SYNTHESIS OF HETEROCYCLIC-COMPOUNDS FROM DELTA-UNSATURATED 1,3-DIKETO-ESTERS

Diketo-esters (1) have been synthesised and converted to the correspon ding pyrazole (2), isoxazole (8) and 4-pyrone (10)derivatives. Fusion of 2 with hydrazine hydrate give the corresponding acid hydrazides (3) . Reaction of 3 with the appropriate isothiocyanate yield the disubsti tuted thiosemicarbazides (4) which are cyclized into thiotriazoles (5) , thiadiazoles (6) and oxadiazoles (7). Condensation of 3 with aromati c aldehydes yield the corresponding arylidenes (11) which are cyclized to dihydro-oxadiazole (12) and oxadiazole (13) derivatives. The Manni ch bases (15) have also been prepared from the oxadiazole-2-thione (14 ).