METHOD FOR PREPARING SYNTHETIC PROCYANIDINE OLIGOMERS Russian patent published in 2006 - IPC C07D311/62 

FIELD: organic chemistry, chemical technology, chemistry of polymers.

SUBSTANCE: invention relates to a method for preparing synthetic procyanidine oligomers, in particular, to a method for preparing procyanidine dimer. Method involves the following steps: (a) protection of each phenolic hydroxyl group of procyanidine monomer of the general formula (1): by a removable protecting group that doesn't inactivate ring A of monomer being the protection step is carried out in aprotonic solvent medium; (b) optional blocking position C-8 in monomer from step (a) by halide group; (c) activation for coupling position C-4 of compound from the stage (a) or step (b) by addition of acyloxyl group by using organic acid lead (IV) salt to obtain the activated compound, and (d) coupling the activated compound from step (c) with unprotected procyanidine monomer in the presence of the coupling catalyst to obtain a dimer. Under the definite conditions at stage (b) crystalline 8-bromo-tetra-O-benzyl-(-)-epicatechine is obtained as an intermediate substance. Invention provides the development of universal method for synthesis of oligomer with the complex configuration.

EFFECT: improved method of synthesis.

15 cl, 1 tbl, 8 dwg, 28 ex