反应详情

温度

60 °C

Phosphorus oxychloride (18.2 mL, 195 mmol) was added portionwise to DMF (30 mL, 387 mmol) at <5° C. Pinacolone semicarbazone (15.4 g, 97.6 mmol) was added over 1 h maintaining the temperature at <5° C. The reaction mixture became very thick so an additional quantity of DMF (10 mL) was added. The mixture was heated to 60° C. for 3.5 h then allowed to cool and poured into ice. The reaction was neutralised using sodium hydroxide (40 g, 1 mol) in water (130 mL) then heated at 60° C. for 5 min. The mixture was cooled in an ice bath and acidified to pH 6 and the product extracted into EtOAc. The EtOAc was dried over MgSO4 and concentrated onto silica. The crude product was purified by flash chromatography using eluants EtOAc/heptane. Trituration in diethyl ether gave a white solid (1.02 g, 6.1 mmol, 6%).

1. temperaturemaintaining the temperature at <5° C
2. additionwas added
3. temperatureto cool
4. additionpoured into ice
5. temperaturethen heated at 60° C. for 5 min
6. temperatureThe mixture was cooled in an ice bath
7. extractionthe product extracted into EtOAc
8. dry with materialThe EtOAc was dried over MgSO4
9. concentrationconcentrated onto silica
10. customThe crude product was purified by flash chromatography