Reaktion #792166

Reaktionsgleichung

1,2-dibromotetrachloroethane

N-dimethylsulfamoylpyrazole

n-butyllithium

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title product

Ausbeute 89.4%

3-Bromo-N,N-dimethyl-1H-pyrazole-1-sulfonamide

Ausbeute 89.4%

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeA thick solid formed during the addition
2. 2
   workup.ADDITIONUpon completion of the addition the reaction mixture
3. 3
   Temperaturwas maintained for an additional 15 minutes
4. 4
   Temperaturwhile maintaining the temperature below ˜70° C
5. 5
   SonstigeThe ˜78° C. bath was removed
6. 6
   Sonstigethe reaction was quenched with water (600 mL)
7. 7
   ExtraktionThe reaction mixture was extracted with methylene chloride (4×)
8. 8
   Trocknenthe organic extracts were dried over magnesium sulfate
9. 9
   Einengenconcentrated
10. 10
    SonstigeThe crude product was further purified by chromatography on silica gel

Vorschrift

To a solution of N-dimethylsulfamoylpyrazole (44.0 g, 0.251 mol) in dry tetrahydrofuran (500 mL) at ˜78° C. was added dropwise a solution of n-butyllithium (2.5 M in hexane, 105.5 mL, 0.264 mol) while maintaining the temperature below ˜60° C. A thick solid formed during the addition. Upon completion of the addition the reaction mixture was maintained for an additional 15 minutes, after which time a solution of 1,2-dibromotetrachloroethane (90 g, 0.276 mol) in tetrahydrofuran (150 mL) was added dropwise while maintaining the temperature below ˜70° C. The reaction mixture turned a clear orange; stirring was continued for an additional 15 minutes. The ˜78° C. bath was removed and the reaction was quenched with water (600 mL). The reaction mixture was extracted with methylene chloride (4×), and the organic extracts were dried over magnesium sulfate and concentrated. The crude product was further purified by chromatography on silica gel using methylene chloride/hexane (50:50) as eluent to afford the title product as a clear colorless oil (57.04 g).

Quelle