Manzamenone G (1), a novel dimeric fatty-acid derivative with a new carbon-skeleton, was isolated from the Okinawan marinesponge Plakortis sp. together with manzamenone H (2), a new tyramine-containing manzamenone congener, and their structures elucidated on the basis of spectral and chemical means.
Manzamenones J (1) and K (2) and plakoridine B (3), three new oxylipins with unique carbon-skeletons related to 3,6-dioxo-4-docosenoic acid, were isolated from Okinawan marinesponges, Plakortis spp., and their structures elucidated on the basis of spectral and chemical means. Absolute stereochemisty of manzamenone A (4) was investigated by appling the modified Mosher's method developed recently for
Synthesis of plakevulin A and structure–activity relationships of itsrelatedcompounds against DNA polymerases is described. We have achieved a total synthesis and revised the structure of plakevulin A. Several analogues including untenone A, manzamenone A, and optically active plakevulin A, were prepared and tested with an enzyme inhibition assay for mammalian DNA polymerases. The effect of the methyl