Cesium carbonate → 3-Amino-5-bromo-1-methyl-1,2-dihydropyridin-2-one

Participants

Reaction Conditions

Reaction Steps

A 48-mL sealed tube equipped with a magnetic stirring bar was charged with benzophenone imine (0.43 g, 2.4 mmol), 3,5-dibromo-1-methyl-1H-pyridin-2-one (1) (0.51 g, 2.0 mmol), Pd(OAc)2 (0.025 g, 0.040 mmol), rac-BINAP (0.082 g, 0.13 mmol), and Cs2CO3 (0.92 g, 2.8 mmol) in dioxane (15 mL). After the mixture was degassed for 15 min., it was heated at 95° C. for 16 h. Then, the reaction mixture was cooled to room temperature and poured into H2O (10 mL). To this was added dichloromethane and the layers were separated. The aqueous phase was extracted with dichloromethane (3×10 mL), and the combined organic extracts were washed with H2O (5 mL) and brine (5 mL), dried (Na2SO4), and concentrated. The crude product was dissolved in 1 N HCl/MeOH (3 mL) and stirred for 1 h at room temperature. Then, to the reaction mixture was added sat. NaHCO3 (10 mL) and dichloromethane (10 mL), and the phases were separated. The aqueous layer was extracted with dichloromethane, and the combined organic layers were washed with H2O (5 mL) and brine (5 mL), dried (Na2SO4), and concentrated. The crude mixture was purified by column chromatography, gradient 0-10% MeOH in dichloromethane/ether (1/1), to afford 0.22 g (54%) of 3-amino-5-bromo-1-methyl-1H-pyridin-2-one (4) as a solid.

Provenance & Evidence