7418-65-7

7418-66-8

General procedure for the synthesis of 4-amino-3-carboxamido pyridine from 4-aminopyridine-3-carboxylic acid: To a stirring solution of 4-aminopyridine-3-carboxylic acid (3 g, 0.013 mol) in THF (50 mL) was added dropwise SOCl2 (3.6 mL, 0.045 mol) and a catalytic amount of DMF (30 μL) at room temperature and protected by argon gas. The reaction mixture was stirred until TLC showed complete consumption of the feedstock. Upon completion of the reaction, the volatiles were removed under reduced pressure to give the crude product. The crude product was dissolved in THF (30 mL) and cooled to 0 °C, followed by slow addition of 7N NH3-methanol solution (22 mL). The reaction mixture was gradually warmed to room temperature and stirring was continued for 4 hours. At the end of the reaction, the precipitate was collected by filtration and the filtrate was concentrated under reduced pressure to give the crude compound. The crude compound was purified by column chromatography (using 100-200 mesh silica gel, 60 g, eluent 10% MeOH-10% NH4OH/DCM) to give 4-amino-3-carboxamido pyridine (475 mg, 27% yield), which was used in the next step of the reaction without further purification.LCMS (ESI+): m/z: 138.33 [M + H]+.