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

Abstract

According 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.