The crystal structure of a new polymorph of 1-acetyl-2-thiohydantoin has been determined by X-ray diffraction. The crystal, C5H6N2O2S, belongs to space group P1 with cell dimensions of a = 4.9865(7)Å, b = 5.5716(7)Å, c = 12.544(2)Å, α = 74.793(8)°, β = 80.413(9)°, γ = 85.001(10)°. The final R1 value is 0.036 for 1304 reflections (I > 2.0σ(I)). In the new polymorph, intermolecular hydrogen bonds are formed between the acetyl C=O and the amide N-H groups [N(1)…O(2)(i) 2.800(2)Å, N(1)-H…O(2)(i) 151.02°, symmetry codes: (i) x+1, y-1, z] to form an infinite chain structure. On the other hand, the hydrogen bonds in the known form are formed between the amide C=O and the amide N-H groups of the thiohydantoin rings.
2009 by The Japan Society for Analytical Chemistry