Synthesis and Antimicrobial Evaluation of Some Novel Thiazole, 1,3,4-Thiadiazole and Pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine Derivatives Incorporating Pyrazole Moiety

New series of novel functionalized thiazoles, 1,3,4-thiadiazoles and pyrido [2,3-d][1,2,4]triazolo [4,3-a]pyrimidines containing pyrazole moiety were synthesized using 4-acetylpyrazole as a precursor.The structures of the compounds prepared were confirmed by both spectral and elemental analyses and by alternative synthetic routes.The mechanisms of the studied reactions were also discussed.Sixteen compounds were evaluated for their in vitro antimicrobial activity.The results proclaimed that some of the tested compounds exhibited moderate to significant antibacterial and antifungal activities.Compounds 11e, 11a, and 11d exhibited high antibacterial activity against Bacillus subtilis compared with reference drug (Ampicillin) while compounds 11a, 6g, 18e, 18a, 11d, 6a, 11c, 11b and 6d exhibited higher antifungal activity against Syncephalastrum racemosum than reference drug (Amphotericin B).