Benzohydrazides, benzothiohydrazides, and benzamidrazones as sources of 1,3,4(2H)-oxadiazolenones, 1,3,4(2H)-thiadiazolenones, and 1,2,4(5H)-triazolenones

Benzohydrazides, benzothiohydrazides, and benzamidrazones have been converted to 1,3,4(2H)-oxadiazolenones, 1,3,4(2H)-thiadiazolenenones, and 1,2,4(5H)-triazolenones respectively by reaction with ethyl chloroformate, with ethyl thiolchloroformate, and with phenyl isocyanate. In some reactions, a carbamate or urea has been isolated as intermediate.