58828-82-3 B611103K804 NSC305728 Picrasan-21-oic acid, 15-[(3,4-dimethyl-1-oxopentyl)oxy]-13,20-epoxy-3,11,12-trihydroxy-2,16-dioxo-, methyl ester, (4.xi.,11.beta.,12.alpha.,15.beta.)- TETRAHYDROBRUCEANTIN