Patent ID: 6476241
Filing Date: 2002-11-05
Classification: C07D,Y02P

Abstract:
A process for preparing an epicatechin -4&agr;,8-epicatechin dimer which comprise the steps of:(a) protecting the 3-hydroxyl group of 5, 7, 3â€²,4â€²-tetra-O-benzyl-epicatechin with a benzyl protecting group to form 3,5,7,3â€²,4â€²-penta-O-benzyl-epicatechin; (b) oxidizing the C-4 position of the epicatechin of step (a) to form 3,5,7,3â€²,4â€²-penta-O-benzyl-4-hydroxy-epicatechin; (c) oxidizing the C-4 hydroxy group of the epicatechin of step (b) to form a (2R,3S)-3,5,7,3â€²,4â€²-penta-O-benzyl-4-ketone-epicatechin; (d) adding tert-butyllithium to 3,5,7,3â€²,4â€²-penta-O-benzyl-8-bromo-epicatechin to form a protected epicatechin lithium reagent; (e) adding the epicatechin from step (c) to the epicatechin lithium reagent from step (d) to form 3,5,7,3â€²,4â€²-penta-O-benzyl 4-hydroxy-epicatechin -4&agr;, 8-(3,5,7,3â€²,4â€²-penta-O-benzyl)-epicatechin dimer; (f) reducing the C-4 hydroxyl group of the dimer of step (e) to form 3,5,7,3â€²,4â€²-penta-O-benzyl-epicatechin-4&agr;, 8-(3,5,7,3â€²,4â€²-penta-O-benzyl)-epicatechin dimer; and (g) replacing the benzyl groups of the dimer of step (f) with hydrogen to form the epicatechin 4&agr;, 8-epicatechin dimer.