Crystallographic Analysis of Acetyl β ‐boswellic acid

The crystal structure of the title compound (3α-acetoxy-urs-12-en-24-oic acid, C 32 H 50 O 4 ) has been determined by X-ray crystallographic techniques. The compound crystallizes into orthorhombic space group P2 1 2 1 2 with unit cell parameters: a = 12.773(2), b=16.381(4), c=27.929(7)A. The structure has been solved by direct methods and refined to R = 0.054 for 4930 observed reflections. The structure contains two crystallographically independent molecules in the asymmetric unit which are almost identical in geometry. Rings A, B, D and E have chair conformations while ring C assumes a sofa conformation in both the molecules. The molecules in the structure are linked together by intra- and intermolecular O-H…O and C-H…O hydrogen bonds.