A Green Ultrasound Synthesis Characterization and Antibacterial Evaluation of 14-Disubstituted 123-Triazoles Tethering Bioactive Benzothiazole Nucleus

摘要

The synthesis of N-(benzo[d]thiazol-2-yl)-2-(4-substituted-1H-1,2,3-triazol-1-yl)acetamides >5a–>r via the 1,3-dipolar cycloaddition reaction between 2-azido-N-(benzo[d]thiazol-2-yl)acetamide derivatives >3a–>c and different alkynes were performed in the presence and absence of ultrasound irradiation. The synthesis was carried out using t-BuOH/H2O (1:1, v/v) as reaction solvents and CuSO4·5H2O/sodium ascorbate as the catalyst. The copper catalyst was implemented to provide the regioselective 1,4-disubstituted 1,2,3-triazoles >5a–>r. Significant reductions in reaction times with comparably higher yields were observed when the reactions were carried out under ultrasound irradiation. The structures of the newly synthesized 1,2,3-triazoles were elucidated by IR, NMR, MS, and elemental analyses. They were also screened for their antimicrobial activity against three gram-positive (Streptococcus pneumonia, Bacillus subtilis, and Staphylococcus aureus), three gram-negative (Pseudomonas aeuroginosa, Escherichia coli, and Klebsiella pneumonia), and two fungal strains (Aspergillus fumigates and Candida albicans). Most of the tested compounds displayed promising antimicrobial activities at a Minimum Inhibition Concentration (MIC) of 4–16 μg/mL.