A Facile and Expeditious One-Pot Synthesis of α-Keto-1,3,4-oxadiazoles

An efficient and high-yielding protocol for the preparation of α-keto-1,3,4-oxadiazoles has been developed. Formation of α-keto-1,3,4-oxadiazoles involves the 2-iodoxybenzoic acid/tetraethylammonium bromide mediated oxidative cyclization of hydrazide-hydrazones generated in situ from the reaction of aryl glyoxal and hydrazides. This one-pot protocol is reasonably general for the preparation of α-keto-1,3,4-oxadiazoles under mild conditions in short reaction times.