Naphthomycins L-N, ansamycin antibiotics from Streptomyces sp. CS.

Previous analyses of the naphthomycin biosynthetic gene cluster and a comparison with known naphthomycin-type products from Streptomyces sp. CS have suggested that new products can be found from this strain. In this study, screening by LC-MS of Streptomyces sp. CS products formed under different culture conditions revealed several unknown peaks in the product spectra of extracts derived from oatmeal medium cultures. Three new naphthomycins, naphthomycins L (1), M (2), and N (3), and the known naphthomycins A (4), E (5), and D (6) were obtained. The structures were elucidated using spectroscopic data from 1D and 2D NMR and HRESIMS experiments.