Hydrochloric Acid → Methyl 6-amino-3-methoxy-2-pyrazinecarboxylate

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Reaction Conditions

Reaction Steps

In a nitrogen atmosphere, 11.38 g of methyl 6-bromo-3-methoxy-2-pyrazinecarboxylate is dissolved in 227 mL of toluene. To the solution are successively added 10.32 g of benzophenone-imine, 0.42 g of tris(dibenzylideneacetone) dipalladium, 0.86 g of (s)-(−)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl and 6.20 g of sodium t-butoxide. The resulting mixture is stirred at 80° C. for one hour. The reaction mixture is cooled and filtered. The filtrate is purified by column chromatography (eluent: toluene:ethyl acetate=20:1). The oily product thus obtained is dissolved in 140 mL of tetrahydrofuran, 7 mL of 2 mol/mL hydrochloric acid is added thereto and the resulting solution is stirred at ambient temperature for 15 minutes. A mixture of 200 mL of chloroform and 50 mL of water is added to the resulting reaction mixture, and alkalified with 1 mol/mL of sodium hydroxide, and the organic layer is separated. The organic layer is washed with saturated aqueous solution of sodium chloride, dried over anhydrous magnesium sulfate, and the solvent is distilled off under reduced pressure. The residue thus obtained is purified by column chromatography (eluent: toluene:ethyl acetate 1:1) to obtain 3.64 g of methyl 6-amino-3-methoxy-2-pyrazinecarboxylate.

Provenance & Evidence