(1α,8β)-6β-Benzo­yloxy-6-dehydroxy­heteratisine from Aconitum zeravschanicum

The title compound, C(29)H(37)NO(6), was isolated from Aconitum zeravschanicum and exhibits anti-arhythmic activity. It is a derivative of the diterpenoid alkaloid heteratisine and as such the core framework of the mol-ecule contains four six-membered, three seven-membered and one five-membered ring. The chair conformation of one of the meth-oxy-substituted six-membered rings is different from that observed in heteratisine hydro-bromide monohydrate. In the latter case, this ring adopts a boat conformation due to a stabilizing intra-molecular N-H⋯O hydrogen bond. In the crystal structure of the title compound, there is only one acidic H atom. This hydroxyl group forms an inter-molecular O-H⋯O hydrogen bond that links mol-ecules into infinite chains along the b axis.