| Title:  L-2-Oxo-4-thiazolidinecarboxylic acid CAS Registry Number:  19771-63-2 CAS Name:  (4R)-2-Oxo-4-thiazolidinecarboxylic acid Additional Names:  OTCA;  OTC Trademarks:  Procysteine (Baxter) Molecular Formula:  C4H5NO3S Molecular Weight:  147.15 Percent Composition:  C 32.65%, H 3.42%, N 9.52%, O 32.62%, S 21.79% Literature References:  Cysteine prodrug.  Prepn:  J. A. Maclaren, Aust. J. Chem. 21, 1891 (1968); T. Kömives, Org. Prep. Proced. Int. 21, 251 (1989).  Crystal structure:  N. Ramasubbu, R. Parthasarathy, Int. J. Pept. Protein Res. 34, 153 (1989).  Precursor for cysteine and use as glutathione biosynthesis stimulant:  J. M. Williamson et al., Proc. Natl. Acad. Sci. USA 79, 6246 (1982); in chicks:  T. K. Chung et al., J. Nutr. 120, 158 (1990).  Toxicity:  R. D. White et al., Acute Toxic. Data 1, 164 (1992); R. D. White et al., Toxicol. Lett. 69, 15 (1993).  Clinical evaluation in HIV infection:  G. Giorgi et al., Curr. Ther. Res. 52, 461 (1992); in asymptomatic HIV infection:  R. C. Kalayjian et al., J. Acquired Immune Defic. Syndr. 7, 369 (1994).  HPLC determn in plasma:  L. W. Webb et al., J. Chromatogr. B 654, 257 (1994). Properties:  Colorless cubes, mp 171-173° (dec) (Maclaren).  Also reported as white crystals, mp 173-174° (Kömives).  pKa (22°):  3.32.  [a]D20 -59.4° (c = 2).  Readily sol in alcohol.  Insol in benzene and ethyl acetate. Melting point:  mp 171-173° (dec) (Maclaren); mp 173-174° (Kömives) pKa:  pKa (22°):  3.32 Optical Rotation:  [a]D20 -59.4° (c = 2)  |