反应详情

To a 40% aqueous solution of glyoxal (8.28 g, 6.55 mL, 57.1 mmol) was added a slurry of 2-oxopropanal benzylhydrazone (10.1 g, 57.1 mmol) in water (250 mL) and methanol (25 mL). The resulting mixture was heated at reflux for 3 hours before cooling to room temperature. The mixture was extracted with EtOAc (2×100 mL) and the combined organic extracts were washed with water, saturated aqueous NaCl, dried over Na2SO4, filtered and concentrated. The crude material was purified by CombiFlash (120 g column, 0-100% EtOAc/heptane gradient) to provide 1-(1-benzyl-4-hydroxy-1H-pyrazol-3-yl)ethanone (4.07 g, 33%).

1. temperatureThe resulting mixture was heated
2. temperatureat reflux for 3 hours
3. extractionThe mixture was extracted with EtOAc (2×100 mL)
4. washthe combined organic extracts were washed with water, saturated aqueous NaCl
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated
8. customThe crude material was purified by CombiFlash (120 g column, 0-100% EtOAc/heptane gradient)