科研之友
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摘要
The orchid Coelogyne ochracea Una was earlier chemically investigated by two Indian groups of workers who reported the isolation of six new stilbenoids, viz. coelonin [2,7-dihydroxy-4-methoxy-9,10-dihydrophenanthrene], ochrolide, ochrone A, ochrone B, ochrolic acid and ochrolone, besides the known stilbenoids batatasin-III, coelogin, coeloginin and flaccidinin. Further chemical investigation of this orchid by the present investigators has resulted in the isolation of yet two new stilbenoids, designated ochracinone and ochracinanthrone, besides 3.4,5-trimethoxybenzaltlehyde and four known stilbenoids, other than those reported earlier. viz. batatasin-III-dimethylether. flavidin. oxoflavidin and flavanthrin. The orchid Coelogyne cristata Lindl. was also earlier chemically investigated in our laboratory yielding the first pair of 9,10-dihydrophenanthropyran and pyrone, coelogin and coeloginin, and later two new phenanthrene derivatives coeloginanthrin and coeloginanthridin. Further investigation of this orchid by the present investigators afforded yet two new stilbenoids, designated coeloginone and coeloginanthrone. The structures of the four new stilbenoids ochracinone, ochracinanthrone, coeloginone and coeloginanthrone were established as 6-hydroxy-2,7,8-trimethoxy-9,10dihydro-5H-phenanthro[4,5-bcd]pyran-5-one, 6-hydroxy-2,7,8-trimethoxy-5H-phenanthro[4,5-bcd]pyran-5-one, tetramethoxy-9,10-dihydro-5H-phenanthro[4,5-bcd]pyran-5-one and 2,6,7,8-tetramethoxy-5H-phenanthro[4.5-bcd]pyran-5one, respectively, from spectral and chemical evidence. Detailed 2D NMR [1-bond center dot H-1-C-13 (HMQC) and 2- and 3-bond H-1-C-13 (HMBC) correlations] spectral studies carried out on coeloginone established unambiguous assignments of all the carbon resonances of the compound and partly those of its other three congeners.
- 出版日期2011-8
