LAUSR

Abstract By the method of 1 H NMR prescreening and tracing the diagnostic signals, 6-methylpyridinone derivatives, (8 R ,9 S )-dihydroisoflavipucine ( 1 ), (8 S ,9 S )-dihydroisoflavipucine ( 2 ), 3-(1-hydroxy-4-methyl-2-oxopentylidene)-6-methylpyridine-2,4(1 H ,3 H )-dione ( 3 ), 4-hydroxy-3-(2-hydroxy-4-methylpentanoyl)-6-methylpyridin-2(1 H )-one ( 4 ), 4-hydroxy-3-[(4-hydroxy-6-methyl-2-oxo-2 H -pyran-3-yl)methyl]-6-methylpyridin-2(1 H )-one ( 5 ) and a known 6-methylpyranone derivative 3,3′-methylenebis(4-hydroxy-6-methyl-2 H -pyran-2-one) ( 6 ) were isolated from the marine fungus Leptosphaerulina sp., which was collected from the starfish Acanthaster planci from the South China Sea. Compounds 2 and 3 are new compounds. Their structures were elucidated on the basis of MS, 1D and 2D NMR, and X-ray single crystal diffraction data. The absolute configurations of compounds 1 and 2 were determined by analysis on the experimental circular-dichroism spectra.