机械力化学法无溶剂合成β-苯并咪唑乙基丙二酸二甲酯类化合物

Synthesis ofβ-Benzimidazole Ethylmalonate Dimethyl Esters by Mechanochemical Method Without Solvent

苯并咪唑类衍生物在材料、医药、化工和农药等领域有重要价值,发展绿色简洁的方法来合成这一类化合物具有重要意义。采用机械力化学法以供-受体环丙烷二甲酯与苯并咪唑为原料,通过筛选不同的路易斯酸、液体研磨辅助剂、反应时间以及振动频率,优化得到了较佳的实验条件:三氟甲烷磺酸镱为催化剂,振动频率为35 Hz,球磨反应时间为1.5 h。在此条件下,以42.9%~77.5%收率合成10个β-苯并咪唑乙基丙二酸二甲酯类化合物(3a~3j),其结构经^(1)H NMR、HR-MS(ESI)表征。该合成方法具有反应条件温和、操作简单、无溶剂且底物拓展性好等优点。

Benzimidazole derivatives have important value in the fields of materials,medicine,chemicals,and pesticides,and it is of great significance to develop environmentally friendly and simple methods to synthesize these compounds.In this article,the mechanochemistry method was used to take the donor-acceptor cyclopropanes dimethyl ester and benzimidazole as raw materials.By screening different Lewis acids,liquid grinding aids,reaction time,and vibration frequency,the experimental conditions were finally determined:Yb(OTf)3 as catalyst,vibration frequency of 35 Hz,and ball milling reaction time of 1.5 h.Finally,tenβ-Benzimidazole ethyl dimethyl malonate compounds(3a~3j)were synthesized with yields of 42.9%to 77.5%,their structures were characterized by^(1)H NMR,HR-MS(ESI).This synthesis method has the advantages of mild reaction conditions,simple operation,solvent-free,and good substrate expansion.