Crystal structure and Hirshfeld surface analysis of 3-oxours-12-ene-27a,28-dioic acid (quafrinoic acid)

Abstract

The title compound, C 30 H 44 O 5 , is a pentacyclic triterpene isolated from the Cameroonian medicinal plant Nauclea Pobeguinii and known as quafrinoic acid. The molecule is composed of five fused six-membered rings, four of which adopt a chair conformation and one a half-chair conformation. Intramolecular C-HÁ Á ÁO hydrogen-bond interactions exist, which generate S6 and S8 rings. In the crystal, molecules are linked by pairs of O-HÁ Á ÁO hydrogen bonds, linking R 2 2 (8) rings into chains running parallel to the a axis; these chains are further connected into layers parallel to the ab plane by C-HÁ Á ÁO hydrogen bonds. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from HÁ Á ÁH (79.4%) and OÁ Á ÁH (20.4%) interactions.