6-(acetyloxy)-3,4a,5-trimethyl-9-oxo-4,4a,5,6,7,8,8a,9-octahydronaphtho[2,3-b]furan-4-yl 2-methylpropanoate InChI=1/C21H28O6/c1-10(2)20(24)27-19-16-11(3)9-25-18(16)17(23)14-7-8-15(26-13(5)22)12(4)21(14,19)6/h9-10,12,14-15,19H,7-8H2,1-6H propanoic acid, 2-methyl-, 6-(acetyloxy)-4,4a,5,6,7,8,8a,9-octahydro-3,4a,5-trimethyl-9-oxonaphtho[2,3-b]furan-4-yl ester