Conformational analysis of the sixteen C(4)-C(6) and C(4)-C(8) linked dimers of (+)-catechin and (−)-epicatechin

✍ Scribed by V. N. Viswanadhan; Wayne L. Mattice

• Book ID: 102880694
• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 645 KB
• Volume: 7
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/jcc.540070603

✦ Synopsis

A conformational analysis has been performed for sixteen dimers of (+I-catechin and/or (-)-epicatechin using molecular mechanics (MM2). Monomer units are linked by 4a-6, 4a-8, 4p-6, and 4/34 bonds. The four possible combinations of ( +hatechin and/or (-)-epicatechin are used for each bonding pattern. The objectives are characterization of (1) the two rotational isomers at the bond between the two monomer units and (2) the conformations of the heterocyclic rings. There is a twofold rotation about the bond between monomer units. Differences in the energies at the two minima range from a few tenths of a kcal/mol to several kcal/mol, depending on the dimer. Heterocyclic rings occupy a range of conformations that can be described as half chairs with varying degrees of distortion toward C(2) or C(3) sofas. The more frequent distortion is toward the C(2) sofa. Interconversion between most of the heterocyclic ring conformations can be obtained by coordinated motion of C(2) and C(3), over a range of about 40 pm, with respect to the mean plane of the fused aromatic ring system.