Heronamides D-F, polyketide macrolactams from the deep-sea-derived Streptomyces sp. SCSIO 03032.

Three new macrolactams, heronamides D-F (1-3), were isolated from the deep-sea-derived Streptomyces sp. SCSIO 03032 upon changing cultivation conditions. The planar structures of heronamides D-F (1-3) were elucidated by extensive MS and NMR spectroscopic analyses and comparisons with the closely related heronamides A-C. The relative configurations of 1-3 were deduced by detailed analysis of (3)JHH values and NOESY data. The absolute configurations of 1 and 2 were determined by chemical modifications and application of the modified Mosher's method. None of the compounds exhibited obvious antimicrobial or cytotoxic activities.