Reaktion #9277

Reaktionsgleichung

water

n-butyllithiumhexane

2-ethylpyrazolo[1,5-a]pyridine

1,2-dibromo-1,1,2,2-tetrachloroethane

→

title compound

Ausbeute 73.1%

7-Bromo-2-ethylpyrazolo[1,5-a]pyridine

Ausbeute 73.1%

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGstirring
2. 2
   workup.WAITwas continued for 30 minutes
3. 3
   Extraktionextraction
4. 4
   Waschenthe organic layer was washed with water and brine
5. 5
   TrocknenAfter drying over anhydrous magnesium sulfate and filtration
6. 6
   Einengenthe solvent was concentrated under reduced pressure
7. 7
   Sonstigethe residue was purified by silica gel column chromatography

Vorschrift

After dissolving 2-ethylpyrazolo[1,5-a]pyridine (80 mg) in tetrahydrofuran (1 mL), an n-butyllithiumhexane solution (1.6 M; 0.58 mL) was added dropwise at −78° C. under a nitrogen stream, and the mixture was stirred for 30 minutes. A solution of 1,2-dibromo-1,1,2,2-tetrachloroethane (196 mg) in tetrahydrofuran (0.5 mL) was added to the reaction mixture, and stirring was continued for 30 minutes. The temperature was increased to room temperature, water was added, extraction was performed with ethyl acetate and the organic layer was washed with water and brine. After drying over anhydrous magnesium sulfate and filtration, the solvent was concentrated under reduced pressure, the residue was purified by silica gel column chromatography and the title compound (90 mg) was obtained from the n-hexane:ethyl acetate (20:1) fraction as a light brown oil.

Quelle