73672-37-4

626-55-1

109-72-8

95-92-1

73672-37-4

3-Bromopyridine (25.7 g) was dissolved in ether (400 ml) under nitrogen protection and cooled to -78°C. At this temperature, n-butyllithium (1.6N hexane solution, 108 ml) was slowly added dropwise over a period of 1 hour. After the dropwise addition, stirring was continued for 30 minutes. Subsequently, an ether solution (100 ml) of diethyl oxalate (28.6 g) was added slowly dropwise over a period of 1 hour at -78°C. After completion of the dropwise addition, stirring was continued for 30 min and then the reaction mixture was allowed to slowly warm up to 0°C. 1N hydrochloric acid (200 ml) was added and stirred for 30 minutes. The reaction mixture was neutralized with sodium bicarbonate and the organic layer was separated. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate and concentrated. The residue was purified by silica gel column chromatography to afford ethyl 3-pyridylglyoxylate (13.1 g, 45% yield) using ethyl acetate-hexane (1:1, v/v) as eluent.