Synthesis and Antimicrobial Activity of a New Class of Benzazolyl Pyrazoles

A new class of benzazolyl pyrazoles were prepared from the simple substrates benzoxazol‐2‐thiol, benzothiazol‐2‐thiol, 1H‐benzimidazol‐2‐thiol and cinnamoyl chloride and tested for antimicrobial activity. The compounds 2‐(benzothiazol‐2‐ylthio)‐1‐(3‐(benzothiazol‐2‐ylthio)‐5‐phenyl‐1H‐pyrazol‐1‐yl)ethanone and 2‐(benzothiazol‐2‐ylamino)‐1‐(3‐(benzothiazol‐2‐ylthio)‐5‐phenyl‐1H‐pyrazol‐1‐yl)ethanone showed pronounced antibacterial activity against Klebsiella pneumoniae whereas 2‐(1H‐benzimidazol‐2‐ylthio)‐1‐(3‐(1H‐benzimidazol‐2‐ylthio)‐5‐phenyl‐1H‐pyrazol‐1‐yl)ethanone and 2‐(1H‐benzimidazol‐2‐ylamino)‐1‐(3‐(1H‐benzimidazol‐2‐ylthio)‐5‐phenyl‐1H‐pyrazol‐1‐yl) ethanone displayed excellent antifungal activity against Penicillium chrysogenum.