| 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.
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