One-Pot Synthesis of 1H-Benzimidazole Derivatives Using Thiamine Hydrochloride as a Reusable Organocatalyst

Abstract

A simple and efficient one-pot synthesis of 1H-benzimidazole derivatives using thiamine hydrochloride (VB₁) as the organocatalyst from o-phenylenediamine and aldehyde in dimethylformamide is described. Compared to classical reaction conditions, this new method consistently has the advantages of excellent yields, metal-ion-free procedure, and good recovery and reusablity of catalyst.

GRAPHICAL ABSTRACT

Keywords:

• Aldehyde
• 1H-benzimidazole
• green chemistry
• o-phenylenediamine
• thiamine hydrochloride (VB₁)

ACKNOWLEDGMENTS

This work was supported by the Chinese National Science and Technology Major Project “Key New Drug Creation and Manufacturing Program” (Grants 2009ZX09301-001, 2009ZX09102), the National Natural Science Foundation of China (Grants 90713046, 30772638, 30925040), and CAS Foundation (Grant KSCX2-YW-R-179).

Notes

^a Conditions: The reaction was carried out at room temperature.

^b Isolated yield.

^c Catalyst was reused four times.

^a The reaction was carried out at room temperature for 1.5 h.

^b Isolated yield.

^c Failed to isolate.

^a The reaction was carried out at room temperature for 1.5 h.

^b Isolated yields.

^a The reaction was carried out at room temperature for 1.5 h.

^b Isolated yield.