Preparation of 1,2‐disubstituted‐3‐hydroxy‐4(1<i>H</i>)‐quinolinones and the influence of substitution on the course of cyclization

Abstract

Abstract Synthesis of 1,2‐disubstituted‐3‐hydroxy‐4(1 H )‐quinolinones by the cyclization of N ‐substituted phenacyl or acetonyl anthranilates is described. Two methods were employed for cyclization of anthranilates. Heating in polyphosphoric acid has a wide scope of applicability. The thermal cyclization in boiling N ‐methylpyrrolidone is limited by steric effect.