Isolation and Structural Determination of New Pyridone Alkaloids from a fungus Chaunopycnis sp. 13ETF032

Fungi are eukaryotic organism that is ability to produce an important source of structurally unique and biologically active secondary metabolites. During our efforts to isolate diverse secondary metabolites from soil fungi, we discovered two new pyridone-type compounds (1 and 2) using various column chromatographies from the cultured extract of a fungus Chaunopycnis sp. 13ETF032 isolated from a soil sample collected in Wi-island, Korea. The chemical structure of new compounds was elucidated by 1D-, 2D-NMR and HR-MS experiments. The relative configuration of new compounds was assigned by ROESY, 1D-NOE experiments and coupling constants. Compound 1 and 2 shows structural similarities with fusaricide, leporin A, cordypyridone C, epipyridone, and N-deoxy-PF1140. Compound 2 had the similar relative configuration to PF1140 and N-deoxy-PF1140. But, compound 1 had the different relative configuration to fusaricide, cordypyridone C, and epipyridone. The stereochemical assignments and biological activities of compound 1 and 2 are still in progress.