Crystal structure and Hirshfeld surface analysis of 3-acetyl-11-keto-β-boswellic acid.

Acetyl-11-keto-β-boswellic acid, C32H48O5, a penta-cyclic triterpenoid from Boswellia serrata, exhibits notable anti-inflammatory and pharmacological activities. The compound crystallizes in the ortho-rhom-bic space group P21212 and exhibits a rigid penta-cyclic framework with eleven stereogenic centers. The cyclo-hexane rings adopt near-ideal chair conformations with minimal steric strain. The crystal packing is governed by O-H⋯O hydrogen bonds, forming zigzag chains along the [100] direction and extending into a three-dimensional network and is further consolidated by van der Waals inter-actions. Hirshfeld surface analysis shows dominant H⋯H contacts (91.5%), highlighting the importance of van der Waals forces, while H⋯O/O⋯H contacts provide localized stabilization.