2-Butenoic acid, 2-methyl-, 2,3,3a,4,4a,5,7a,8,9,9a-decahydro-9-hydroxy-3,4a,8-trimethyl-2,5-dioxoazuleno(6,5-b)furan-4-yl ester (VAN) 26620-65-5 Baileyolin