Showing structure for methyl (2s,4ar,6ar,7r,9s,10as,10br)-9-(acetyloxy)-2-[(2r)-2-hydroxy-5-oxo-2h-furan-3-yl]-6a,10b-dimethyl-4,10-dioxo-octahydro-1h-naphtho[2,1-c]pyran-7-carboxylate