Praeruptorin A

benzo[1,2-b:3,4-b']dipyran-9-ylester, (2Z)-

9,10-Dihydro-9β-[(Z)-1-oxo-2-methyl-2-butenyloxy]-10β-(acetyloxy)-8,8-dimethyl-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one

(Z)-2-Methyl-2-butenoic acid [(9S,10S)-10β-(acetyloxy)-9,10-dihydro-8,8-dimethyl-2-oxo-2H,8H-benzo[1,2-b:3,4-b']dipyran]-9β-yl ester