Novel A-seco-rearranged lanostane triterpenoids from Abies sachalinensis

From the needles of Abies sachalinensis, novel rearranged lanostane type tr iterpenes, 1-4, were isolated along with a known triterpene (5). The struct ures of the new compounds, 1-4, were elucidated to be 3,4-seco-8-(14-->13R) abeo-17,13-friedo-9 beta -lanosta-4(28),7,14(30),22Z,24-pentaen-26,23-olide -3-oic acid, methyl 3,4-seco-8-(14-->13R)abeo-17,13-friedo-9 beta -lanosta- 4(28),7,14(30),22Z,24-penten-26,23-olide-3-oate, 3,4-seco-8(14-->13R)abeo-1 7,13-friedo-9 beta -lanosta-4(28),7,14,22Z,24-pentaene-26,23-olide-3-oic ac id and methyl 3,4-seco-8(14-->13R)abeo-17,13-friedo-9 beta -lanosta-4(28),7 ,14,22Z,24-pentaene-26,23-olide-3-oate, respectively, by means of spectral experiments, especially two dimensional NMR spectroscopy, such as H-1-detec ted multiple quantum coherence (HMQC), H-1-detected heteronuclear multiple bond connectivity (HMBC) and H-1-H-1-correlation spectroscopy (COSY) experi ments. These new compounds have novel structures containing A-seco, rearran ged spiro structure and a gamma -lactone conjugated with a diene. Some of t hese compounds showed potent antibacterial activity against gram positive b acteria.