SYNTHESIS OF SOME NITRO-DERIVATIVES OF TOLUENE. 11 37 CXXVIIL-The Synthesis of some Nztro-derivatives of Toluene. By OSCAR LISLE BRADY and PERCY NOEL WILLIAMS. IN the course of an investigation it was found nemsary tol pre-pa(re a considerable quant<ity of pure 3 4-dinitrolt,oluene. This compound is formed with the 2:3- and 2:5-ismerides by the nit'ratioln of m-nit8roto;luelne and can be readily selparaiteld from the mixtare by freelzing (Beilstelin and Kuhlberg Annalen 1870 155, 25; Haaiuswrmann and Grelll Ber. 1894 27 2209; Holleman and Sirks Prolc. R. A7cad. Wetensch. Amsterdam 1906 9 280). This melthod is satisf aatory althoagh the yieilds are not lasga. Eaeusser-mann and Grelll ( h c . c i t . ) mentlion the preparation from 3-nitro-p-toluidinel by the Sandrnelyer rea,dion but do not give det'ails.As a tfrial of Ha,eusselrmann and Gredl's melthod did not give golod remlts and as m-nitrotoluene was unobtainable ab the time and it4 preparation o a a labolratory scale was very tedious other melthods of prelparation of 3 4-dinitrotdueme weire considered. The premnt p a p r deta'ls with one of thew methods. The starting material was o4duidine and the reactions involved may be summarisad M follolws : Me Me The nit?ration od ol-t801uidine to 4-nit8ro-o-t~olluidine desaribsld by Noelltling and Colllin (Ber. 1884 17 265) but by a, moldificatJon of t'heir prwelss the seipasation of t,he isomerio nitrm t'oluidines formed has been grelatly simplifield. The yiejlds obt'ained to the stage of the dinitroitloluidines were satisfasotmy but t h 1138 BRADY AND WILLIAMS THE SYNTHESIS OF remolva.1 od tlhe amincFgroap f r m these1 cojmpounds did not prove as easy as expearielnce witch similas compo'unds ha.d led the aut,hors to expect and the yield of 3 4-dinitrot.oluenei wa,s' disappoint-ing.On t,he ofbher ha,nd the oxidation of the amino!-group in the dinit,ro!-tolluidimls tlol the1 nitroigroup by mea<ns of Caro:s acid proceeds very smo801t;hly and prolvidels a oonveinisnt meitho,d of synt,he&s of 2 3 4-and 2 4 5-ttrinit,rot.olue:ne8s ivhic'n hit,he,rto ha've beeln obt,ained only by 'che nit,ra.t'ion of m-nit~roltlduelne a.nd sepasatioln of the t,wcu isommerides by fra&iolna,l crystmallisatdon (Wepp An(na+len 1882 21 5, 366) or by nitratioin off the rare 2 3- and 2 5-dinit'rotoluenes (Will, Bey.1914 47 704). E X P E R I M E N TAL. 4-Nitroux;ceto-o-toZ~~~~~de .-Onel hundred grams of o-hluidins were dissolved in 1087 O.C. ojf sulphuric acid (D 1-8) care being taken Lo avoid rise of temperature. The mixture was cooled bellow Oo in a freezing mixture and al mixture off 163 0.0. of sulphuric? acid (D 1.8) and 50.8 O.C. of nitria acid (D 1.42) coioleid to! Oo slolwly run in so that the bmperahure did not risei above Oo. When all the acid had belen added the mixture was allowed to1 remain for one hour. At this stage Noelting and Colllin (loc. cit.) neutralised all the1 acid with sodium hydroxide. A morel economical methold which avolids a great increase in the bulk od the liquid and the, formation oaf tarry products consists in adding to! the1 nitration mixture1 onehalf its bulk of watelr with thorough cololiiig and stirring.On keeping the sulphatel of 4-nitro-o~toluidine separated, and was removed by filtration and washeld with alcohol. The yield of sulpha,tte was about 60 per cent$. of the theoretical. The 6-nitro-o-toluidine formed during the nitration (Gram and Lawson T., 1891 68 1014 say 20 per cent.) remaineld in the filtrate. The sulphate was ground in a morhar with a slight excelss of 10 per cent. sodium hydroxidei and the free1 base collecteld wa,shed thoroughly with water dried a8nd acetylated with acetia anhydride. Nitration of 4-Nitro~cetol-o.toluidi~e.