HETEROCYCLES FROM SUBSTITUTED AMIDES .6. NEW CARBOSTYRIL SYNTHESIS FROM ALPHA-SUBSTITUTED ACETAMIDES AND THE VILSMEIER REAGENT

Reaction of tertiary α‐substituted acetanilides with Vilsmeier reagent has been found to give 1,3‐disubstituted‐carbostyrils, 1. α‐Chloro‐N‐(1‐cyclohexen‐1‐yl) acetamides are similarly converted to tetrahydro carbostyrils 2 and 3. The method appears useful for the preparation of a variety of 1,3‐substituted 2(1H) quinolinones. The scope and mechanism of the reaction has been investigated, with evidence presented to indicate the ring‐closure proceeds via electrophilic attack of Vilsmeier reagent on intermediate chlorenamine. Copyright © 1979 Journal of Heterocyclic Chemistry