Detail of "86-47-5"

Reference

Process for producing isomer-free 7-chloro-4-hydroxyquinoline

Process for producing isomer-free 7-chloro-4-hydroxyquinoline. Mester, Tamas; Kortvelyessy, Gyula; Kortvelyessi, Gyula, Mrs.; Kalman, Gyorgy; Puskas, Attila; Szatmari, Antal; Varga, Gabor; Visy, Andras; Repasi, Janos; et al. (Alkaloida Vegyeszeti Gyar, Hung.). Hung. Teljes HU 57730 A2 30 Dec 1991, 12 pp. (Hungary). CODEN: HUXXBU. CLASS: ICM: C07D215-16. APPLICATION: HU 90-3314 4 May 1990. DOCUMENT TYPE: Patent CA Section: 27 (Heterocyclic Compounds (One Hetero Atom)) Section cross-reference(s): 63 Condensation reaction of 3-ClC6H4NH2 with the system [CH2(CO2R)2 + HC(OR')3] (R = Me; R' = Me, Et) in the presence of Mg salts or metallic Mg and/or anilinium or ammonium catalysts afforded 3-ClC6H4NHCH:C(CO2R)2 (I; R = Me) in up to 94% yield. Regioselective thermal cyclization of I (R = Me) in inert org. solvent at 180-280° afforded quinoline-3-carboxylate II (R = Me) with only 2-3% 5-Cl isomer impurity; hydrolysis and decarboxylation afforded 4-hydroxy-7-chloroquinoline with 2-2.5% 5-Cl isomer impurity. Regiononselectivity (i. 86-47-5 and 140646-26-0 are cas registry numbers of chemicals which are used as reagents here.e., 5-Cl isomer content) increased in the series R = Me < Et < iso-Pr. Condensation of 18.75 g 3-ClC6H4NH2, 23.3 g HC(OEt)3, and 36.7 g CH2(CO2Me)2 in presence of 0.04 g Mg and 0.21 g NH4Cl afforded 99% I (R = Me); the latter underwent cyclization at 235-245° for 1 h in diesel fuel, with subsequent hydrolysis/decarboxylation ultimately affording 21.25 g 7-chloro-4-hydroxyquinoline of above-stated purity. .