反应详情

To ethyl 4-bromo-3-methyl-1H-pyrazole-5-carboxylate (2.56 g, 10.98 mmol) in DMF (30 mL) were added Cs2CO3 (8.94 g, 27.4 mmol) and 4-(chloromethyl)-1-methyl-1H-pyrazole, HCl (2.2 g, 13.17 mmol). The reaction mixture was stirred at room temperature for 20 hours and then diluted with water. The product was extracted into EtOAc. The organic phase was dried over Na2SO4 and concentrated. The crude residue was purified by CombiFlash® chromatography (120 g, column) eluting with a gradient of 10-100% EtOAc in heptane over a period of 180 minutes. The product-containing fractions were combined and concentrated to give the title compound (0.82 g, 23%) and a regioisomer, ethyl 4-bromo-5-methyl-1-((1-methyl-1H-pyrazol-4-yl)methyl)-1H-pyrazole-3-carboxylate (1.32 g, 36.8%).

1. extractionThe product was extracted into EtOAc
2. dry with materialThe organic phase was dried over Na2SO4
3. concentrationconcentrated
4. customThe crude residue was purified by CombiFlash® chromatography (120 g, column)
5. washeluting with a gradient of 10-100% EtOAc in heptane over a period of 180 minutes
6. concentrationconcentrated