Bicunningines A and B, two new dimeric diterpenes from Cunninghamia lanceolata.
Two unprecedented dimeric diterpenoids, with a 2,3-dihydrofuran ring fusing an abietane and a 4,5-seco-abietane diterpene, were isolated from Cunninghamia lanceolata. Their structures were elucidated by spectroscopic measurements, and their absolute configurations were determined by quantum chemical TDDFT ECD calculations, chemical transformations, and Mosher's method. The Mosher method carried out with MPA and MTPA esters of the sterically hindered sec-hydroxyl group gave contradictory results, while MPA afforded the correct absolute configuration.
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu-Chong-Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, China.
Xian-Feng
XF
Hou
Sheng
S
Yao
Attila
A
Mándi
Tibor
T
Kurtán
Chun-Ping
CP
Tang
Chang-Qiang
CQ
Ke
Xi-Qiang
XQ
Li
Yang
Y
Ye
D032486:Cunninghamia / Q000737:chemistry*; D019281:Dimerization; D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification; D008958:Models, Molecular; D008968:Molecular Conformation
D004224:Diterpenes; C571215:bicunningine A; C571214:bicunningine B