| Abstrakt: |
Ten new sesquiterpenes, nardosinanols A−I ( 1− 9) and lemnafricanol ( 10), have been isolated from several Kenyan soft corals, i.e., from Lemnaliasp., Paralemnalia clavata, Lemnalia africana, and Rhytisma fulvum fulvum. The structures and relative stereochemistry of these compounds were elucidated by interpretation of MS, COSY ( 1H− 1H correlations), HSQC, HMBC, and NOESY NMR spectroscopic experiments and in the case of 5also by chemical transformation to compounds 11and 12. Nine compounds ( 1− 9) are based on the nardosinane skeleton ( 1– 6are nardosinanes and 7– 9nornardosinanes). Lemnafricanol ( 10) possesses a novel tricyclic skeleton. Compounds 3, 7, and 10were found to be toxic to brine shrimp with LC 50values of 4.0, 0.35, and 0.32 µM, respectively. |
