| 摘要 |
Processes are disclosed for the production of linear and branched procyanidin oligomers having "n" procyanidin monomeric units where n is 2 to 18. The processes include coupling protected, activated monomers with an unprotected monomer to produce a partially protected (4†’8) dimer. The dimer is optionally blocked, coupled with an activated protected monomer to produce a partially protected, optionally blocked trimer, and deprotected. The steps can be repeated to produce higher oligomers. Processes are also provided for producing (8†’8), (8†’6), and (6†’6) dimers and doubly branched oligomers. Crystalline 8-bromo tetra- O- benzyl (-)-epicatechin is produced under certain conditions. |
