Nocardiopsins C and D and nocardiopyrone A : new polyketides from an Australian marine-derived Nocardiopsis sp.

A Nocardiopsis sp. (CMB-M0232) recovered from marine sediment collected off the coast of South Molle Island, Queensland, Australia, yielded two new examples of rare prolinyl-macrolactam polyketides, nocardiopsins C (1) and D (2), a new highly substituted α-pyrone polyketide, nocardiopyrone A (3), and the previously reported macrolide polyketides nocardiopsins A (4) and B (5). Structures were assigned on the basis of detailed spectroscopic analysis, degradation, and chemical derivatization. PCR amplification of CMB-M0232 genomic DNA revealed the presence of type I and type II polyketide synthase and nonribosomal peptide synthase domains.