RUBRATOXINA

10-[(3,6-Dihydro-6-oxo-2H-pyran-2-yl)hydroxymethyl]-4,5,8,9,10,11-hexahydro-4,8-dihydroxy-5-(1-hydroxyheptyl)-1H-cyclonona[1,2-c:5,6-c']difuran-1,3,6-trione

9-[(3,6-Dihydro-6-oxo-2H-pyran-2-yl)hydroxymethyl]-3,4,5,8,9,10-hexahydro-1,5-dihydroxy-4-(1-hydroxyheptyl)-3-oxo-1H-cyclonona[c]furan-6,7-dicarboxylic anhydride