2-Pyrazinecarboxylic acid → N-[2-amino-2,2-bis(4-fluorophenyl)-1-methylethyl]-2-pyrazinecarboxamide

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Reaction Steps

1,1-bis(4-fluorophenyl)-1,2-propanediamine (94 mg) and pyrazinecarboxylic acid (53 mg) was dissolved in pyridine (1 mL), and to the solution was added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (103 mg). The mixture was stirred at room temperature for 24 hrs. The reaction mixture was concentrated, and the obtained residue was dissolved in chloroform, followed by washing with saturated sodium hydrogen carbonate aqueous solution. The aqueous layer was extracted with chloroform twice, and the combined chloroform layers were dried over magnesium sulfate. After evaporating the solvent in vacuo, the obtained residue was purified by silica gel column chromatography (C-300; hexane: ethyl acetate=1:1→1:3) to give N-[2-amino-2,2-bis(4-fluorophenyl)-1-methylethyl]-2-pyrazinecarboxamide (112 mg) as the mixture with pyrazinecarboxylic acid methyl ester. The mixture was dissolved in methanol (1 mL), and to the solution was added 2N sodium hydroxide aqueous solution (0.5 mL), and the solution was stirred at room temperature for one hr. The reaction mixture was diluted with chloroform, followed by washing with water. The aqueous layer was extracted with chloroform twice, and the combined chloroform layers were dried over anhydrous magnesium sulfate. The solvent was evaporated in vacuo to give the pure amide compound (95 mg).

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