Contribution à l'étude du comportement de la catéchine en milieu alcalin

Abstract

Contribution to the study of the behaviour of catechin in alkaline medium When catechin ( 1 ) is warmed with aqueous alkali it first undergoes rapid epimerisation. After some time a novel bridged carbocyclic enol, catechinic acid ( 3 ) separates out and may be isolated in excellent yield. Eventually catechinic acid isomerises to 2‐(3′,4′‐dihydroxyphenyl)‐3,9‐epoxy‐6‐oxo‐bicyclo[3,3,1]‐non‐7‐en‐8,9‐diol ( 4 ) via an open chain anion ( 5 ) which is also involved in the epimerisation of catechin. Assignments of structure are given and the equilibria observed are discussed.