An imidazopyridinone and further metabolites from streptomycetes [1]

Screening and chromatographic analysis of the extracts from the terrestrial streptomycete GW5127 and from the marine Streptomyces sp. isolate B7967 yielded four new metabolites, i.e. 8-ethyl-6,11-dihydroxy-1-methoxy-naphthacene-5,12- dione (1a), 4-acetyl-1,3-dihydro-imidazo[4,5-c]pyridin-2-one (4a), 5-hydroxmethyl-4-hydroxy-2,4-dimethyl-2-cyclopentenone (6), and N-[2-(3′-hydroxy-4′-methoxyphenyl)-ethyl]-acetamide (5a), along with five known compounds, α-rubromycin (2), γ-rubromycin (3), 2-(3′-hydroxy-4′-methoxyphenyl)ethanol (5b), uracil, and N-acetyltyramine. The structures of the new compounds were deduced from high resolution mass, 1D and 2D NMR spectra and by comparison with related compounds from the literature. The antibiotic activity of the crude extracts was due to 2 and 3.