Réaction #657251

Équation de réaction

ammonium chloride

n-butyllithium

19

5,7-Dibromo-2,3-dihydrobenzofuran

N,N-dimethylformamide

→

crystals

Rendement 27.1%

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

Rendement 27.1%

Solvants

THF

Conditions de réaction

Traitement

1. 1
   Autrewas degassed at −78° C.
2. 2
   AutreThe solvent was removed
3. 3
   Lavagewashed with water (3×50 mL)
4. 4
   Séchagethen dried with anhydrous sodium sulfate
5. 5
   AutreSolvent removal

Mode opératoire

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.

Source