반응 #2507835

반응 방정식

Ethyleneglycol

p-toluenesulfonic acid

5-bromopyridine-2-carbaldehyde

→

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

수율 84.0%

용매

toluene

반응 조건

후처리

1. 1
   온도at refluxing temperature
2. 2
   기타the mixture is quenched with saturated aqueous NH4Cl
3. 3
   추출extracted with CH2Cl2
4. 4
   세척washed with H2O
5. 5
   추출The aqueous layer is extracted with CH2Cl2
6. 6
   추출the combined organic extract
7. 7
   세척is washed with brine
8. 8
   건조dried over Na2SO4
9. 9
   농축concentrated under reduced pressure
10. 10
    기타The residue is purified by silica gel column chromatography (hexane-AcOEt (9:1 V/V))

실험 절차

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).

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