3- Nitro-l,2-dimethylbenzene

A mixture of 300 g. (2.0 moles) of 3-nitro-l,2-dimethylbenzene (p. 222) and Raney nickel catalyst [Org. Syntheses, 21, 15 (1940)] is placed in a 1-1. bomb under a hydrogen pressure of 1500 lb. The mixture is a tated and heated gradually to 140-145°. The reaction is exothermic, and the temperature may go to about 170° near the start. Hydrogen pressure is maintained in the range 13(X)-1500 lb. until no more is being absorbed. The product is washed out of the bomb with ether, the catalyst is removed by filtration, and the water formed in the reaction is separated. The ethereal solution is dried and distilled to give a quantitative yield (215 g.) of the amine boiling at 114°/19 mm. 

A mixture of 100 g. of concentrated sulfuric acid and 50 g. of concentrated nitric acid is added dropwise with vigorous stirring to 50 g, (0.47 mole) of o-xylene cooled to —10° to 0°. The reaction mixture is poured into water, and the precipitated organic matter is separated and washed with dilute aqueous sodium hydroxide solution. The product is distilled from a Claisen flask, and the fraction boiling at 115-130°/15 mm. is collected and redistilled through a 100-cm. Fenske column to give 61 g. (86%) of 3-nitro-l,2-dimethylbenzene boiling at 127-130°/18 mm. The residue from either of the above distillations should not be heated more than necessary, since it may decompose explosively. 

Dinitro-l, 2 dimethylbenzene, ndls (from ale), mp 56—60° 89—90° obtd with other products on nitrating o-xylene or 3 nitro-o-xylene with coned nitric acid (Ref 1, p369 Ref 2, pl8l)... 

Oinitro l, 2 dimethylbenzene, ndls (from benz or acet acid), mp 116-18° si sol in hot w, cold ale petr eth mod sol in other org solvs prepd by nitrating 4 nitro deriv with mixed acid on a water bath for 10 mins and by other methods (Ref 1, p369 Ref 2. pl81 Ref 4, p82 3) a,orDinitro l, 2-dime thy Ihenzene, (0 N)gHC.CgH4.CHg yel prisms (from petr... 

Azido-3-nitro-l, 3-dime thy Ihenzene, wh ndls (from ale), mp 66° sol in common otg solvs was obtd by reaction of NH3 on the diazoperbromide of 5-nitro-4-amino-l,3-dimethylbenzene by heating under vacuum at 130°, the 4,5-Dinittoso-l,3-dimethyl-benzene deriv is formed (Ref 1, p381 Ref 3) 4-Azido-6-nitro-l,3-dimethylbenzene, ndls (from dil ale), mp 75° readily sol in ale vol in steam was obtd from the 6-nitro-4-amino deriv (Ref 1, p382 Ref 2)... 

Azido-3,5-dinitro-l, 4-dime thylbenzene, pltlts (from dil ale), mp 71-73° mod sol in benz acet ac si sol in ale v si sol in benzine prepd from 3,5 dinitro-p-xylol-diazonium-2-perbromide thru reaction with aq NH3 on heating to 105—30°, it forms 5,6-Dinittoso-2-nitro-l,4-dimethylbenzene(qv). 

Nitro-l,4-dimethylbenzene 96, by heating with excess chlorosulfonic acid at 100 °C, is claimed to yield a mixture of 3-nitro-2,5-dimethylbenzenesulfonyl chloride 97 and 4-nitro-2,5-dimethylbenzenesulfonyl chloride 98 (Equation 31). The former contains the sulfonyl moiety o- to the methyl and m- to die nitro group and is the major product in this chlorosulfonation. 

Azido-2,5 (or 5,6)-dinitTO-l, 3-dimethyl-benzene, wh pltlts (from ale), becoming yel in the light, mp 82° mod sol in ale formed by nitrating 4-azido-5-nitro-l,3-dimethyl-benzene with nitric acid (d 1.51) on heating to 110°, it forms 5,6-dinittoso-2(or 4)-nitro-1,3-dimethylbenzene (qv). Its expl props are not repotted (Refs 1 3)... 

TrinitTO-l, 3-dime thylbenzene, prisms (from ale), d 1.494 at 19° v si sol in ale can be prepd by nitrating 5-nitro-l,3-dimethyl-benzene, 4,5-dinitro-l,3-dimethylbenzene or 4-iodo-5-nitro-1,3-dimethylbenzene with mixed acid (Ref 2)... 

Heating 4-nitro-l,3-dimethylbenzene 94 with chlorosulfonic acid (two equivalents) yields the expected 5-nitro-2,4-dimethylbenzenesulfonyl chloride 95 in which sulfonation has occurred o/p with respect to the electron-donating methyl groups (Equation 30). ... 

In l,l,l,3,3,3-hexafluoropropan-2-ol, the reaction of l,4-dimethoxy-2,3-dimethylbenzene with a deficit of nitrogen dioxide gives a high concentration of the aromatic cation-radical, which lives long enough and can be detected spectroscopically. In the presence of excessive amounts of N02, this cation-radical decays rapidly giving the 5-nitro derivative of the starting compound (Eberson etal. 1996). 

Nitro-2,4-diamino-l, 3-dim ethylbenzene, or-yel nds (from w), mp 151-52° readily sol in ale diffc sol in w was prepd by reduction of 4,6-dinitro-2-amino-m-xylene with Amm hydrosulfide (Ref 1) 2-Nitro-4,6-diamino-l,3-dimethylbenzene, ruby-red prisms (from ale or boiling w), mp 212-13° sol in ale mod sol in boiling w ... 

Conversion of Phenols to Amines. Aniline and some diphenylamine are formed when phenol and NHs solution are heated under pressure in the presence of FeCh, Al(OH)s, or Fe(OH)j. When NH and phenol or ortho-or para-cresols are reacted in the vapor phase over an AljO catalyst, yields of up to 88 per cent of the corresponding amines are obtained. However, these amines are customarily obtained by reducing the parent nitro compound, except in cases where it is difficult to obtain the required nitro isomer. For example, it is considered that the amination of symr xylenol is the best method of preparing sym-xylidine (l-amino-3,5-di-methylbenzene). When sym-xylenol is heated under pressure to 320 C with ammonium chloride, about equal amounts of sj/m-xylidine and sym-dixylylamine (5-imino-bis-l,3-dimethylbenzene) are formed. The ortho-and para-nitrophenols and nitrocresols can be aminat more readily. 2-Nitro-p-cresol [OH(l), N02(2), CHj(4)] and o-nitrophenol have been aminated in aqueous ammonia containing ammonium salts of weak acids to inhibit decomposition. Phosphoric, boric, carbonic, and formic acids were used. In one case it is claimed that 55-65 per cent yields of 2-nitro-p-toluidine (MNPT of commerce) were obtained when 2-nitro-p-cresol, 28 per cent aqueous NHj, and monoammonium phosphate, 1 11.5 0.2 molar ratio, were heated under pressure for 10 hr at 140-150°C and then 5 hr at about 160 C. Earlier workers, employing somewhat similar conditions, claimed excellent yields of MNPT when 1 mole of ammonium formate was used per mole of 2-nitro-p-cresol. ... 

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