A simple, convenient, and environmentally benign protocol for the synthesis of benzimidazoles from ortho-phenylenediamines and aldehydes via aerobic oxidation was developed in wet organic solvents. Notably, water significantly accelerated this transformation, which allowed us to achieve this important transformation without the assistance of any metal catalysts and other co-oxidants. Mechanistic studies
A simple and efficient method for the synthesis of benzazoles via Cu-catalyzed aerobic oxidative condensation of o-amino/mercaptan/hydroxyanilines with benzylamines was developed.
开发了一种简单高效的方法,通过铜催化的有氧氧化缩合反应,将邻氨基/硫醇/羟基苯胺与苄胺合成苯并呱。
Electrochemical Synthesis of Benzazoles from Alcohols and <i>o</i>
-Substituted Anilines with a Catalytic Amount of Co<sup>II</sup>
Salt
作者:Yin-Long Lai、Jian-Shan Ye、Jing-Mei Huang
DOI:10.1002/chem.201505074
日期:2016.4.4
electrochemical synthesis of benzazoles directly from alcohols and o‐substitutedanilines has been developed. The reaction conditions have been optimized by varying the composition of the electrolyte and the metal salt used as catalyst. The cyclization proceeds smoothly with a catalytic amount of a cobalt salt under air at room temperature to afford 2‐substituted benzimidazoles, benzothiazoles, and benzoxazoles
An Efficient and Environmental Benign Synthesis of 2-benzimidazoles and 2-benzothiazoles Using CeCl<sub>3</sub>-NaI as Catalyst
作者:Xun Zhu、Yunyang Wei
DOI:10.3184/174751913x13575704209748
日期:2013.2
A one-pot condensation of an aldehyde with 1,2-phenylenediamine or 2-aminothiophenol in dimethyl carbonate at 100 °C under O2 in the presence of catalytic amounts of CeCl3–NaI gave an imine intermediate, which cyclised and dehydrogenated to give 2-arylbenzimidazoles or 2-arylbenzothiazoles in good yields.
practical intramolecular C–H amidation methodology has been developed using molecular iodine under basic conditions. The required imine substrates were readily obtained by condensation of simple o-phenylenediamine derivatives and aldehydes. The transition-metal-free cyclization reaction described here works well with crude imines and allows for the sequential synthesis of N-protected benzimidazoles