反应详情

2.0 g of O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphine (5.2 mmol) were added to 1.0 g of 5,6-dichloronicotinic acid (5.2 mmol) dissolved in 2.4 mL of tetrahydrofuran and 2.5 mL of dimethylformamide, and stirred at room temperature for 10 minutes. 2.6 mL of ethylamine in 2.0 M tetrahydrofuran solution (5.2 mmol) was added thereto, and refluxed under heating and stirring for 18 hours. The mixture was cooled to room temperature, concentrated under reduced pressure to be dissolved in ethyl acetate, and washed with water. The organic layer was dried over magnesium sulfate, and concentrated under reduced pressure. The residue was separated by column chromatography (eluting solvent: chloroform/methanol=20/1) to obtain 0.8 g of 5,6-dichloro-N-ethyl-nicotinamide (yield 70%).

1. temperaturerefluxed
2. temperatureunder heating
3. concentrationconcentrated under reduced pressure
4. dissolutionto be dissolved in ethyl acetate
5. washwashed with water
6. dry with materialThe organic layer was dried over magnesium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe residue was separated by column chromatography (eluting solvent: chloroform/methanol=20/1)