Synthesis of a number of new 4-methylcarbosteryl-derived oxadiazole compounds expected biological activity

Abstract

4-Methyl-2-hydroxy quioline (carbostyril) (8) was prepared via cyclization of
acetoacetanilide in presence of concentrated sulfuric acid. The ester (9) was
synthesized from the reaction of (8) with ethyl bromo acetate
The hydrizide (10) was prepared from the reaction of ester (9) with hydrazine
hydrate. 1- Formal hydrazine (11) was prepared from the reaction of hydrized with
formic acid 98%. Cyclization of (11) with P2o5
give 1, 3, 4-substituted oxadiazole (12).
The hydrazide (10) was used also for the preparation of thiosemicarbazide derivatives
(13-15) , some substituted 1,3,4-oxadiazole (16-18)synthesized from cyclization of
thiosemicarbazides using mercuric oxide, the hydrazide was used also in the preparation of substituted 1,3,4- oxadiazole (19-24) through its reaction with various
carboxylic and in the presence of phosphoric acid. Also oxadiazole-5- one compound
(25) was synthesized from the reaction of hydrized with phosgene dissolved in
toluene. The hydrazide (10) was reacted with carbon disulfide in alcoholic base
medium to produce the 1,3,4- oxadiazole- 5- thiole(26) and 1,3,4-oxadiazole -5-
methylthio (27 ) were synthesized from the reaction of compound (26 ) with methyl
iodide in presence of sodium acetate. To complete the plan of study, 2, 5-disbstituted
1, 3, 4-oxadiazole (28) were synthesized from the reaction of ester (9) with hydrazide
(10) in the presence of phosphoric acid.