 4-tolylenediazoiniide. In the present instance itie, of interest to note that the fusibility is reversed, the &(or 3-ben-zenesulphony1)compotnd being the less fusible. The more fusiblea-(or 4-benzenesulphony1)isonieride is a labile modification, and onprolonged boiling in benzene or alcoholic solution it is transformedalmost entirely into the less fusible 8-isomeride. A similar exampleof isomeric change in this series of compounds has already beennoticed in the case of l-benzenesulphonyl-4-bromonaphthylene-2-diazo-l-imide, which, under comparable conditions, becomes con-verted into 2-benzenesulphonyl-4-bromonaphthylen~l-diazo-2-imide(T., 1910, 97, 1705).I n both instances the more fusible and moresoluble diazoimide changes into its less fusible and less solubleisomeride.I n the caqe of the acetyl-3 : 4-tolylenediazoimides prolonged boilingof either isomeride in alcoholic soltition leads to an equilibriummixture of the two compounds.The production of the isomeric benzenesulphonyl-3 : 4-tolylene-diazoimides is sumrnarised in the following diagram :C H,(111.) or-Isorneri;de(w. p. 118-119").I ACH,+TCH,(VI.) 13-Isomeride(m.p. 150-151").The parent nitro-base of the lower series of compounds is d-nitro-3-toluicline (m. p. 111--112°), and these experiments have inci-dentally afforded an opportunity of establishing the identity of thCONSTITUTION OF THE ORTHO-DIAZOIMINES. ART IV. 11 9nitr*l,ase produced from m-toluidine and diacetyl-2 : 5-tolylene-diainine with the preparation obtained from m-cresol by Stadeland Kolb (AnnuZen, 1890, 259, 224), who gave the melting pointas logo.EXPERIMENTAL.4-BenzenesuZphonyL3-nitro-p-toluidine (Formula I).Molecular proportions of 3-nitro-ptoluidine, benzenesulphonicchloride, and triethylamine dissolved in benzene were heated in areflux apparatus for two hours. The solvent was evaporated, theresidue extracted with N-sodium hydroxide, and the filtered solutionacidified with hydrochloric acid.The precipitate was purified bysuccessive crystallisations from petroleum (b. p. SO-100.) andbenzene. The substance separated either in transparent, amber-coloured prisms or in colourless, acicular prisms, both modificationsmelting a t 101-102° :0.1954 gave 0.1576 BaSO,. S= 11.07.C,3H,20,1N,S requires S = 10.96 per cent.In preparing 4-benzenesulphonyl-3-nitro-ptoluidine by the aboveprocess it was found that a residue of unchanged 3-nitro-ptoluidinewas left after extracting ths crude product with aqueous sodiumhydroxide. Accordingly, the condensation in dry toluene wasrepeated a t 140° in sealed tubes, when the reaction went to com-pletion and a good yield of the acyl derivative was obtained.Thissubstance behaved as an acid, decomposing carbonates, and yieldingyellow, soluble alkali salts.4-Benzenesulphon yZ-3 : 4-tolylenediamine (Formula 11).The foregoing nitro-compound (10 grams), suepended in warmwater (200 c.c.) acidified with 2 C.C. of glacial acetic acid, wasreduced by the gradual addition of iron filings (10 grams). Afterboiling for thirty minutes the solution was neutralised with calciumcarbonate, filtered hot, and the filtrate acidified with acetic acid. Abulky, white precipitate was obtained, which was purified by crystal-lisation from water or from benzene and petroleum. The substanceseparated from the former solvents in colourless, felted needles, andfrom the latter in sheaves of lustrous, colourless, silky needles,melting a t 146-147O :0.1240 gave 11.3 C.C.N, a t 20° and 757 mm.C,3R,,0~2S requires N = 10.69 per cent.The acylated diamine was readily soluble i n alcohol, but onlysparingly so in light petroleum; *it was amphoteric, decomposingcarbonates, and forming salts with either bases or mineral acids.N=10.43120 MORGAN AND SCHARFF:4-Benaenesulphorcyl-3 : 4-tolylenediaaoimide (Formula 111).The preceding base (1 gram), dissolved in 10 C.C. of 23-hydro-chloric acid, yielded forthwith a precipitate of the sparingly solublehydrochloride, separating in colourless leaflets. The mixture, dilutedto ten times its bulk, was treated at the ordinary temperature with6 C.C. of N-sodium nitrite, when the diazoimide separated as acurdy precipitate.As this product is practically insoluble in coldwater, the experiment was repeated quantitatively, when 1 gram ofdiamine yielded 1-02 grams of diazoimide, melting a t 115O, thecalculated amount being 1-04 grams.After two rapid crystallisations from alcohol or from petroleuin(b. p. 