In the course of a screening program, we have isolated the new natural product, 5,7-dihydroxy-5,6,7,8-tetrahydroazocin-2(1H)-one (1), from the staurosporine producing marine-derived Streptomyces sp. strain QD518. Here we report the isolation and structure elucidation of 1 and the artifacts 3 and 4 resulting from 1 by acid catalyzed intra- and inter-molecular reactions.
Article No. XXXII on marine bacteria. For part XXXI, see: WuSJFotsoS, QinS, KelterG, FiebigHH, LaatschH. (2005) N-Carboxamido-staurosporine and selina-4(14),7(11)-diene-8,9-diol, new metabolites from a marine Streptomyces sp. Journal of Antibiotics, accepted for publication.
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Addendum during proofreading: The structures of epohelmins A and B [SakanoY, YamaguchiY, MasumaR, TomodaH, OmuraS, EbizukaY. (2004) Epohelmins A and B, novel lanosterol synthase inhibitors from a fungal strain FKI-0929. Journal of Antibiotics, 57, 564–568] were revised recently from epoxy-azocanes to hydroxyl-hexahydropyrrolizines [SniderBB, GaoX. (2005) Structure revision and syntheses of Epohelmins A and B Organic Letters, 7, 4419–4422]. It seems, however, plausible that the revised structures originated from the previous ones by a similar cyclization as described here, an both formulae were correct.
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