Infrared and Raman spectra (4000–100 cm−1) of solid samples of six different methyl substituted thiazolidine products of D-penicillamine and L-cysteine hydrochloride have been observed and assigned. Infrared spectra in D2O solutions have been obtained for comparison in order to study the amino-acid zwitterion equilibria. Proton and 13C nmr spectra for the compounds have also been measured.

No abstract

The X-ray crystal structure of (S)-2,2,5,5-tetramethylthiazolidine-4-caboxyic acid, b, has been determined. Crystals are monoclinic, P 2 , , with cell dimensions a = 11.351(4) b = 8.303(2), c = 11.969(3) A, P = 116.69(2)", and Z = 4. The structure was solved by standard methods and refined to RI = 0.0774, R2 = 0.0670 for 2388 independent reflections.Compound 1 exists in the amino-acid form as shown by two distinctly different C-0 bond lengths, 1.209 and 1.309 A, typical of the COOH group, and by the positions of the hydrogen atoms. The amino-acid form of 1 found in the solid also exists in solution as shown by infrared and Raman spectra. ' The mass spectra, and 'H and "C nmr spectra are reported, as well as detailed infrared and Raman spectra for the title compound and several deuterated species. [Traduit par le journal]

127 (1984). The compound dipotassium 3,3,3',3'-tetramethylcystinate trihydrate, K2 [CII,H,,0,N2S2]3H20, has been prepared and characterized by single crystal X-ray diffraction. Crystals were monoclinic, P 2 , , n = 6.160(1), b = 26.473(8), c = 6.193(1) A, P = 113.94(1)", with two formula units in the unit cell. Intensities were measured on a Syntex P2[ diffractometer with use of MoKa radiation. The structure was solved by standard methods and refined to RI = 0.0469, R2 = 0.0472 based on 2303 independent observed reflections. The C-S bonds (1.877(6), 1.891(6) A) are longer than in many similar compounds although the S-S bond (2.040(2) A) is not. The C-S-S-C torsional angle (108.7(3)") is larger than normal in dithiol compounds. Other distances and angles are normal. Two types of potassium coordination are present, one a distorted octahedron, the other a distorted trigonal prism. In addition to the ionic interactions, hydrogen bonds involving the water molecules are important in stabilizing the structure. (108,7(3)") est plus grand que ceux observts normalement dans les dithiols. Les autres distances et les autres angles sont normaux. Le potassium posskde deux types de coordination, I'un est un octakdre deform6 tandis que I'autre est un prisme trigonal dCformC. En plus des interactions ioniques, les liaisons hydrogknes impliquant les molCcules d'eau sont importantes pour de la stabilitC de la structure.[Traduit par le journal]