The crystal structure of etrasimod has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Etrasimod crystallizes in space group P1 (#1) with a = 10.6131(5), b = 10.7003(5), c = 11.1219(8) Å, α = 72.756(2), β = 76.947(2), γ = 77.340(1)°, V = 1159.28(6) Å3, and Z = 2 at 298 K. The crystal structure contains O▬H⋯O hydrogen-bonded etrasimod dimers, which lie in layers approximately parallel to the (2,0,−1) plane. The amino group of each molecule forms an intramolecular N▬H⋯O hydrogen bond to the carbonyl group of the adjacent carboxylic acid group. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).
