球磨机中无溶剂合成1,2-双取代苯并咪唑

Solvent-free synthesis of 1,2-disubstitued benzimidazoles in ball mill

摘要:

球磨机中无溶剂条件下，FeCl3•6H2O催化邻苯二胺与芳香醛反应，选择性生成1-芳甲基-2-芳基双取代苯并咪唑，产率均在80%以上。产物结构经1H NMR、13C NMR及HRMS表征。最佳反应条件为：球磨机转速400 r/min，n (FeCl3•6H2O) : n (邻苯二胺) : n (芳香醛) = 0.25 : 1 : 2，研磨时间2 h。此法无溶剂、操作简单，条件温和，环境友好，具有大量制备苯并咪唑的潜能。

Abstract:

1,2-Disubstitued benzimidazoles were selective synthesized in excellent yields by the condensation of o-phenylenediamine with aromatic aldehydes under mechanically activated solvent-free conditions in ball mill using FeCl3•6H2O as the catalyst. Structures of products were characterized by 1H NMR, 13C NMR and HRMS. The optimum conditions were given: n (FeCl3•6H2O) : n (o-phenylenediamine) : n (aldehydes) = 0.25 : 1 : 2 and the ball mill was run with a rotational speed of 400 r/min for 2 h. The reaction was carried out without solvent and just needed a simple work-up procedure. This mild and eco-friendly method had the potential for facile preparation of benzimidazole derivatives.