80-looo) the diazoimide crystallised in glistening, colourless,acicular prisms, showing cruciform twinning, and melting at118-119O. A mixture with the isomeric 3-benzenesulphonyl-3 : 4-tolylenediazoimide melted a t 105-108O :0.1374 gave 17.8 C.C. N, a t 1g3 and 767 mm.0.1322 ,, 0.1130 BaSO,. S=11*74.C,H,,O,N,S requires N= 15.38; S=ll.72 per cent.4-Benzenesul~7ionyl-3 : 4-tolylenediazoimide is much more solublethan its isomeride (formula VI), but when its solutions in alcohol,benzene, or petroleum are boiled for some time transformation intothe less soluble isomeride takes place, the product crystallising outin the long, glistening prisms characteristic of 3-benzenesulphonyl-3 : 4-tolylenediazoimide.The transformation product melted at148--149O, and its mixture with 3-benzenesulphonyl-3 : 4-tolylene-diazoimide melted at the same temperature. A sulphur estimationin the transformation product gave S = 12.30, the calculated amountfor a purely isomeric change being 11-72 per cent. This resultshows that in the present instance the transformation takes placewithout any elimination of the benzenesulphonyl group. I n the caseof the pair of naphthalenoid diazoimides already cited (T., 1910,ibid.), traces of moisture or other impurities promote hydrolysis, sothat the product of the change is a mixture of stable benzene-sulphonyldiazoimide and the corresponding diazoimine.N= 15-23,Preparation of 4-Nitro-m-toluidine.The melting point of 4-nitro-m-toluidine was given as 109O byStadel and KolE (Zoc.cit.), who prepared it from m-cresol, and as110-110*5° by Cohen and Dakin, who obtained it from aceto-m-toluidide (T., 1903, 83, 333). The latter melting point correspondedwith that obtained for the product (m. p. 111-112°) preparedfrom diacetyl-2 : 5-tslylenediamine (T., 1913, 103, 1399). I n srdeCONSTITUTION OF THE ORTHO-DIAZOI&fINES. PART IV. 121to confirm the identity of these preparations the base employedin the following experiments was obtained partly from m-cresoland partly from m-toluidine.Both preparations after repeatedcrystallisation from petroleum (b. p. S0-1OO0) melted a t 111-112°,and the mixed melting point, showed no depression.(1) Pron2 m-CresoZ.-Stadel and Kolb’s method of nitration(Zoc. c i t . ) was adopted, and the required 4-nitro-m-cresol separatedfrom 6-nitro-m-cresol by distillation in steam. The volatile nitro-compound was dissolved in alcohol, and treated with the calculatedamount of alcoholic sodium ethoxide. The precipitated scarletsodium salt, washed with ether until free from alcohol, was dissolvedin water and decomposed with silver nitrate. The dark red silver4-nitro-m-tolyloxide was washed with ether, thoroughly dried, andmixed with excess of ethyl iodide.An exothermic change occurred,which was inoderated by the a.ddition of dry ether. The mixturewas then boiled in a reflux apparatus for twelve hours, and thesilver iodide repeatedly extracted with ether. The collected filtrateswere evaporated t o remove ether, when the residue solidified t o acrystalline mass of 4-nitro-m-tolyl ethyl ether (m. p. 50-51°). Itwas found necessary to avoid the presence of alcohol in preparingthe above silver salt, as this solvent has a marked reducing actionon the metallic compound.The 4-nitro-m-tolyi ethyl ether (5 grams) was heated for twelveto eighteen hours a t 190-200° with 10 C.C. of alcohol and 10 C.C. ofaqueous ammonia (D 0.88). After evaporating to dryness, theresidue was extracted repeatedly with concentrated hydrochloricacid.The diluted filtrate was rendered ammoniacal, and the pre-cipitated 4-nitro-m-toluidine crystallised from light petroleum.(2) From m-Toluidiize.-Recrystallised aceto - m - toluidide (20grams) was dissolved i n 24 C.C. of glacial acetic acid, and treatedsuccessively with 74 C.C. of nitric acid (D 1-42} and 40 C.C. of con-centrated sulphuric acid. The solution was cooled if necessary, 80that the temperature did not exceed 30°, and after several hourswas poured on t o ice; the nitrated product, which separated as ayellow, crystalline precipitate, was recrystallised f lorn alcohol. Thepurified material suspended in 20 parts of boiling water acidifiedwith acetic acid, was reduced with iron filings. After boiling forthirty minutes and then adding calcium carbonate, the filtrate,acidified with acetic acid, was concentrated to a small bulk, treatedwith acetic anhydride, and the evaporation completed.The