Reevaluating the synthesis of 2,5‐disubstituted‐1 H ‐benzimidazole derivatives by different green activation techniques and their biological activity as antifungal and antimicrobial inhibitor

Abstract A comparative study concerned with the preparation of diversely substituted‐1 H ‐benzimidazole under different green activation techniques and conventional methods is reported. Data are collected for infrared, ultrasound, microwave, and simultaneous irradiation with US and IR sources, as this last strategy shows an important improvement. Further, the small library of potentially bioactive benzimidazole 17‐76 synthesized was screened as an antifungal and antimicrobial agent. Strong activity against Candida albicans and Staphylococcus aureus was observed. Remarkably, 2‐(4‐aminophenyl)‐5‐phenylamino‐1 H ‐benzimidazole 63 resulted better than that of reference drugs miconazole with a zone of inhibition up to 42 mm. Likewise, 2‐(2‐aminophenyl)‐1 H ‐benzimidazole 21 showed substantial antimicrobial activity against MRSA strain. When assayed by the microdilution method, this azaheterocyclic compound presented a minimum inhibitory concentration (MIC) ≥ 16.4 μg/100 mL and a bacterial percentage reduction of 96%.