تفاعل #2507835

معادلة التفاعل

Ethyleneglycol

p-toluenesulfonic acid

5-bromopyridine-2-carbaldehyde

→

5-bromo-2-(1,3-dioxolan-2-yl)pyridine

المردود 84.0%

المذيبات

toluene

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةat refluxing temperature
2. 2
   أخرىthe mixture is quenched with saturated aqueous NH4Cl
3. 3
   استخلاصextracted with CH2Cl2
4. 4
   غسيلwashed with H2O
5. 5
   استخلاصThe aqueous layer is extracted with CH2Cl2
6. 6
   استخلاصthe combined organic extract
7. 7
   غسيلis washed with brine
8. 8
   تجفيفdried over Na2SO4
9. 9
   تركيزconcentrated under reduced pressure
10. 10
    أخرىThe residue is purified by silica gel column chromatography (hexane-AcOEt (9:1 V/V))

الإجراء التجريبي

Ethyleneglycol (14.88 g, 0.24 mol) and p-toluenesulfonic acid (3 g, 0.16 mol) are added to a solution of 5-bromopyridine-2-carbaldehyde (30 g, 0.16 mol) in toluene (150 ml) at room temperature and the mixture is stirred for 10 hrs at refluxing temperature. After cooling to room temperature, the mixture is quenched with saturated aqueous NH4Cl, extracted with CH2Cl2 and washed with H2O. The aqueous layer is extracted with CH2Cl2 and the combined organic extract is washed with brine, dried over Na2SO4, and concentrated under reduced pressure. The residue is purified by silica gel column chromatography (hexane-AcOEt (9:1 V/V)) to afford 5-bromo-2-(1,3-dioxolan-2-yl)pyridine (30.9 g, 84%) as a colorless oil. %). 1H NMR (400 MHz, CDCl3) δ 8.69 (s, 1H), 7.87 (m, 1H), 7.45 (m, 1H), 5.83 (s, 1H), 4.13 (m, 4H).

المصدر