69142-64-9

23628-31-1

64-17-5

69142-64-9

6-Amino-2-pyridinecarboxylic acid (6.0 g, 43.5 mmol) was dissolved in ethanol (150 mL) at 0 °C and sulfoxide chloride (12.0 g, 101 mmol) was added slowly. The reaction mixture was heated to reflux with continuous stirring for 12 hours. Upon completion of the reaction, it was cooled to room temperature and the reaction mixture was subsequently concentrated under reduced pressure. The pH was adjusted to 9 with saturated aqueous sodium carbonate solution and concentrated again under reduced pressure. Dichloromethane (150 mL) was added to the residue, stirred vigorously for 30 minutes at room temperature and filtered. The filtrate was concentrated under reduced pressure to give ethyl 6-aminopyridine-2-carboxylate (5.5 g, 76% yield).