تفاعل #6524

معادلة التفاعل

sodium acetate

5-(pyrrol-2-yl)oxazole

dimethylformamide

phosphorus oxychloride

→

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

المردود 80.0%

المذيبات

chloroform

1,2-dichloroethane

ظروف التفاعل

المعالجة

1. 1
   workup.STIRRINGThe mixture was stirred 20 minutes
2. 2
   درجة الحرارةwhile cooling in an ice bath
3. 3
   درجة الحرارةThe reaction mixture was then heated
4. 4
   درجة الحرارةunder reflux for 20 minutes
5. 5
   درجة الحرارةAfter heating
6. 6
   درجة الحرارةunder reflux for 20 minutes
7. 7
   درجة الحرارةthe mixture was cooled to room temperature
8. 8
   أخرىthe organic layer separated
9. 9
   غسيلwashed with aqueous sodium carbonate
10. 10
    تجفيفdried over anhydrous sodium sulfate
11. 11
    أخرىevaporation of the solvent at reduced pressure
12. 12
    أخرىthe crude product was purified by column chromatography with chloroform elution

الإجراء التجريبي

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).

المصدر