Novel lanostane and rearranged lanostane-type triterpenoids from Abies sachalinensis - II -

In the previous work we reported five A-seco-rearranged lanostane triterpenoids as antibacterial constituents from the ethyl acetate soluble fraction of Abies sachalinensei leaves. In further study on the isolation of constituents from the ethyl acetate soluble fraction, two new rearranged lanostane and lanostane-type triterpenoids (3, 4) and three reported compound (1, 2, 5) were isolated. The structures of new compound 3 and 4 were determined to be 3,4-seco-4(28),6,8(14),24-mariesatetraen-26,23-olide-23-hydroxy-3-oic acid and 3,4-seco-4(28),7,24-lanostatrien-26,23-olide-23-hydroxy-3-oic acid, respectively, by spectral studies on HR-MS, (1)H-NMR, (13)C-NMR, and 2D-NMR spectra. Compound 1 was identified with pindrolactone and its structure was revised as 7,14,22Z,24-mariesatetraen-26,23-olide-3alpha-ol. Structures of 2 and 5 were determined as 7,14,24-mariesatrien-26,23-olide-3alpha,23-diol and 3alpha-hydroxy-7,14,24E-mariesatrien-23-oxo-26-oic acid. Of these compounds, 2, 3 and 4 were obtained as lactol tautomer mixtures at gamma-lactone structures of side chains.