Reacción #657251

Ecuación de reacción

ammonium chloride

n-butyllithium

19

5,7-Dibromo-2,3-dihydrobenzofuran

N,N-dimethylformamide

→

crystals

Rendimiento 27.1%

5-Bromo-2,3-dihydrobenzofuran-7-carbaldehyde

Rendimiento 27.1%

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrowas degassed at −78° C.
2. 2
   OtroThe solvent was removed
3. 3
   Lavadowashed with water (3×50 mL)
4. 4
   Secadothen dried with anhydrous sodium sulfate
5. 5
   OtroSolvent removal

Procedimiento

A sample of 19 (6.0 g, 26.5 mmol) in freshly distilled dry THF was degassed at −78° C. and n-butyllithium (25 mL of 1.05 M, 26 mmol) was added dropwise by syringe. Then N,N-dimethylformamide (2.9 mL, 26 mmol) was added dropwise via syringe. The reaction mixture was allowed to come to room temperature overnight. Saturated ammonium chloride (10 mL) was added to and the mixture was stirred for 30 minutes. The solvent was removed and the residue was taken up in dichloromethane (50 mL), and washed with water (3×50 mL) then dried with anhydrous sodium sulfate. Solvent removal yielded yellow crystals (1.6 g) which were washed with ether and recrystallized from a minimum of hot methanol to give white crystals of 20 (1.32 g, 22%) mp=99-100° C.

Fuente