Oxidation of 4-Alkyl-1-hydroxyimino-2,4,6-tri-<i>t</i>-butyl-2,5-cyclohexadienes : Formation of 4-Alkyl-2,6-di-<i>t</i>-butylnitrobenzenes <i>via</i> Iminoxyl Radical

Abstract

Abstract Reactions of 4-alkyl-1-hydroxyimino-2,4,6-tri-t-butyl-2,5-cyclohexadienes (1) with silver(I) oxide afforded 4-alkyl-2,6-di-t-butylnitrobenzenes (2) mainly, which were found to be formed via an iminoxyl radical on the base of the ESR spectra and by-products, 4-alkyl-1-t-butoxyimino-2,4,6-tri-t-butyl-2,5-cyclohexadienes (3). This reaction is a novel oxidative decomposition of iminoxyl radical and provides a practical preparative method for the nitrobenzenes (2). Oxidation of 1 with other reagents (nickel peroxide and m-chloroperbenzoic acid) and oxidation of 6-alkyl-1-hydroxyimino-2,4,6-tri-t-butyl-2,4-cyclohexadienes (5) have also been described.