Formation of 1,3,4-oxadiazolines and 1,3,4- oxadiazepines through acetylation of salicylic hydrazones.

Abstract A new series of 1,3,4-oxadiazolines and 1,3,4-oxadiazepines are prepared in a one-step reaction through cyclization of various N -benzylidene-2-hydroxybenzohydrazides. Cyclization in acetic anhydride yielded 1,3,4-oxadiazolines, while the reaction carried out in acetic anhydride–acetic acid gave 1,3,4-oxadiazepines, in some cases.