An improved Pfitzinger reaction for the direct synthesis of quinoline-4-carboxylic esters/acids mediated by TMSCl
2018
Zhou, Pan | Hu, Biao | Zhao, Siyuan | Zhang, Qiaohe | Wang, Yanqin | Li, Xiang | Yu, Fuchao
An efficient and facile synthesis of quinoline-4-carboxylic esters/acids by TMSCl-promoted reaction of easily available N,N-dimethylenaminones and isatins in alcohols/water has been developed. The improved Pfitzinger reaction involves esterification and cyclization in one-step process, and in situ formed a carboxylic ester/acid group (CO₂R or COOH) at the 4-position of quinoline ring. Moreover, the key features of this protocol are readily available starting materials, good functional group tolerance, mild reaction conditions, operational simplicity, and feasibility of scale up.
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