Potassium Phosphate, Tribasic → Methyl 6-(6,7-dimethoxyquinolin-4-yloxy)benzofuran-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

Methyl 6-hydroxybenzofuran-3-carboxylate (312 mg, 1.62 mmol) was dissolved in N,N-dimethylformamide (5 mL) then added 4-chloro-6,7-dimethoxyquinoline (451 mg, 2.02 mmol), 2-(dicyclohexylphosphino)-2′,4′,6′-triisopropyl-1,1′-biphenyl (77 mg, 0.162 mmol), palladium acetate (36 mg, 0.162 mmol) and potassium phosphate (687 mg, 3.24 mmol). The reaction mixture was stirred at 100° C. overnight. Additional palladium acetate (36 mg, 0.162 mmol) was added to the mixture and the heating was continued at 100° C. for 4 h. Additional 4-chloro-6,7-dimethoxyquinoline (181 mg, 0.812 mmol) and 2-(dicyclohexylphosphino)-2′,4′,6′-triisopropyl-1,1′-biphenyl (77 mg, 0.162 mmol) were added to the mixture and heating at 100° C. was continued for 2 days. The reaction mixture was filtered and the filtrate was concentrated in vacuo. The remaining orange oil was redissolved in toluene (5 mL) and DMF (1 mL) then added 4-chloro-6,7-dimethoxyquinoline (225 mg, 1.01 mmol), 2-(dicyclohexylphosphino)-2′,4′,6′-triisopropyl-1,1′-biphenyl (38 mg, 0.080 mmol), palladium acetate (18 mg, 0.080 mmol) and potassium phosphate (343 mg, 1.62 mmol). The reaction mixture was heated at 100° C. overnight and concentrated in vacuo. The remaining orange-black oil was purified by silica gel chromatography (1% to 2% methanol in dichloromethane) to afford methyl 6-(6,7-dimethoxyquinolin-4-yloxy)benzofuran-3-carboxylate as a light yellow solid. MS (ESI, pos. ion) m/z: 380.1 (M+1).

Provenance & Evidence