反应详情

温度

130 °C

A mixture of 3-methyl-1-(2-pyridinyl)-1H-pyrazol-5-amine (1.8 g, 10 mmol) and polyphosphoric acid (4.2 g) was heated at 130° C. The mixture was stirred thoroughly at the same temperature, while ethyl acetoacetate (1.3 mL, 10 mmol) was added dropwise thereto, and the resulting mixture was stirred at the same temperature for 1 hour. The mixture was cooled to room temperature, iced water was added thereto. The mixture was neutralized with an aqueous sodium hydroxide solution, and organic matter was extracted with chloroform. The extract was washed with saturated brine and dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The residue thus obtained was purified by silica gel column chromatography (chloroform:methanol=50:1 to 20:1), and recrystallized from ethyl acetate to give the title compound (0.72 g, 30% yield).

1. additionwas added dropwise
2. temperatureThe mixture was cooled to room temperature
3. extractionwas extracted with chloroform
4. washThe extract was washed with saturated brine
5. dry with materialdried over anhydrous sodium sulfate
6. customthe solvent was evaporated under reduced pressure
7. customThe residue thus obtained
8. customwas purified by silica gel column chromatography (chloroform:methanol=50:1 to 20:1)
9. customrecrystallized from ethyl acetate