Synthetic Studies on Naturally Occurring Coumarins: II: Synthesis of 6,7-Dimethoxy- and 7,8-Dimethoxy-5-[(E)-3-oxo-1 -buteny 1] coumarins

Abstract

In connection with studies on the structure elucidation of the so-called Reisch’s coumarin isolated from Toddalia asiatica, syntheses of two coumarins (4 and 5) were accomplished via the routes shown in Charts 2 and 3, respectively. Melting points and NMR data of the synthesized coumarins (4 and 5) and of related coumarins (5-methoxysuberenon, toddalenone, and Reisch’s coumarin) are given in Table I, suggesting that so-called Reisch’s coumarin might be 4. © 1992, The Pharmaceutical Society of Japan. All rights reserved.