Microwave-Assisted Synthesis of 2-Substituted-4,5-diarylimidazoles from Benzoin Carboxylate Derivatives under Solvent-Free Conditions

Abstract

Benzoin carboxylate derivatives were synthesized with the aromatic aldehydes as raw material in the presence of the catalyst VB 1 . And then, benzoin carboxylate derivatives reacted with different acylating reagents under mild reaction conditions, and benzoin carboxylates were obtained. Further, 2-substituted-4,5-di(aryl)imidazoles were produced from benzoin carboxylates in the presence of solid supports Al 2 O 3 under solvent-free and microware assisted condition, and seven of them have not been reported. The reaction possessed many advantages such as mild reaction conditions, short reaction time, and no organic solvents consumed. Therefore, it is a facile and efficient synthetic method. Moreover, the synthesized compounds were characterized by 1 H NMR, 13 C NMR, IR, HRMS techniques.

Synthesis and Photophysical Properties of Multi-aryl Imidazoles Containing Nitrogen Heterocyclic Ring

“…鉴于此, 本文选用吲 哚-3-甲醛、咔唑-3-甲醛及苯偶酰和 9,10-菲醌等为原料, 设计合成了 19 个未见报道的具有拓展 π 结构的含吲哚 环或咔唑环的多取代咪唑衍生物, 结构如图 2, 测试其 紫外-可见吸收光谱和荧光发射光谱, 并筛选出光学性 图 1 红荧光蛋白 mCherry、EBFP2 和 EosFP 的荧光团 Figure 1 Fluorophores from red-emitting proteins of mCherry, EBFP2 and EosFP 均相催化剂 [29] , 以及负载型催化剂如 SiO 2 -TiCl 4 [30] 、活 性炭负载 FeCl 3 [31] 、粘土负载钛化合物 [32] 、改性氧化 铝 [33] 等. 此外, 微波辐射对合成多取代咪唑也有很好的 促进作用 [34] . 虽然在新型催化剂作用下合成多取代咪 唑类化合物方面取得了很大的进展, 但较经典的冰醋酸 作用下的合成法因冰醋酸廉价易得和低毒性, 以及绿色 环保, 仍被广泛应用 [35～38] .…”