New Synthesis of 2-Oxoalkanamide Oximes

Reactions of α-halocarboxylic acid amides with 3 equiv of hydroxylamine hydrochloride in the presence of bases involves formation of products of nucleophilic substitution of the halogen atom and their subsequent oxidation to the corresponding oximes. This one-pot transformation can be accomplished in various aprotic solvents or ethanol at 80°C. Dimethyl sulfoxide as solvent ensures the highest selectivity for the oxidation products. The yields of N-substituted 2-(hydroxyimino)carboxylic acid amides range from 22 to 92%.