Condition-Controlled -Acylation and N-O Bond Reduction of Hydroximic Acids with Thioacetic Acid.

Condition-dependent transformations between hydroximic acids and thioacetic acid were achieved. Using NHHCO in the ethanol solvent, efficient N-O bond cleavage of hydroxamic acids occurred to afford primary amides with high functional group compatibility. The reaction was switched to -acylation when NEt and HO were used as the base and solvent, respectively. These facile transformations could be scaled up to the gram level smoothly. Preliminary mechanistic studies suggested that the N-O bond cleavage involves a cascade process of acylation/reduction.