Potassium Carbonate → ethyl 3-methylquinoxaline-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

A suspension of 3-chloroquinoxaline-2-carboxylate (86.0 g, 363 mmol), trimethylboroxine (22.8 g, 0.182 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (8.90 g, 11.0 mmol), and potassium carbonate (100 g, 727 mmol) in 1,4-dioxane (726 mL) was heated at 115° C. for 4 h. And then trimethylboroxine (22.8 g, 0.182 mmol) was added again and heated at same temperature for 2 h. After being cooled to ambient temperature, the reaction mixture was diluted with ethyl acetate (700 mL) and filtrated through celite with ethyl acetate (1000 mL). The filtrate was combined and concentrated in vacuo. The residue was purified by silica gel column chromatography (silica gel 900 g, hexane:ethyl acetate=9:1 to 17:3) followed by recrystallization from cold hexane to give ethyl 3-methylquinoxaline-2-carboxylate. MS (APCI): m/z 217 (M+H).

Provenance & Evidence