反応 #6524

反応方程式

sodium acetate

5-(pyrrol-2-yl)oxazole

dimethylformamide

phosphorus oxychloride

→

5-(5-formylpyrrol-2-yl)oxazole

収率 80.0%

溶媒

chloroform

1,2-dichloroethane

反応条件

後処理

1. 1
   workup.STIRRINGThe mixture was stirred 20 minutes
2. 2
   温度while cooling in an ice bath
3. 3
   温度The reaction mixture was then heated
4. 4
   温度under reflux for 20 minutes
5. 5
   温度After heating
6. 6
   温度under reflux for 20 minutes
7. 7
   温度the mixture was cooled to room temperature
8. 8
   その他the organic layer separated
9. 9
   洗浄washed with aqueous sodium carbonate
10. 10
    乾燥dried over anhydrous sodium sulfate
11. 11
    その他evaporation of the solvent at reduced pressure
12. 12
    その他the crude product was purified by column chromatography with chloroform elution

実験手順

To an ice cooled 1 mL dimethylformamide was added 0.82 g (5.4 mmol) of phosphorus oxychloride while stirring under a nitrogen atmosphere. The mixture was stirred 20 minutes and then was added a solution of 0.60 g (4.5 mmol) of 5-(pyrrol-2-yl)oxazole in 15 mL of 1,2-dichloroethane while cooling in an ice bath. The reaction mixture was then heated under reflux for 20 minutes. After cooling to room temperature, 50 mL of chloroform was added followed by 60 mL of saturated aqueous sodium acetate. After heating under reflux for 20 minutes, the mixture was cooled to room temperature and the organic layer separated, washed with aqueous sodium carbonate and dried over anhydrous sodium sulfate. Following evaporation of the solvent at reduced pressure, the crude product was purified by column chromatography with chloroform elution to give 0.58 g (80%) of 5-(5-formylpyrrol-2-yl)oxazole as a white solid, m.p. 152°-153° C.; 1H-NMR (Acetone-d6) δ 6.68 (d, 1H, ArH), 7.09 (d, 1H, ArH), 7.61 (S, 1H, ArH), 8,22 (s, 1H, ArH), 9.57 (s, 1H, CHO).

出典