Hypervalent Iodine Oxidation of N-Acylhydrazones and N-Phenylsemicarbazone: An Efficient Method for the Synthesis of Derivatives of 1,3,4-Oxadiazoles and Δ3-1,3,4-Oxadiazolines

Article abstract of DOI:10.1021/jo00064a027

The oxidation of ketone N-acylhydrazones 1 by phenyliodine(III) diacetate (PIDA) in alcohol gave 2-alkoxy-Δ³-1,3,4-oxadiazolines 4 in excellent yields, while the oxidative cyclization of aldehyde N-acylhydrazone 2 by PIDA in methanolic sodium acetate gave 2,5-disubstituted 1,3,4-oxadiazoles in good yields.The oxidation of acetone 4-phenylsemicarbazone afforded 2-(N-phenylimino)-Δ³-1,3,4-oxadiazoline in excellent yield.