Condensed Heteroaromatic Ring Systems. VIII.1) Synthesis of 3-Substituted Isocoumarins from o-Halobenzoic Acid Derivatives

Abstract

The hydration of o-ethynylbenzoic acid derivatives, such as ethyl o-ethynylbenzoate, o-ethynylbenzonitrile, and o-ethynylbenzamide, in sulfuric acid in the presence of mercuric sulfate, afforded 3-substituted isocoumarins. The palladium-catalyzed reaction of o-halobenzoic acid derivatives with terminal acetylenes to obtain the starting materials for the cyclization is also described. © 1986, The Pharmaceutical Society of Japan. All rights reserved.