Hydroxamic acids. II. The acetylation of O-alkylhydroxamic acids

Abstract

O-Alkylhydroxamic acids are readily acetylated, in high yield, under mild conditions. Aliphatic O-alkylhydroxamic acids yield only one product, shown to be the N-acetyl derivative. O-Alkylarylhydroxamic acids form both the O- and N- acetyl isomers; the ratio of these isomers depends on electronic and steric effects. Ultraviolet spectral data indicate that the salts of O-alkylarylhydroxamic acids exist predominantly in the hydroximic acid form; however, it is not possible to decide which is the acidic proton of the hydroxamic acid system. The nature of the cation in the salts of O-alkylhydroxamic acids is important in determining the site of acetylation.