The chemistry of nitro-compounds. Part II. The scope and mechanism of the base-catalysed transformations of someNN-disubstituted o-nitrobenzamides

Abstract

In reactions explicable by the intermediate formation of 2-cyanoquinazolone N-oxides (2), hot ethanolic sodium ethoxide converts the N-cyanomethyl-o-nitrobenzamides (1a–c) in high yield into the N-hydroxyquinazolinediones (3a–c). In contrast, treatment of the N-benzoylmethyl-amide (6a) or the N-ethoxycarbonylmethyl-amide (6b) with ethanolic sodium ethoxide affords the indazolone (13a). The indazolones (13a and b) are formed under similar conditions from the N-α-cyanoethyl-amides (8a and b). On the other hand, hot aqueous ethanolic sodium carbonate converts the amide (8a) into a mixture of the indazolone (13a) and NN′-diphenylazobenzene-2,2′-di-carboxamide (15a); similar treatment of the amide (8b) affords the corresponding azoxybenzene derivative (16b) and benzaldehyde 2-carboxyphenylhydrazone (20). Mechanisms for the base-catalysed transformations of the amides (6a and b) and (8a and b) are discussed.