Abstract
The chemical and stereochemical structure of lenthionine has been established by the X-ray method. Lenthionine crystallizes in the monoclinic system, space group P21/a-C52h, with four molecules of S5 (CH2)2 in the unit cell. Using a three-dimensional Patterson function and minimum functions, all atomic positions were determined. The least squares method was adopted to distinguish CH2 groups from sulfur by the temperature factors. Thus the three-dimensional molecular geometry has been elucidated to be in a chair form, having C2 pseudo-symmetry.