crudediacetyl-2 : 5-tolylenediamine was crystallised from hot water, andnitrated in glacial acetic acid by the successive addition of half itsweight of nitric acid (D 1-42> and the same a.mount of concentratedsulphuric acid. Hydrolysis of the nitrated product with alcoho122 MORGAN AND SCHARFF:and concentrated hydrochloric acid in equal volumes furnished4-nitro-2 : 5-tolylenediamine (m. p. 173O). The conversion of thisdiamine into 4-nitro-m-toluidine was carried out as in the previouscommunication (Zoc. cit.), but in such a manner as t o obtain acomplete diazotisation to the lrionodiazonium salt.The diamine(3 grams), suspended in 10 C.C. of glacial acetic acid saturated withhydrogen chloride, was treated with dry sodium nitrite in slightexcess. The orange-yellow hydrochloride changed in colour to olive-green, and then to light brown, the diazonium chloride being almostcompletely dissolved. Dry ether was now added, and the precipi-tated diazonium salt, which is very sensitive t o light, was rapidlycollected, washed with ether, suspended in absolute alcohol, and themixture boiled so long as the odour of acetaldehyde was noticeable.After evaporating nearly t o dryness, the residue was renderedammoniacd, and the precipitated base crystallised from petroleum(b.p. 80-looo), being thus obtained in orangeyellow spicules(m. p. 111-112°). The yield was 60-70 per cent. on the weightof 4-nitro-2 : 5-tolylenediamine.3-Benzen eszclph o n!yl-4-n,itro-m-t oluidine (Formula IT).4-Nitro-m-toluidine dissolved in dry toluene was heated f o r fivehours a t 130-140° in sealed tubes with rather more than thecalculated quantities of benzenesulphonyl chloride and triethyl-amine. The product was extracted with alcohol, the volatilesolvents evaporated, and the residue warmad with axcess ofN-sodium hydroxide. The alkaline filtrate acidified with hydro-chloric acid gave a precipitate of 3-benzenesulphonyl-4-nitro-m-toluidine, which was crystallised from benzene, and separated indog-toothed prisms melting at 137-138O :W1533 gave 0.1240 BaSO,.C,,H,,O,N,S requires S = 10.96 per cent.This benzenesulphonyl derivative dissolved readily in alcohol,and was sparingly soluble in petroleum (b.p. 50-100°), crystal-lising therefrom in fern-like aggregates of transparent, yellowprisms.S= 11.11.3-Benzenesulphonyl-3 : 4tolylenediarnine (Pormula V).The preceding nitro-compound was reduced like its isomeride, andafter removing iron oxide the product separated from the acidifiedfiltrate in colourless, felted needles. Crystallisation from benzeneor petroleum (b. p. 80-looo) gave silky, colourless needles, meltingat 134-135OCONSTITUTION OF THE ORTHO-DIAZOIMINES. PART IV. 1230-0963 gave 9.5 C.C. N, a t 16O and 748 mm.This acylated diamine is amphoteric, forming salts with eitherbases o r acids. The acid salts serve t o separate it from unchanged3-benzer~esulphonyl-4-nitro-m-toluidine (m.p. 137--138O), which isless readily reduced than its isomeride (m. p. 101-102°).N=11*40.C,3Hl,02NzS requires N= 10.69 per cent.3-BenzenesuZphonyZ-3 : 4-toZyZenediazoimide (Formula VI).3-Benzenesulphonyl-3 : 4-tolylenediamine (1 gram) was added to10 C.C. of N-hydrochloric acid, when the sparingly soluble hydro-chloride separated in colourless, nacreous leaflets. The solutiondiluted ten-fold was treated a t the ordinary temperature withA7-sodium nitrite, when the diazoimide separated immediately as acurdy precipitate, the yield being quantitative. The dried product(m. p. 147O) was crystallised from alcohol, in which it is much lesssoluble than its isomeride ; it separated in lustrous, colourless prismsoften more than 1 cm. in length, and melted a t 150-151O:0.1346 gave 18 C.C. N, at 15O and 758 mm. N= 15.71.0-0983 ,, 0.0862 BaSO,. S=12*04.C,3H,10,N,S requires N= 15.38; S.= 11.72 per cent.3-Benzenesulphonyl - 3 : 4 - tolylenediazoimide crystallised frombenzene in lustrous, tabular prisms; its mixed melting point withthe isomeric 4 - benzenesulphonyl - 3 : 4 - tolylenediazoimide wasWhen warmed to 80°, both the isomeric benzenesulphonyl-3 : 4-tolylenediazoimides manifest an odour resembling that of liquorice.I n this respect they resemble the isomeric acetyl-3: 4-tolylenediazo.imides.105-108°.The authors desire to express their thanks to the b e a r c h GrmtCommittee of the Royal Society for a grant which has partlydefrayed the expenses of this investigation.ROYAL COLLEGE OF SCIENCE FOR IRELAND,DUBLIN