Crystal structure of sepaconitine, a C₁₉-diterpenoid alkaloid from the roots ofAconitum sinomontanumNakai

Abstract

The title compound [systematic name: [(1α,14α,16β)-20-ethyl-8,9,10-trihy­droxy-1,14,16-tri­meth­oxy­aconitan-4-yl 2-amino­benzoate], C30H42N2O8, a natural C19-diterpenoid alkaloid, possesses an aconitane carbon skeleton with four six-membered rings and two five-membered rings. The fused ring system contains two chair, one boat, one twist-boat and two envelope conformations. Intra­molecular N—H⋯O hydrogen bonds are observed between the amino and carbonyl groups. The mol­ecules are linked together via O—H⋯O hydrogen bonds, forming a three-dimensional framework.

C18-diterpenoid alkaloids in tribe Delphineae (Ranunculaceae): phytochemistry, chemotaxonomy, and bioactivities

“…According to single crystal X-ray diffraction analysis of corresponding C 18 -DAs, e.g., LA (37, Fig. 1B), sepaconitine (46), 30 N-deacetyllappaconitine (41), 31 and ranaconitine (102), 32 the C 18 -DAs possess stable conformations for most of the rings except for rings A and D, as they only have one or two exible atoms in the skeleta, which is identical to that of C 19 -DAs. 33,34 Generally, rings C and F in C 18 -DAs exist in envelope form, rings E and G adopt chair form, and ring B is xed in a boat conformation.…”