Dichloromethane → 5-Amino-6-(4-fluoro-phenyl)-pyrazine-2-carboxylic acid methyl ester

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Reaction Steps

To a methanol solution (35 ml) of 5-bromo-3-(4-fluoro-phenyl)-pyrazin-2-ylamine (1.87 g, 6.97 mmol, 1.0 eq) was added 15 ml ethyl acetate at room temperature. [1,1′-bis(diphenylphosphino)ferrocen]palladium(II)chloride 1:1 complex with dichloromethane (0.26 g, 0.32 mmol, 0.05 eq) was added portion-wise to the reaction mixture followed by triethylamine (1.95 ml, 13.5 mmol, 2.0 eq) and the solution was heated with stirring to 110° C. under 70 bar carbon monoxide for 18 hours. On cooling and removal of carbon monoxide, the reaction mixture was concentrated in vacuo and the residue purified by chromatography on silica gel with heptane:ethyl acetate (1:1) to afford 5-Amino-6-(4-fluoro-phenyl)-pyrazine-2-carboxylic acid methyl ester as white crystals. Yield=1.26 g (73%). 1H-NMR (400 MHz, DMSO): δ 3.80 (3H, s), 7.11 (2H, br s), 7.33 (2H, t, J=8.87 Hz), 7.67-7.70 (2H, m), 8.56 (1H, s). HPLC-MS=100%; 1.49 min (MW=247; M+1=248.3).

Provenance & Evidence