5H,17H,1,23:11,13-Diethano-2H,14H-(1,11)dioxacycloeicosino(2,3-b:12,13-b')dipyridin-4a(24aH)-ol, octadecahydro-28-methyl-, (4aR*,11R*,12aS*,16aS*,23R*,24aS*,28S*)-(+)- 88840-01-1 Xestospongin B Xestospongine B