1H-Pyrrolo[2,3-c]pyridine-2-carboxylic acid ethyl ester

95-92-1

180253-66-1

24334-19-8

1. tert-Butyl (4-methylpyridin-3-yl)carbamate (3.5 g, 16.8 mmol) was dissolved in anhydrous THF (30 ml) and cooled to -40 °C under argon protection. 2. tert-butyl lithium (20.7 ml, 1.7 M pentane solution, 35.2 mmol) was added slowly and the reaction mixture was kept stirred at -40 °C for 1 hour. 3. A solution of diethyl oxalate (2.5 ml, 18.5 mmol) in THF (30 ml) was added dropwise over 15 min. 4. the reaction mixture was warmed to 0 °C and stirring was continued for 2 h. The reaction mixture was then slowly warmed to room temperature and stirred for 19 h. The reaction mixture was then stirred for 1 h. The reaction mixture was then slowly warmed to room temperature. 5. 2N HCl (110 ml) was carefully added to the reaction mixture and heated to reflux for 2 hours. 6. After cooling, the organic phase was extracted by adding dichloromethane (100 ml) and the aqueous phase pH was adjusted to 8 and the organic phase was separated. 7. The aqueous phase was washed with dichloromethane (2 x 50 ml), the organic layers were combined, dried with magnesium sulfate and concentrated to give a light brown solid. 8. The solid was ground with ethyl acetate and the beige solid product (586 mg, 18%) was collected by filtration. LCMS (Method B): RT = 1.89min, M + H + = 190.