An efficient low melting mixture mediated green approach for the synthesis of 2-substituted benzothiazoles and benzimidazoles

Abstract

Benzothiazole (BTA) and benzimidazole (BIA) derivatives are unique structures having extensive applications in material sciences, medicinal chemistry, and supramolecular chemistry in addition to their immense utilization in diverse fields, which provide sufficient impetus to develop facile synthetic methods. Bearing the prominence of these vital scaffolds in mind, herein we revealed a simple yet straightforward method without involving any external catalyst as well as conventional volatile organic solvent to assemble a vast variety of 2-substituted BTA/BIA derivatives through the condensation of 2-aminobenzenethiol and/or o-phenylenediamine with aliphatic/aromatic aldehydes in presence of low melting mixtures. In this study, although, diverse deep eutectic mixtures were tested but N,N′-dimethyl urea (DMU) with L-(+)-tartaric acid (TA) in 7:3 ratio and citric acid (CA) with DMU in 4:6 ratio were found to be the best choices. Hopefully, the present method will be useful to generate diverse heterocyclic systems and will boost the applicability of deep eutectic mixtures in modern organic syntheses.

Keywords

• Benzimidazole
• Benzothiazole
• Aromatic aldehyde
• N,N′-dimethyl urea
• Citric acid
• L-(+)-tartaric acid