Synthesis and Antimicrobial Evaluation of Novel Triazole, Tetrazole, and Spiropyrimidine-Thiadiazole Derivatives

Abstract

The aim of the present work was the synthesis of some new heterocyclic compounds derived from 6-(2,4-dimethyl-3H-benzo[f][1,3,5]triazepin-3-yl)-2-thioxo-2,3-dihydropyrimidin-4(1H)-one (1) and 6-(2,4-dimethyl-3H-benzo[f][1,3,5]triazepin-3-yl)-2-hydrazinyl- pyrimidin-4(3H)-one (3). A series of novel triazole, tetrazole, and spirocyclic (pyrimidine and thiadiazole) derivatives were synthesized in moderate to excellent yields (61%–95%). The products were obtained under moderate reaction conditions. The structures of the new compounds were confirmed using different spectroscopic methods such as UV, IR, NMR, MS, and elemental analysis. The in vitro antimicrobial activity was evaluated for the synthesized compounds against Gram-positive bacteria (Rhodopseudomonas fp., Bacillus cereus, and Micrococcus luteus) and Gram-negative bacteria (Escherichia coli (HD 701) and Salmonella typhi) as well as fungi including Alternaria alternate, Aspergillus flavus (ATCC-24556), Candida albicans (ATCC 15056) and Curvularia lunata. Benzo[f][1,3,5]triazepine derivatives exhibited potent antimicrobial activity against Gram-positive, and Gram-negative bacteria and fungi (MIC 1–11 µmol L−1) and the results were comparable to the positive controls levofloxacin (MIC 2–5 µmol L−1) and nystatin (MIC 1–3 µmol L−1).