CAS No 490-79-9 , 2,5-dihydroxybenzoic acid

Title: Gentisic Acid
CAS Registry Number: 490-79-9
CAS Name: 2,5-Dihydroxybenzoic acid
Synonyms: 5-hydroxysalicylic acid
Molecular Formula: C7H6O4
Molecular Weight: 154.12
Percent Composition: C 54.55%, H 3.92%, O 41.52%
Literature References: Occurs in gentian: Redgrove, Pharm. J. 122, 324 (1929). Found in urine of dogs after ingestion of salicylates: Neuberg, Berl. Klin. Wochenschr. 48, 799 (1911). Prepd from hydroquinone: Senhofer, Sarlay, Monatsh. Chem. 2, 448 (1881); Juch, ibid. 26, 839 (1905); Brunner, Ann. 351, 321 (1907); Zeltner, Landau, DE 258887; Frdl. 11, 210; Dyson, Manual of Organic Chemistry vol. I (London, 1950) p 614; by oxidation of salicylic acid with potassium persulfate: DE 81297 (to Schering AG); Frdl. 4, 127; from p-hydroxyphenol: Meyer, US 2588336 (1952 to Monsanto); from 5-bromo-2-hydroxybenzoic acid: Lowenthal, Pepper, J. Am. Chem. Soc. 72, 3292 (1950); by Kolbe synthesis: Clemens, US 2816137 (1957 to Eastman Kodak). Metabolic product of Penicillium patulum: Tanenbaum, Bassett, Biochim. Biophys. Acta 28, 21 (1958); of Polyporus tumulosus Cooke: Crowden, Ralph, Aust. J. Chem. 14, 475 (1961). Biosynthesis: Gatenback, Linnroth, Acta Chem. Scand. 16, 2298 (1962).
Properties: Needles, monoclinic prisms from water, mp 199-200°. Crystals are dimorphic and undergo phase inversion upon heating. The stable phase begins to sublime at 200° and melts at 205°. pK (25°): 2.93. Sol in water (about 1 part in 200 parts H2O at 5°, much more sol in hot water), alcohol, ether. Practically insol in carbon disulfide, chloroform, benzene.
Melting point: mp 199-200°
pKa: pK (25°): 2.93
 
Derivative Type: Sodium salt
CAS Registry Number: 4955-90-2
Synonyms: Sodium gentisate
Trademarks: Gentinatre; Gentisod; Legential; Gentisine U.C.B
Molecular Formula: C7H5NaO4
Molecular Weight: 176.10
Percent Composition: C 47.74%, H 2.86%, Na 13.05%, O 36.34%
Properties: Crystals with 5?H2O from water. Rapidly loses 3H2O on exposure to air, but holds ?H2O tenaciously even at 100°. Sol in water.
 
Therap-Cat: Analgesic; anti-inflammatory.
Keywords: Analgesic (Non-Narcotic); Anti-inflammatory (Nonsteroidal); Salicylic Acid Derivatives.