Synthesis of Amide and Ester Derivatives of Naphthopyrone Carboxylic Acid

Abstract

in Wiley Online Library (wileyonlinelibrary.com).The synthesis of various amide and ester derivatives of naphthopyrone-2-carboxylic acid has been carried out by reaction of 1-naphthol with dimethyl acetylenedicarboxylate, which gave a mixture of E and Z isomers of naphthoxy diester. The diester on hydrolysis with KOH gave corresponding diacid, which was a mixture of E and Z isomers. The E and Z isomers were difficult to separate, which were subjected to cyclization in sulfuric acid to get cyclized naphthopyrone carboxylic acid. This acid is converted into titled compounds.