-A solntlion of 20 grams oif 4-nitroaw~tol-ol-toIuidide in 60 C.O. of concenl-rated sulphuria acid was added slowly with stirring tot EQ C .C . of nitric acid (D 1.5) cooled in ice. When d l the solution had been added the mixture was allowed to! remain in ice for thirty minutes and then poured into 4 litres of ice-water. The solid separating was collected at onw and thoroiughly washeld by grinding three1 or four times in a, mortas with watelr and filtering. A 70 to! 80 per aent. yielld of the mixed dinit rolscet o - o 4 oluidides was obtained . Sepuaatioa of the Dinitro-oi-tolu~~~es.-Fifty grams of the mix SOME NITRO-DERIVATIVES OF TOLUENE. 1139 turel of dinitrolamtol-o-hluidides were hydrolysed by heating for four o r five hours on the! water-bath with a mixture of 200 C.O. of oonceintratecl sulphuric acid and 400 C.O. of water. On coolling t.he mixture[ filtering and washing the precipitate first with 50 per cent.suiphuric acid and then with water a 45 pelr cent. yield of a substance mslting at 1 2 2 O was ofbtaineld. On diluting the filtrate, a 25 per cent. yielld of a ma(teria;l melting at 150-170° was p r e cipitated. The1 compound melting a t 1 2 2 O was recrystalliseld several times from alcohol1 until the product was of constant melting point, and oriented by conversion into 2 3 4-trinitrotoluene (see belolw). 3 4-Dinitro-o-tolluidine cry stallism in lustrous yellowish-brown needleis mellting at 131-131.5" (Found N = 21.5. C7H70,N, requires N=21-3 per cent.). The substance1 mellting a t 150-170° was recrystallised twice from alcohol and orienteld by conversion into 2 4 5-trinitrotoluene (see below). 4 5-Dinitro-o~toluidine orystallises in yellow needles melt-ing a t 191-191.5° (Found N=21*6.C7H70,N requires N=21.3 peir sent.). Prepration of 3 4-DinitrotoZzcene.-For this purpose it is not necessary to1 setparate! tho mixture of dinitro-o+duidine as bolth give 3 4-dinitrotoluene on removal of the aminobgroup. Nine. grams of the mixture welro dried and dissolveid in a mixture of 180 O.C. of freshly distilled absolute alcohol and 45 O.C. of faming sulphuric acid (containing 20 per ceat. of sulphur trioxide). The, solution was heated on the water-bath and 27 grams of finely powdered dry sodium nitrite were added in small portions with vigorous shaking. When all the nitrite had beea added the mix-ture was heated for five minute& oooled and diluted with water.The oily solid whioh separated was crystallised first from hot nitrio acid (D 1.4) to destroy tarry matter and then from alcohol with tohe additioa of animal charcoal when pure 3 4-dinitrotoluens was obtained. The yield was not good 2 grams only being obtained from 9 grams of the mixture of dinitrotoluidinea. Prepamtiom of 2 4 5-Trz.nitroto~luene.-Toi Carol's a d prepared from 10 g r m s of ammonium persulphatei and 7 C.O. of conceln-trated sulphuria acid poured on 20 grams of crusheld icel a solution od 2 grams of 4 :5-dinitro o tduidine (m. p. 191O) in 10 C.C. of 80 per cent. sulphuric acid was added. A clear solution was obtained which on keeping overnight deposited dinitronitrosol-toluene!; it was then diluted with water and the precipitlateld nitroaoccompound added to ten times it6 weight of nitrio acid (D 1.5) and warmed uiitil reld fumes weire not longeir evolved.On cooling and diluting the1 solution a crystalline precipitlate of 2 4 5-trinitrotoluene was obtained whioh after onel recrystallisa 1140 FERRISS AND TCTRNER: tion frolm ahholl wa8s pure. The yield was about 80 per cent. of the theoretical. Pre,paItim of 2 3 4Trinitrcrtolwen,e.-A sollution of 3 4-dinitro-o-t'csluidinel in 80 per cent. sulphurio acid was added to Ca,ro's a,cid a's acbroive; in this case holweiver the amina was pre&pit&ed by t,he dilution oif t,he sulphurio acid so the mixture1 waa tra'nsfermd to a stoppe#re,d bottllei and leift fo'r folur days wit<h freiquelnt shaking. At the end of tha.t time thei precipit'atle was collectreld and treatsd with nitric a.cid as in the previous cam when 2 3 4-t;rinit,ro~t801uene was olbt8a,ineid in goold yield. The 'authors wish ta express their thanks to the Director of RESEARCH DEPARTMENT, ROYAL ARSENAC, ArtJllelry for permission t,oi publish t'his work. WOOLWICH. [Received August 27th 1920.