Crystal Structures of Chiral and Racemic 4-Methyl-5-phenyl-1,3-oxazolidine-2-thione

Abstract

(4S,5R)- and (rac)-4-Methyl-5-phenyl-1,3-oxazolidine-2-thione (MPOT) crystallize in the orthorhombic P2₁2₁2 and monoclinic C2/c, respectively, with eight molecules in a unit cell. In (rac)-MPOT crystals, the thioamide groups of the enantiomeric (4S,5R)- and (4R,5S)-MPOT pairs are hydrogen-bonded around a center of symmetry to form a planar cyclic dimer. On the other hand, a cyclic dimer through the hydrogen bonding is formed between the two independent molecules (molecules A and B) and its geometry is considerably distorted in (4S,5R)-MPOT crystals.