Synthesis and crystal structure of (S)-5-isopropyl-5-methyl-2-thiohydantoin

Abstract

(S)-5-Isopropyl-5-methyl-2-thiohydantoin was synthesized by one-pot reaction of α-methyl-L-valine and thiourea in the absence of solvent. The crystal structure of this compound has been determined from single crystal X-ray diffraction data. This is the first report on the crystal structure of a homochiral 5-substituted 2-thiohydantoin with the unsubstituted NH groups. This compound, C₇H₁₂N₂OS crystallizes in the chiral orthorhombic space group P2₁2₁2₁ with four molecules in the unit cell. The unit cell parameters are: a = 8.2798(12) Å, b = 8.6024(13) Å, c = 12.826(2) Å and V = 913.6(2) ų. In the crystals, the thioamide and amide N-H of one molecule are hydrogen-bonded to the thioamide C=S group of neighboring molecules to form rings with the R²₂(8) graph-set motif, and these rings are linked into infinite one-dimensional tapes.