反应详情

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 1 N 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.

1. customThe solvent was removed
2. additionthe residue was diluted with ethyl acetate
3. extractionThis organic phase was extracted with 1 N lithium chloride (LiCl), water, and brine
4. dry with materialdried over calcium sulfate
5. concentrationconcentrated
6. customchromatographed on silica gel (2.75×4 inches) with elution proceeding
7. custom20% ethyl acetate/hexane (500 mL), unweighed recovered o-toluidine