Pyrrolidinium Acetate (PyrrIL) as a Green and Recyclable Catalyst: Synthesis of 2-Phenyl Benzimidazoles and 2-Phenyl Benzothiazoles under Solvent-Free Conditions at Room Temperature

Benzimidazoles and benzothiazoles are a class of pharmaco-logically potential compounds, which exhibited antimicrobial, antican-cer, and anti-inflammatory activities. These can be obtained by simple condensation of o-phenylenediamine or o-aminothiophenol with aro-matic aldehydes. The synthetic protocol can be accomplished/improved by varying reaction parameters such as temperature, solvents, and cat-alysts. To develop such condensation reactions in a sustainable way, nontoxic solvents and eco-friendly catalysts are presently used. In this study, we proposed a novel and interesting strategy for obtaining di-versely substituted 2-phenyl benzimidazole and 2-phenyl benzothiazole derivatives via a one-pot protocol, employing pyrrolidinium ionic liquid as a green and environmentally benign catalyst under solvent-free condi-tions at room temperature in an open atmosphere. The resulting prod-ucts were obtained in good to excellent yields within a short reaction time (3-20 min). A plausible mechanism was also discussed.