3,3-Dimethyl-11-(3-methyl-but-2-enyl)-3H,12bH-4,8,13-trioxa-dibenzo[a,i]fluorene-6b,10-diol 3H,7H-pyrano[2',3':6,7]benzofuro[3,2-c][1]benzopyran-6b,10(12bH)-diol, 3,3-dimethyl-11-(3-methyl-2-butenyl)-, (6bS,12bS)- Erysubin E InChI=1/C25H26O5/c1-14(2)5-6-15-11-17-21(12-19(15)26)28-13-25(27)18-7-8-20-16(22(18)29-23(17)25)9-10-24(3,4)30-20/h5,7-12,23,26-27H,6,13H2,1-4H3/t23-,25+/m0/s rel-(6bR,12bR)-3,3-dimethyl-11-(3-methylbut-2-en-1-yl)-3H,7H-chromeno[6',5':4,5]furo[3,2-c]chromene-6b,10(12bH)-diol (non-preferred name)