2H-benzo[g]pyrano[2,3,4-ij][2]benzopyran-5-acetic acid, 5,6-dihydro-11-hydroxy-2-(2-oxopropylidene)-, (2Z)- InChI=1/C20H16O6/c1-10(21)5-13-8-16-19-12(7-14(25-16)9-17(23)24)6-11-3-2-4-15(22)18(11)20(19)26-13/h2-6,8,14,22H,7,9H2,1H3,(H,23,24)/b13-5 [(2Z)-11-hydroxy-2-(2-oxopropylidene)-5,6-dihydro-2H-benzo[h]pyrano[2,3,4-de]chromen-5-yl]acetic acid