Synthesis and X‐ray crystal structure study of the hydroxyurea and hydantoin derivatives of l‐valine

Abstract: The novel hydroxyurea 5 derivative of L ‐valine was prepared by aminolysis of N‐(1‐benzotriazolecarbonyl)‐L ‐valine cyclohexanemethylamide 4 with hydroxylamine. The corresponding hydantoin derivative 6 was synthesized by base catalyzed cyclization of the amide 4 . The exact stereostructure of hydantoin derivative 6 has been determined by X‐ray crystal structure analysis. The chiral atom of the hydantoin ring in 6 has S configuration what is in agreement with its configuration in the starting L ‐valine. The molecules of 6 are joined into infinite chains by N–H?O intermolecular hydrogen bond. The infinite chains are additionally linked by two C–H?O hydrogen bonds, thus forming two‐dimensional network. The hydantoin derivative of L ‐valine 6 and its L ‐leucine analogue LH have similar packing arrangements, so they are homostructural.