反応 #1552102

反応方程式

Phosphorus pentoxide

(2,6-dibromo-9H-xanthen-9-yl)methanol

→

2,7-dibromodibenzo[b,f]oxepine

収率 79.4%

溶媒

toluene

反応条件

後処理

1. 1
   温度the suspension was heated
2. 2
   温度under reflux for 20 min
3. 3
   その他toluene was removed by decantation
4. 4
   洗浄The residual solid was washed with toluene (2×100 mL) by further decantation
5. 5
   温度The combined organics were cooled in an ice bath
6. 6
   workup.ADDITIONbrine (400 mL) was added slowly
7. 7
   その他The layers were separated
8. 8
   洗浄the organic washed with water (300 mL), brine (300 mL)
9. 9
   乾燥dried over anhydrous MgSO4
10. 10
    その他evaporated to dryness
11. 11
    その他to give a yellow oily solid
12. 12
    その他The product was purified by column chromatography (SiO2

実験手順

Phosphorus pentoxide (5.04 g, 35.5 mmol) was added portion-wisely to a stirred solution of (2,6-dibromo-9H-xanthen-9-yl)methanol (10-1) (1.01 g, 2.73 mmol) in toluene (100 mL) and the suspension was heated under reflux for 20 min. The mixture was allowed to cool to rt and toluene was removed by decantation. The residual solid was washed with toluene (2×100 mL) by further decantation. The combined organics were cooled in an ice bath and brine (400 mL) was added slowly. The layers were separated and the organic washed with water (300 mL), brine (300 mL), dried over anhydrous MgSO4 and evaporated to dryness, to give a yellow oily solid. The product was purified by column chromatography (SiO2, O-10% EtOAc/isohexanes) to give 2,7-dibromodibenzo[b,f]oxepine (10-2) (763 mg, 79% yield) as a clear oil. 1H NMR (CDCl3): δ 7.41-7.36 (1H, m), 7.33-7.31 (1H, m), 7.29-7.24 (2H, m), 7.04-6.99 (2H, m), 6.68-6.57 (2H, m) ppm.

出典