3,5-Dimethoxy-3-(1,1-dimethylprop-2-enyl)-3,4-dihydropsoralen-4-one 5H-furo[3,2-g][1]benzopyran-5,7(6H)-dione, 6-(1,1-dimethyl-2-propenyl)-4,6-dimethoxy- 6-(1,1-Dimethyl-allyl)-4,6-dimethoxy-furo[3,2-g]chromene-5,7-dione 6-(1,1-dimethylprop-2-en-1-yl)-4,6-dimethoxy-5H-furo[3,2-g]chromene-5,7(6H)-dione InChI=1/C18H18O6/c1-6-17(2,3)18(22-5)15(19)13-12(24-16(18)20)9-11-10(7-8-23-11)14(13)21-4/h6-9H,1H2,2-5H