| |
| | Five New Stilbene Dimers from the Lianas of Gnetum hainanense (Site not responding. Last check: 2007-10-19) |
 | | C NMR spectrum of 2, there were two quaternary carbons more than in that of 1 and no aliphatic carbon signals at all, which suggested that 2 was a dehydrogenated derivative of 1. |
 | | In the HMBC spectrum of 4 (Figure 1), the cross-peak between H-2(6)a and C-7a, which was attached to a hydroxy group, indicated that C-7a was excluded from the additional ring. |
 | | Therefore, considering that 4 is a dimer of a resveratrol unit and an oxyresveratrol unit, the other three aliphatic carbons probably formed a five-membered ring with two aromatic carbons as shown, which was confirmed by the cross-peaks in the HMBC spectrum. |
| pubs.acs.org /cgi-bin/jtextd?jnprdf/63/i01/html/np990382q (1861 words) |
|