CAS No 95-25-0 , 5-chloro-3H-1,3-benzoxazol-2-one

Title: Chlorzoxazone
CAS Registry Number: 95-25-0
CAS Name: 5-Chloro-2(3H)-benzoxazolone
Synonyms: 5-chloro-2-benzoxazolol; 5-chloro-2-hydroxybenzoxazole; 2-hydroxy-5-chlorobenzoxazole; 5-chlorbenzoxazolin-2-one; 5-chlorobenzoxazolidone
Trademarks: Paraflex (McNeil); Biomioran; Solaxin
Molecular Formula: C7H4ClNO2
Molecular Weight: 169.57
Percent Composition: C 49.58%, H 2.38%, Cl 20.91%, N 8.26%, O 18.87%
Literature References: Prepn from 2-amino-5-chlorobenzoxazole: Marsh, US 2895877 (1959 to McNeil Labs.). LC determn in plasma: I. L. Honigsberg et al., J. Pharm. Sci. 68, 253 (1979). Fluorometric determn in tablets and biological fluids: J. T. Stewart, C. W. Chan, ibid. 910. Clinical studies: R. Herman, Curr. Ther. Res. 9, 537 (1967); J. J. Scheiner, ibid. 19, 51 (1976). Metabolism study: R. Twele, G. Spiteller, Arzneim.-Forsch. 32, 759 (1982). Toxicity: G. Hofrichter et al., Arzneim.-Forsch. 17, 242 (1967). Review of clinical studies: J. K. Elenbaas, Am. J. Hosp. Pharm. 37, 1313 (1980). Comprehensive description: J. T. Stewart, C. A. Janicki, Anal. Profiles Drug Subs. 16, 119-144 (1987).
Properties: Crystals from acetone, mp 191-191.5°. Sparingly sol in water; sol in methanol, ethanol, isopropanol. Freely sol in aq solns of alkali hydroxides and ammonia. LD50 in mice (mg/kg): 3650 orally, 380 i.p. (suspensions); 440 orally, 183 i.p. (solns of Na salt) (Hofrichter).
Melting point: mp 191-191.5°
Toxicity data: LD50 in mice (mg/kg): 3650 orally, 380 i.p. (suspensions); 440 orally, 183 i.p. (solns of Na salt) (Hofrichter)
Therap-Cat: Muscle relaxant (skeletal).
Keywords: Muscle Relaxant (Skeletal).