Flavonoid intermediates for the synthesis of mopanol trimethyl ether[trans-trans-7,7',8'-Trimethoxyisochromano(4',3':2,3)chroman-4-ol]

Abstract

Preparation of a number of intermediates for the synthesis of (±)-mopanol trimethyl ether is described, together with exploratory reactions with model compounds, and especially with 7-methoxyflavanone-2'-carboxylic acid. 7-Methoxyflavan-4-ol, the initial product from reduction of 7-methoxyflavanone-2'-carboxylic acid with complex metal hydrides, was found to undergo facile dehydration to a novel intramolecular dibenzyl ether [the cyclic ether (19)*]. It was noted that the methoxymethyl group, which may be used as a protecting group for phenols, did not survive the conditions of methylation with dimethyl sulphate and potassium carbonate in acetone.