Facile regeneration of carbonyl compounds from semicarbazones by potassium bromate

Abstract

Oxidation of semicarbazones of benzaldehydes and acetophenones by potassium bromate (Br^V) yields the respective aldehyde or ketone in good yield at ambient temperature. The rates of these reactions are little influenced either by the change in substituents at the phenyl ring or by the polarity of the medium, suggesting that the intermediate for the reaction is probably as polar as the reactants. The reaction possibly proceeds via a preformed N-bromate ester in the slow step whose formation is, generally, less susceptible to electronic effects.