A Novel Ring-opening Reaction of (Z)-2-Methyl-4-arylmethylene-5(4H)-oxazolone Derivatives with Acylhydrazines

Abstract

The ring-opening mode of the title oxazolones with acylhydrazines was investigated from both synthetic and mechanistic points of view. It was found that the novel ring-opening reaction proceeds to give 1,3,4-triazole-substituted (Z)-α-dehydroamino acids in high yields, irrespective of substituents and solvents examined. MM2 and PM5 calculations strongly suggested that the triazole ring is constructed via the preferential nucleophilic addition of the hydrazino nitrogen to the C-N double bond in the oxazolone ring.