The Vilsmeier cyclization of 2′-azido and 2′-aminochalcones -: a mild one pot synthesis of 2-aryl-4-chloroquinoline and its N-formyl-1,2-dihydro derivatives

The Vilsmeier cyclization of 2'-aminochalcones provides a mild one pot synthesis of 2-aryl-4-chloro-N-formyl-1,2-dihydroquinolines. The scope of the reaction has been extended for the synthesis of quinolines themselves, by replacing 2'-aminochalcones with 2'-azidochalcones as the starting material. The yields are reasonably good and a plausible mechanism for the formation of the products in each case has been discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.