Copper-catalyzed [2+3]-annulation of N–H imines with vinyl azides: access to polyaryl 2<i>H</i>-imidazoles
作者:Zhongzhi Zhu、Hanze Lin、Baihui Liang、Junjie Huang、Wanyi Liang、Lu Chen、Yubing Huang、Xiuwen Chen、Yibiao Li
DOI:10.1039/c9cc10042c
日期:——
A practical method for the synthesis of 2H-imidazoles via a [2+3] annulation of N-H imines with vinylazides using a copper catalyst is developed. In this conversion, environmentally friendly oxygen is used as the sole oxidant and N2 and H2O are the only by-products. The catalytic transformation, operating under mild conditions, is operationally simple and is considered as a readily available catalytic
Electrocarboxylation of <i>N</i>-Acylimines with Carbon Dioxide: Access to Substituted α-Amino Acids
作者:Ke Zhang、Xiao-Fei Liu、Wen-Zhen Zhang、Wei-Min Ren、Xiao-Bing Lu
DOI:10.1021/acs.orglett.2c01267
日期:2022.5.20
Direct electrocarboxylation of various N-acylimines with atmospheric CO2 is achieved in an undivided cell under mild conditions, affording substituted α-amino acids in yields of 62–95%. This reaction is conducted with high efficiency using triethanolamine as an external reductant under nonsacrificial anode conditions, and can be facilely performed on gram scale. Preliminary mechanistic studies including
各种N-酰基亚胺与大气 CO 2的直接电羧化是在温和条件下在未分裂的电池中实现的,以 62-95% 的产率提供取代的 α-氨基酸。该反应在非牺牲阳极条件下使用三乙醇胺作为外部还原剂高效进行,并且可以轻松地以克级进行。包括循环伏安法和对照实验在内的初步机理研究支持N自由基碳负离子作为关键中间体。
Process for producing benzophenone-azines
申请人:MITSUBISHI GAS CHEMICAL COMPANY, INC.
公开号:EP0038708A1
公开(公告)日:1981-10-28
A process for producing a benzophenone-azine which comprises reacting a benzophenone-imine with molecular oxygen in the presence of a catalyst composed of dissolved copper in amount of 0.0005 - 0.01 mol per 1 mol of the benzophenone-imine in terms of copper atom.
A process for preparing a hydrazine hydrohalide comprising the steps of:
(a) oxiding a benzophenone-imine with molecular oxygen in the presence of a copper halide catalyst to produce benzophenone-azine;
(b) contacting the oxidation reaction mixture with an aqueous solution containing a hydrohalic acid thereby hydrolyzing the benzophenone-azines to produce a hydrazine hydrohalide and, simultaneously extracting and removing the catalyst with the hydrohalide acid-containing aqueous solution to obtain an aqueous solution containing the hydrazine hydrohalide and the catalyst;
(c) separating the aqueous solution and adjusting the solution to a pH of from 3 to 7 with an alkali;
(d) contacting the aqueous solution with a benzophenone-imine to extract the catalyst;
(e) separating the catalyst-containing benzophenone-imines solution from the aqueous solution containing the hydrazine hydrohalide to recover the hydrazine hydrohalide and to recycle the catalyst-containing benzophenone-imine solution to step (a).
The process is advantageous in that the catalyst is easily recovered for reuse.