Synthesis of some novel pyrazoline-thiazole hybrids and their antimicrobial activities

A series of novel thiazolyl pyrazolines 7a-h, 9a-f, and 11a-f have been synthesized by the reaction of thioamide derivatives 5a,b with 1-aryl-2-bromoethanones 6a-d, chloroacetones 8a-c, and hydrazonoyl chlorides 10a-c. Additionally, pyrazoles 15a-c and 20 were prepared starting from enaminone 13. These newly synthesized compounds were screened for their in vitro antibacterial activity against four bacterial species. Compound 11b showed a moderate activity against Klebsiella pneumoniae. Compounds 7c and 11c revealed a moderate activity against Pseudomonas aeruginosa. In addition, the antifungal activity of the newly synthesized compounds was determined against five fungal strains. Compounds 7e, 7g, and 11e showed a good activity against Aspergillus flavus and Penicillium expansum.