Cesium carbonate → Methyl [5-(4-ethylphenyl)pyridin-3-yl]carbamate

Participants

Reaction Conditions

Reaction Steps

Under argon and at RT, a solution of 16.8 g (64 mmol) of 3-bromo-5-(4-ethylphenyl)pyridine in 70 ml of dioxane was added to a suspension of 555 mg (0.96 mmol, 0.015 eq.) of Xantphos (4,5-bis(diphenylphosphino)-9,9′-dimethylxanthene), 293 mg (0.32 mmol, 0.005 eq.) of tris(dibenzylideneacetone)dipalladium, 29.1 g (89 mmol, 1.4 eq.) of caesium carbonate and 5.8 g (77 mmol, 1.2 eq.) of methyl carbamate in 100 ml of dioxane. The reaction mixture was stirred at 90° C. for 20 h. Since the progress of the reaction was slow, a little at a time, three times in total, 555 mg (0.96 mmol, 0.015 eq.) of Xantphos and 293 mg (0.32 mmol, 0.005 eq.) of tris(dibenzylideneacetone)dipalladium were added to the reaction mixture, and in each case the mixture was stirred at 90° C. overnight. After addition of dichloromethane, the reaction mixture was filtered through Celite and the filtrate was concentrated under reduced pressure. The crude product was stirred with acetonitrile and the residue that remained was repeatedly washed with cold acetonitrile and dried under reduced pressure. Yield: 15 g (90% of theory)

Provenance & Evidence