Design and Synthesis of Some Oxadiazolyl, Thiadiazolyl, Thiazolidinyl, and Thiazolyl Derivatives of 1H-Pyrazole as Anti-inflammatory Antimicrobial Agents

Abstract

Four series of 1H-pyrazole derivatives have been synthesized. The first series was prepared by cyclization of the intermediate 3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazole-4-carbaldehyde aroylhydrazone 4a—c with acetic anhydride to afford the corresponding oxadiazoline derivatives 5a—c. The other series were prepared by the cyclization of the intermediate 3-(5-bromo-2-thienyl)-1-phenyl-4-substituted thiocarbamoylhydrazonomethyl-1H-pyrazole 6a—c with acetic anhydride, ethyl bromoacetate or phenacyl bromide giving rise to 3-(5-bromo-2-thienyl)-1-phenyl-4-[3-acetyl-5-(N-substituted acetamido)-2,3-dihydro-1,3,4-thiadiazol-2-yl]-1H-pyrazoles 7a—c, 3-(5-bromo-2-thienyl)-1-phenyl-4-(3-substituted-4-oxothiazolidin-2-ylidenehydrazonomethyl)-1H-pyrazoles 8a—c, or 3-(5-bromo-2-thienyl)-1-phenyl-4-(3-substituted-4-phenyl-2,3-dihydrothiazol-2-ylidenehydrazonomethyl)-1H-pyra zoles 9a—c respectively. Some of these compounds showed antiinflammatory, antibacterial or antifungal activities comparable to that of Proquazone, Ampicillin, or Clotrimazole respectively.