An efficient synthesis of 4‐alkoxy‐5,6‐dihydro‐furo(and ‐thieno)[2,3‐<i>d</i>]pyrimidines using zinc chloride/triethylamine reagent system

Abstract

Abstract magnified image The one‐pot synthesis of 4‐alkoxy‐5,6‐dihydro‐furo(and ‐thieno)[2,3‐ d ]pyrimidines is described. The reactions of 2‐benzamido‐4,5‐dihydro‐3‐furan(and ‐3‐thiophene)carbonitriles 1a‐d and 2a‐c with ethanol and/or methanol in the presence of zinc chloride and triethylamine gave the corresponding 4‐alkoxy‐5,6‐dihydro‐furo(and ‐thieno)[2,3‐ d ]pyrimidines 3a‐d , 4a‐d , 5a‐c and 6a‐c .