Vilsmeier-Haack reagent: A facile synthesis of 2-chloro-3-formylquinolines from N-arylacetamides and transformation into different functionalities

Abstract

A simple and regioselective synthesis of 2-chloro-3-formylquinolines through Vilsmeier-Haack cyclisation of N-arylacetamides has been reported. The cyclisation is facilitated by N-arylacetamides bearing electron donating groups at <i style="">m</i>-position. However, yields of quinolines having electron donating groups are good in all cases. Further, the nucleophilic substitution reaction of the quinolines is also investigated. Similarly, the formyl group in the quinolines is subjected to further transformation into cyano (CAN-NH₃) and alkoxycarbonyl (NIS-K₂CO₃/alcohols) groups to afford corresponding 3-cyano and 3-alkoxycarbonylquinolines, respectively.