28812-09-1

[Z,(-)]-2-Methyl-2-butenoic acid 7,8-dihydro-8,8-dimethyl-7-[(3-methyl-1-oxo-2-butenyl)oxy]-2-oxo-2H,6H-benzo[1,2-b:5,4-b]dipyran-6-yl ester