O-Toluidine → 3-Aminopyrazine-2carboxylic acid o-toluamide

Beteiligte Stoffe

Reaktionsschritte

A mixture of 3-aminopyrazine carboxylic acid (5.0 g, 35.94 mmol), methylene chloride (110 mL), 4-dimethylaminopyridine (10.98 g, 89.85 mmol), o-toluidine (4.22 mL, 39.53 mmol), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (8.27 g, 43.13 mmol) was stirred overnight at ambient temperature. The solvent was removed and the residue was diluted with ethyl acetate. This organic phase was extracted with 1N lithium chloride (LiCl), water, and brine, dried over calcium sulfate and concentrated. The residue was flash chromatographed on silica gel (2.75×4 inches) with elution proceeding as follows: hexane (300 mL), nil; 20% ethyl acetate/hexane (500 mL), unweighed recovered o-toluidine; 20% ethyl acetate/hexane (1000 mL) and 30% ethyl acetate/hexane (2000 mL), 4.79 g (58%) of 3-aminopyrazine-2-carboxylic acid o-toluamide as a yellow crystalline solid.

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