An efficient synthesis of 2H-indazoles via reductive cyclization of 2-nitrobenzylamines induced by low-valent titanium reagent
作者:Fang Sun、Xian Feng、Xuan Zhao、Zhi-Bin Huang、Da-Qing Shi
DOI:10.1016/j.tet.2012.03.043
日期:2012.5
An efficient and improved synthesis of 2H-indazoles via reductive cyclization of 2-nitrobenzylamines induced by low-valenttitaniumreagent (TiCl4/Zn) is described. In this reaction triethylamine (TEA) was used to control the pH value. This method has the advantages of easily accessible starting materials, convenient manipulation, higher yield, shorter reaction time, and wider substrate scope.
A Facile One-Step Synthesis of 2-Arylindazoles via Reductive Cyclization of<i>N</i>-(2-nitroarylidene)amines
作者:Wei Lin、Minghua Hu、Xian Feng、Chengpao Cao、Zhibin Huang、Daqing Shi
DOI:10.1002/jhet.2221
日期:2015.7
A mild and efficient synthesis of 2‐arylindazole derivatives via the reductivecyclization of nitro‐aryl substrates mediated by a low‐valent titanium reagent (TiCl4/Sm/Et3N) has been developed. The attractive features of the current method include an N–N bond formation and the selective reduction of the C = N bond and nitro group, both of which were easily achieved in one‐pot by controlling the pH
通过低价钛试剂(TiCl 4 / Sm / Et 3 N)介导的硝基芳基底物的还原环化,可以温和有效地合成2-芳基吲唑衍生物。当前方法的吸引人的特征包括N–N键的形成以及C = N键和硝基的选择性还原,通过控制反应混合物的pH值,很容易在一个锅中完成这两个操作。