反应详情

3,5-Dibromo-1H-pyrazole-4-carbaldehyde (987.9 mg, 3.89 mmol) and potassium carbonate (1.613 g, 11.67 mmol) were dissolved in N,N-dimethylformamide (39 mL) at 25° C. under Ar. 4-methoxybenzyl bromide (617 μl, 4.28 mmol) was added dropwise. The reaction mixture was allowed to stir for 2 h 10 min. The reaction was stopped, quenched by addition of saturated aqueous ammonium chloride (30 mL), and the mixture extracted with ethyl acetate (3×30 mL). The combined organic phases were washed with saturated aqueous sodium chloride (1×20 mL), dried (sodium sulfate), filtered, and the solvent evaporated under reduced pressure. The crude product was purified by flash chromatography (RediSep SiO2, 120 g column) on a CombiFlash Rf purification system eluting with ethyl acetate-hexanes (0-55%). The title compound (L3342 g, 3.57 mmol, 92% yield) was recovered as a colorless, very viscous oil. LC-MS [M+1]=373.1.

1. customquenched by addition of saturated aqueous ammonium chloride (30 mL)
2. extractionthe mixture extracted with ethyl acetate (3×30 mL)
3. washThe combined organic phases were washed with saturated aqueous sodium chloride (1×20 mL)
4. dry with materialdried (sodium sulfate)
5. filtrationfiltered
6. customthe solvent evaporated under reduced pressure
7. customThe crude product was purified by flash chromatography (RediSep SiO2, 120 g column) on a CombiFlash Rf purification system
8. washeluting with ethyl acetate-hexanes (0-55%)