A New Approach for the Synthesis and Biological Activities of Novel Thiazolyl‐Pyrazole Derivatives

Abstract

AbstractAccording to the encouraging biological activity and low cytotoxicity profile of thiazolyl‐pyrazole hybrid, many researchers are making efforts in this research area. 2‐(2‐(5‐Acetyl‐4‐methylthiazol‐2‐yl)hydrazono)acenaphthylen‐1(2H)‐one (3) was synthesized by the reaction of acenaphthenequinone‐thiosemicarbazone (1) with 3‐chloroacetylacetone (2) and utilized as a precursor for the production of various thiazolyl‐pyrazole compounds. The reaction of 3 with DMF‐DMA followed by treating the produced enaminone 4 with hydrazines furnished the corresponding thiazolyl‐pyrazoles 5 a–c. In addition, 1,3‐dipolar cycloaddition of enaminone 4 with α‐ketohydrazonyl chlorides 6 through a regioselective manner gave thiazolyl‐pyrazoles 7 a–c. The reaction of 3 with arylhydrazines yielded the corresponding hydrazones 8 a–c, which were subjected to Vilsmeier formylation reaction and furnished the thiazolyl‐pyrazoles 9 a–c. Meanwhile, the synthesized thiazolyl‐pyrazoles were screened to discover their antibacterial, antifungal, antioxidant, and antitumor activities. The antibacterial screening revealed that derivatives 7 a–c, 8 a–c, and 9 a–c demonstrated minimal inhibition concentrations toward B. subtilis and S. typhimurium. While derivatives 7 c and 9 c showed respectable antifungal effectiveness against C. albicans. Further, antioxidant effectiveness of the synthesized derivatives 7 a–c and 9 a–c revealed antioxidant activity superior to derivative 8 a–c and 5 a–c compared to ascorbic acid. Likewise, thiazolyl‐pyrazole derivatives 5 a–c displayed higher cytotoxic efficacy than their corresponding derivatives 9 a–c, 8 a–c and 7 a–c, respectively.