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 aroyl-hydrazone 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-pyraz oles 9a-c respectively. Some of these compounds showed anti-inflammatory, antibacterial or antifungal activities comparable to that of Proquazone, Ampicillin, or Clotrimazole respectively.