(1α,2β,3α,7α,11α,13β)-1,3,11-Triacet-oxy-2,13-bis-(benz-yloxy)-7-hydr-oxy-21-methyl-N,19-secohetisan-19-al.

The title compound (delgradine), C(41)H(43)NO(12), is a hetisine-type C(20)-diterpenoid alkaloid, isolated from the roots of Aconitum carmichaeli Debx. In the crystal structure, the mol-ecule assumes an U-shaped conformation, the terminal benzene rings being approximately parallel and partially overlapped with each other. The mol-ecule contains eight alicyclic and heterocyclic rings. Cyclo-hexane rings A and B adopt similar chair conformations; the six-membered rings C, D and E form a bicyclo-[2.2.2]octane system with a boat conformation for each six-membered ring, the six-membered heterocyclic ring F has a screw-boat conformation and both of the five-membered rings G and H have envelope conformations. The crystal structure contains inter-molecular O-H⋯O hydrogen bonding.