2-Butenoic acid, 2-methyl-, 9,10-dihydro-8,8-dimethyl-10-(3-methyl-1-oxobutoxy)-2-oxo-2H,8H-benzo(1,2-b:3,4-b')dipyran-9-yl ester, (9S-(9alpha(Z),10alpha))- 3'-Angeloyl-4'-isovalerylkhellactone 78478-28-1 Praeruptorin E