Crystal structure of lubiprostone Polymorph B, C20H32F2O5

Abstract

The crystal structure of lubiprostone has been refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Lubiprostone crystallizes in space group P1 (#1) with a = 9.02025(2), b = 10.72121(2), c = 12.32817(4) Å, α = 78.5566(2), β = 69.6858(2), γ = 77.3292(2)°, V = 1081.069(3) Å3, and Z = 2. The two independent molecules occur in an extended conformation, aligned approximately along the c-axis. The hydrophobic side chains are adjacent to each other, resulting in layers parallel to the ac plane. The two carboxylic acid groups form an eight-membered ring, resulting in dimers of the two independent molecules. Each hydroxyl group acts as a hydrogen bond donor to the ketone of the fused ring system. The powder pattern is included in the Powder Diffraction File™ as entry 00-066-1622.