Abstract: | Samaderin B, or (1R,2S,5R,5aR,7aS,11S,11aS,11bR,14S)‐1,7,7a,11,11a,11b‐hexahydro‐1,11‐dihydroxy‐8,11a,14‐trimethyl‐2H‐5a,2,5‐(methanoxymetheno)naphth1,2‐d]oxepine‐4,6,10(5H)‐trione, C19H22O7, and samaderin C, or (1R,2S,5R,5aR,7aS,10S,11S,11aS,11bR,14S)‐7,7a,10,11,11a,11b‐hexahydro‐1,10,11‐trihydroxy‐8,11a,14‐trimethyl‐2H‐5a,2,5‐(methanoxymetheno)naphth1,2‐d]oxepine‐4,6(1H,5H)‐dione, C19H24O7, were isolated from the seed kernels of Samadera indica and were shown to exhibit antifeedant activity against Spodoptera litura third‐instar larvae. The replacement of the carbonyl group in samaderin B by a hydroxy group in samaderin C causes conformational changes at the substitution site, but the overall conformation is not affected; however, the compounds pack differently in the crystal lattice. |