Crystal structure of obscurine: a natural product isolated from the stem bark of B. obscura.

The title compound, C24H31NO3 {systematic name: (E)-3-[(1R*,2S*,4aS*,8aR*)-2-(benzo[d][1,3]dioxol-5-yl)-1,2,4a,5,6,7,8,8a-octa-hydro-naphthalen-1-yl]-N-iso-butyl-acryl-amide}, is a natural product isolated from the stem bark of B. obscura. It is composed of an octa-hydro-naphthalene ring system substituted with an essentially planar benzodioxole ring system [r.m.s. deviation = 0.012 Å] and an extended iso-butyl-acryl-amide group. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds, forming chains propagating along [100]. The chains are linked by pairs of C-H⋯O hydrogen bonds, involving inversion-related benzodioxole ring systems, forming ribbons lying parallel to (010). There are also C-H⋯π inter-actions present within the ribbons.