Alum (KAl(SO4)2 • 12H2O):: An efficient and inexpensive catalyst for the one-pot synthesis of 1,3,4-oxadiazoles under solvent-free conditions

Alum (KAl(SO4)(2) center dot 12H(2)O) catalyzed the efficient synthesis of mono- and disubstituted 1,3,4-oxadiazoles by the condensation of acyl hydrazides with orthoesters under solvent-free conditions at 100 degrees C. This methodology offers significant improvements for the synthesis of oxadiazoles with regard to the yield of products, simplicity in operation, inexpensive reagents, and green aspects by avoiding toxic catalysts and solvents.