Patent ID: 7126014

Claim:
A process for preparing epicatechin-(4α,8)-catechin dimer, which process comprise the steps of: (a) protecting the 3-hydroxyl group of 5,7,3′,4′-tetra-O-benzyl-epicatechin with a benzyl protecting group to form 3,5,7,3′,4′-penta-O-benzyl-epicarechin; (b) oxidizing the C-4 position of the epicarechin of step (a) to form 3,5,7,3′,4′-penta-O-benzyl-4-hydroxy-epicate; (c) oxidizing the C-4 hydroxyl group of the epicatechin of step (b) to form (2R,3S)-3,5,7,3′,4′-penra-O-benzyl-4-ketone-epicatechin; (d) adding tert-butyl lithium to 3,5,7,3′,4′-penta-O-benzyl-8-bromo-catechin to form a catechin-lithium reagent; (e) adding the epicatechin from step (c) to the catechin-lithium reagent from step (d) to form 3,5,7,3′,4′-penta-O-benzyl-4-hydroxy-epicatechin-(4α,8)-(3,5,7,3′,4′-penta-O-benzyl)-catechin dimer; (f) reducing the C-4 hydroxyl group of the dimer from step (e) to form 3,5,7,3′,4′-penta-O-benzyl-epicatechin-(4α,8)-(3,5,7,3′,4′-penta-O-benzyl)-catechin dimer; and (g) replacing the benzyl groups of the dimer of step (f) with hydrogen to form the epicatechin-(4α,8)-catechin dimer.