Hydrochloric Acid → HCID 178431739, compound

Participants

Reaction Steps

A mixture of 5-chloroisatin acetamide (IV, 5.00 g), potassium hydroxide (1 N, 56 ml) and THF (18 ml) is heated at reflux for 1 hr, allowing the THF to boil off, and is allowed to cool to 20-25°. The basic mixture is cooled to 0° and acidified to pH 5.5 (pH paper) with hydrochloric acid (4 N). The resulting solids are filtered, washed with water and methylene chloride, dried, and triturated overnight in methylene chloride (200 ml, to remove a small amount of 5-chloroisatin byproduct). These solids are filtered, washed with methylene chloride, and dried to give 6-chloro-2-hydroxyquinoline-4-carboxylic acid (V), mp >3000; IR (mineral oil) 1711, 1645, 1430, 1221, 1179, 887 and 881 cm-1 ; NMR (d6 -DMSO) 12.25, 8.30, 7.62, 7.38 and 7.00 δ; MS (EI, m/e) 223, 178 and 151.

Provenance & Evidence