反应详情

温度

60 °C

1.66 g (9.27 mmol) of 6-nitro-1,2-dihydro-3H-indazol-3-one were initially charged in 20 ml of DMF, and 1.75 ml (18.5 mmol, 2.0 eq.) of dimethyl sulphate were added. The reaction mixture was heated at 60° C. for 8 h and then diluted with dichloromethane and shaken with saturated aqueous sodium carbonate solution. The aqueous phase was washed three times each with dichloromethane and with ethyl acetate and the organic fractions were discarded. Using 4N aqueous hydrochloric acid, the aqueous phase was then carefully adjusted to pH 4.5 and extracted three times with ethyl acetate. These combined organic phases were dried over magnesium sulphate and concentrated under reduced pressure. The crude product was purified by flash chromatography (silica gel 50, mobile phase: gradient cyclohexane/ethyl acetate 1:1 to ethyl acetate/methanol 15:1), giving the title compound. Yield: 770 mg (43% of theory)

1. washThe aqueous phase was washed three times each with dichloromethane
2. extractionextracted three times with ethyl acetate
3. dry with materialThese combined organic phases were dried over magnesium sulphate
4. concentrationconcentrated under reduced pressure
5. customThe crude product was purified by flash chromatography (silica gel 50, mobile phase: gradient cyclohexane/ethyl acetate 1:1 to ethyl acetate/methanol 15:1)