| Abstract
| - The structures of polymastiamides B−F(2−6), five new steroid/amino acidconjugates isolatedfrom the Norwegian marine sponge Polymastia boletiformis,have been solved by spectroscopicanalysis of their desulfated methyl esters8−12, respectively. Polymastiamides werefound toundergo double-bond migration during treatment with MeOH/HCl to givethe Δ14,15 artifacts13 to 16. A C-ring benzenoid artifact17 was also obtained from the methylationreaction.
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