Open-chain nitrogen compounds. Part II. Preparation, characterization, and degradation of 1(3)-Aryl-3(1)-methyltriazenes; the effect of substituents on the reaction of diazonium salts with methylamine

Abstract

Treatment of the diazonium salts, X•C6H4N2+, with aqueous methylamine affords good yields of the monomethyltriazenes, X•C6H4•N=N•NHMe, when the substituent is a strongly electron-withdrawing group (X = o-, m-, and p-NO2; o-, m-, and p-CO2R; p-CN and p-COCH3). Preparation of the triazene from the p-bromobenzene diazonium salt was accompanied by formation of a pentaazadiene. Monomethyltriazenes were not obtained when diazonium salts containing other substituents (X = H, p-CH3, o-CF3, p-Cl, p-F, p-NMe2, p-OH, p-OCH3, p-Ph, p-NHCOCH3) were treated with methylamine. In these cases the products were either pentaazadiene, or 1,3-diaryltriazenes or unstable materials. The monomethyltriazenes vary considerably in stability and give rise to a number of different degradation products, which were either diaryltriazenes or 3-alkyl-1,3-diaryltriazenes or simply arylamines. 1(3)-(p-Nitrophenyl)-3(1)-methyltriazene was found to be a moderately effective methylating agent.