Studies of the syntheses of heterocyclic compounds containing benzopyrone. Part 2. Syntheses of khellin analogues
Abstract
6-Acetoxy-4,7-dimethoxybenzofuran-5-carbonyl chloride (4), prepared from khellin (1) by three steps, was condensed with enamines or lithium enolates. Further treatment with acid afforded the khellin analogues (10). Better yields were obtained with lithium enolates than with enamines.