Unusual 2,3-secofernane triterpenoids
Sunday, April 12, 2009

Alstonic acids A and B, unusual 2,3-secofernane triterpenoids from Alstonia scholaris

Fei Wang, Fu-Cai Ren, Ji-Kai Liu*

Alstonic acids A and B (1-2) with a novel 2,3-secofernane framework were isolated from the leaves of Alstonia scholaris, together with a new indole alkaloid N1-methoxymethyl picrinine (3). Their structures were elucidated on the basis of extensive spectroscopic analysis, and that of 1 was confirmed by single crystal X-ray diffraction studies. This is the first report of natural occurrence of 2,3-secofernane triterpenoid, and the biosynthetic pathway of 2 involves an unprecedented cyclization between C-3 and C-9.

Reference: Phytochemistry, 2009, 70(5): 650-654.