120 Scientific Proceedings, Royal Duhlin Society. 



The action of nitrogen peroxide in the vapour phase on ethyl-o-tolylurethane 

 resulted in the formation of a compound which, when decomposed by hydrochloric 

 acid, gave 4-nitro-2-niethyl-phenylamine,' and was therefore 4-nitro-2-methyl- 

 phenylurethane. 



In addition to the 4-nitro derivative, a small quantity of oxalic acid was isolated. 

 Other than the formation of a very small amount of oxalic acid, nitrogen peroxide 

 had very little action on the ure thane in solution. A similar inactivity was 

 observed in the behaviour of nitrous fumes towards solutions of the urethane in 

 acetic acid or carbon tetrachloride. 



Concentrated nitric acid (sp. g. 1"4) had very little action on the urethane, but 

 the fuming acid (sp. g. 1'5) reacted readily to form a compound melting at 

 159°-160''C., from which by decomposition with hydrochloric acid 4'6-dinitro- 

 2-methyl-phenylamine was obtained. Moreover, as the substance was formed by 

 the nitration of both 4-nitro- and 6-nitro-2-methyl-phenylurethane, it must have 

 been 4'6-dinitro-2-methyl-phenylurethane. The same dinitro derivative also 

 resulted from the prolonged action in the cold of one, two, three, four, or six 

 molecular proportions of fuming nitric acid with solutions of the urethane in 

 carbon tetrachloride, as well as by the action of excess of fuming nitric acid on a 

 solution of the urethane in glacial acetic acid. 



Apparently the nature of the solvent influences the reaction. Under similar 

 conditions of temperature and concentration, nitration takes place much more 

 easily in carbon tetrachloride than it does in glacial acetic acid solution. 



For the purpose of establishing the constitutions of the substances obtained by 

 nitration it was necessary to synthesise some nitro-o-tolyluretbanes. 5-nitro- 

 2-methyl-phenylurethane has been prepared by Vittenet [Bull. Soc. Chim. (3), 

 xxi (1899), p. 591] by the action of alcohol on the nitro-methyl-phenyl-carbimide 

 produced by the interaction of phoFgene and 5-nitro-2-niethyl-pheny]amine ; and 

 by Schiff and Vanni [Liebig's Ann. d. Chem., cclxviii (1891), p. 323] by the 

 condensation of ethyl chloroformate with 5-nitro-2-methyl-phenylamine. Vittenet 

 gives the melting point as 129^ C, and Schiff and Vanni as 137"^ 0. ; our preparation 

 melted at 137° 0. It was converted by fuming nitric acid into a crystalline 

 dinitro-compound, which melted with decomposition at 193° 0. 



In a similar manner we obtained 4-nitro-2-methyl-phenylurethane from the 

 corresponding amine. According to Vittenet [Bull. Soc. Chim. (3), xxi (1889), 

 p. 591], who obtained the substance by the action of alcohol on nitro-methyl- 

 phenyl-carbimide, the compound melts at 127° C. Our preparation, consisting of 

 almost colourless prisms, melted at 135° C, and was identical with the product 

 resulting from the direct action of nitrogen peroxide on ethyl-o-tolylurethane. 



The constitution of the compound obtained by the action of fuming nitric acid 

 on ethyl-o-tolylurethane was established in the following manner : — 



6-Nitro-2-methyl-phenylamine, on condensation with ethyl chloroformate, gave 

 6-nitro-2-methyl-phenylurethane. The latter compound was converted by the 

 action of fuming nitric acid into a substance identical with the nitration product 



' According to the usual method of nomenclature — 

 4-Nitro-2-methyl-phenylaniine is known as 5-nitro-o-toluidine. 

 5-Nitro-2-niethyl-jihenj'lamine is known as 4-nitro-o-toluidine. 

 6-Nitro-2-niethyl-pheny!aniine is known as 3-nitro-o-toluidine. 

 4'6-Diiiitro-2-methyl-phenylamine is known as 3'5-dinitro-o-toluidine. 



The nomenclature adopted in this paper shows the relation of these substances to the 

 corresponding methanes. 



