Lewis acid catalyst free synthesis of benzimidazoles and formamidines in 1,1,1,3,3,3-hexafluoro-2-propanol

A simple, inexpensive, environmentally friendly and efficient route for the synthesis of benzimidazole and formamidine derivatives by the reaction of O-phenylenediamines or amines with orthoesters using hexafluoroisopropanol as a solvent/catalyst is described.

Figure optionsDownload as PowerPoint slideResearch highlights▶ Synthesis of benzimidazole and formamidine derivatives. ▶ Synthesis of unsymmetrical formamidine derivatives. ▶ Using hexafluoroisopropanol as a solvent. ▶ A new medium for activation of orthoesters. ▶ Ease of product isolation/purification by non-aqueous work-up.