Actinofuranones A and B, Polyketides from a Marine-Derived Bacterium Related to the Genus Streptomyces (Actinomycetales)

Two new polyketides, actinofuranones A (1) and B (2), were isolated from the culture extract of a marine-derived Streptomyces strain designated CNQ766. The structures of 1 and 2 were elucidated by interpretation of NMR and other spectroscopic data and by chemical derivatization. The relative stereochemistries of these new molecules were assigned on the basis of analysis of NOE data and vicinal (1)H-(1)H coupling constants, while the absolute configurations of the asymmetric centers were determined using the modified Mosher's method.