Rearranged Lanostane Triterpenoids from Abies sachalinensis (III)

To isolate more rearranged lanostane-type triterpenes from Abies sachalinensis, continuous chemical investigation of the ethyl acetate soluble fraction of the methanol extract of A. sachalinensis afforded two new rearranged lanostane-type triterpenes(1,2). Their structures were elucidated to be 3,4-seco-4(28),7,12,24-mariesatetraen-26,23-olide-23-hydroxy-3-oic acid (1) and ethyl 3,4-seco-8(14→13R)abeo-17,13-friedo-4(28),7,14,24-lanostatetraen-26,23-olide-23-hydroxy-3-oate (2), respectively. The structure of these compounds was determined by spectral studies, especially by two-dimensional (2D)-NMR and high-resolution(HR)-MS. Compounds 1 and 2 have a tautomeric lactone structure in the side chain.