N,N-Dimethylaniline → 7-Chloro-2,5-dimethylpyrazolo(1,5-a)pyrimidine

참여 물질

반응 단계

To a suspension of 2,5-dimethyl-4H-pyrazolo[1,5-a]pyrimidin-7-one (10.0 g, 61.3 mmol) in toluene (150 mL), add N,N-dimethylaniline (9.7 mL, 76.7 mmol). Add phosphorus oxychloride (11.2 mL, 122.6 mmol) dropwise to this white suspension. Reflux for 3 h under an inert atmosphere, cool to room temperature, and concentrate the reaction to a brown oil using reduced pressure. Dissolve the oil in ethyl acetate (250 mL) and basify with 1 N NaOH. Separate and extract the basic aqueous phase with additional ethyl acetate (2×100 mL). Combine the organic phases, dry over anhydrous magnesium sulfate, filter, and concentrate under reduced pressure to yield a brown solid. Purify the material using flash chromatography, eluting with 80% hexane/20% (30% THF/hexane) to 0% hexane/100% (30% THF/hexane) in a step gradient of 20% increments to provide a light green solid (6.65 g, 59%). ES/MS m/z (35Cl) 182.3 (M+1)+.

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