An improved environmentally benign procedure for the synthesis of various benzimidazole and benzoxazole derivatives using green solvent PEG400. We have optimized the reaction condition and it was found that PEG400 was believed to be best as compared to PEG200, PEG600 and PEG800 at 80 to 85 °C. This method provides a novel route for the synthesis of benzimidazole and benzoxazole derivatives. The main attractive features of this process are a mild reaction conditions, easy workup procedure and good to excellent yield. The structures of all the synthesized compounds were confirmed by 1H NMR, IR, MASS and Elemental Analysis.
International Letters of Chemistry, Physics and Astronomy (Volume 25)
M. D. Khunt et al., "Easy, Simplistic and Green Synthesis of Various Benzimidazole and Benzoxazole Derivatives Using PEG400 as a Green Solvent", International Letters of Chemistry, Physics and Astronomy, Vol. 25, pp. 61-68, 2014