Crystal structure of Staudtienic acid, a diterpenoid from Staudtia kamerunensis Warb. (Myristicaceae).

This title compound, C20H26O2, was isolated from the benzene fraction of the stem bark of Staudtia kamerunensis Warb. (Myristicaceae) using column chromatography techniques over silica gel. The compound was fully characterized by single-crystal X-ray diffraction, one and two-dimensional NMR spectroscopy, IR and MS spectrometry. The compound has two fused cyclo-hexane rings attached to a benzene ring, with a carb-oxy-lic acid on C-4. This cyclo-hexene ring has a chair conformation while the other adopts a half-chair conformation. The benzene ring is substituted with a propenyl moiety. The structure is characterized by inter-molecular O-H⋯O hydrogen bonds, two C-H⋯O intra-molecular hydrogen bonds and two C-H⋯π inter-actions. The mol-ecular structure confirms previous studies carried out by spectroscopic techniques.