Reaktion #49682

Reaktionsgleichung

Phosphorus tribromide

5-(2-hydroxyethyl)-2,3-dihydrobenzofuran

→

title compound

5-(2-bromoethyl)-2,3-dihydrobenzofuran

Lösungsmittel

carbon tetrachloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture heated
2. 2
   Temperaturunder reflux for 3 hours
3. 3
   Sonstigethe mixture was partitioned between 10% aqueous sodium carbonate (20 ml) and dichloromethane (20 ml)
4. 4
   SonstigeThe layers were separated
5. 5
   Extraktionthe aqueous layer extracted with dichloromethane (2×10 ml)
6. 6
   TrocknenThe combined dichloromethane extracts were dried (MgSO4)
7. 7
   Einengenconcentrated in vacuo

Vorschrift

Phosphorus tribromide (0.37 g) was added to a solution of 5-(2-hydroxyethyl)-2,3-dihydrobenzofuran (0.612 g) in carbon tetrachloride (3 ml) and the mixture heated under reflux for 3 hours. On cooling to room temperature, the mixture was partitioned between 10% aqueous sodium carbonate (20 ml) and dichloromethane (20 ml). The layers were separated and the aqueous layer extracted with dichloromethane (2×10 ml). The combined dichloromethane extracts were dried (MgSO4) and concentrated in vacuo to give the title compound as an oil which crystallised on standing, yield 0.584 g, m.p. 60°-62° C. 1H N.m.r. (CDCl3)δ=7.10 (s, 1H); 7.00-6.95 (d, 1H); 6.80-6.70 (d, 1H); 4.65-4.55 (t, 2H); 3.60-3.50 (t, 2H); 3.25-3.15 (t, 2H); 3.15-3.10 (t, 2H) ppm.

Quelle