Cinnafragrins A-C, dimeric and trimeric drimane sesquiterpenoids from Cinnamosma fragrans, and structure revision of capsicodendrin.

Two new dimeric sesquiterpenoids and a new trimeric drimane sesquiterpenoid named cinnafragrins A-C (1-3), together with cinnamodial (4), D-mannitol, capsicodendrin (5), and a vitamin E analogue, delta-tocotrienol, were isolated from Cinnamosma fragrans, a Malagasy medicinal plant. The structures of the new compounds were determined on the basis of physical, chemical, and spectroscopic evidence. Capsicodendrin, previously isolated from Capsicodendron dinisii and tentatively suggested to be a tetramer of cinnamodial, was revised structurally as a mixture of C-12'-epimers of 12'-hydroxycinnafragrin B by extensive 2D NMR analysis and X-ray crystallography of the lactone derivative, cinnafragrolide (6). The chemosystematics of the family Canellaceae are discussed.