4-Pyridylmercaptoacetic acid: 600-m1 of sodium hydroxide (88, 4, 9, 2, 21 mol) and water were placed in an EndPage:3 flask equipped with a condenser. 80-Mercaptoacetic acid (76, 79, 0, 67 mol) was added with stirring, followed by 4-chloropyridine hydrochloride (100 g, 0.67 mol). The mixture was heated under stirring at reflux temperature for 4 hours. About 5 g of cooled decolorized carbon was added to the resulting solution at 80C. Stirring was continued for 5 min and then filtered using a filter aid. The r solution was acidified to pH 4.5 by the addition of acetic acid. the resulting slurry was cooled to 5 C and filtered to collect. 100 ml of solid! Wash Dissolve the wet filter cake in 6 NHC, 200 m,g and 500 ml of water. The clear solution was about 200 ml of 10% sodium hydroxide! Neutralize to pH 5. The slurry is cooled to 5C, collected on a filter and washed with 200 ml of water. The solid was then washed with isopropanol 100rrLe. The product, 4-pyridylmercaptoacetic acid, was dried at 50 C at room temperature to give about 829 (73). Melting point 267-268C (decomposition). Literature value: mp270°C.
