2-Butenoic acid, 2-Methyl-, anhydride

2-Butenoic acid,2-methyl-,(3aR,4S,6R,10Z,- 11aR)-2,3,3a,4,5,6,7,11a-octahydro-6,10- dimethyl-3-methylene-2,7-dioxo-6,9-epoxycyclodeca[ b]furan-4-yl ester,(2Z)-

2-Butenoic acid, 2-methyl-, 2, 3,3a,4,5,6,7,8,9,11a-decahydro-7, 9-dihydroxy-10-(hydroxymethyl)-6-methyl-3-methylene-2-oxo-6, {9-epoxycyclodeca[b]furan-4-yl} ester, {[3aR-[3aR*,4R*(Z),6R*,7S*,} 9R*,10

2-Butenoic acid,2-methyl-, hexyl ester, (2E)-

2-Butenoic acid,2-methyl-,2,3,3a,4,5,7,7a,8a,- 8b,8c-decahydro-4-hydroxy-6,8a-dimethyl- 3-methylene-2-oxooxireno[2,3]azuleno[4,5-b]- furan-5-yl ester

2-Butenoic acid, 2-Methyl-, 1-Methylbutyl ester

2-Butenoic acid,2-methyl-,decahydro-5,14,- 15-trihydroxy-1,3-dimethyl-9-methylene-2H,- 7H-7,10-ethano-7a,3,6a-[1]propanyl[3]- ylidenepentaleno[1,2-b]azocine-11,12-diyl ester,[3S-[3R,5â,6aR,7&aci