Reacción #2507835

Ecuación de reacción

Ethyleneglycol

p-toluenesulfonic acid

5-bromopyridine-2-carbaldehyde

→

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

Rendimiento 84.0%

Disolventes

toluene

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturaat refluxing temperature
2. 2
   Otrothe mixture is quenched with saturated aqueous NH4Cl
3. 3
   Extracciónextracted with CH2Cl2
4. 4
   Lavadowashed with H2O
5. 5
   ExtracciónThe aqueous layer is extracted with CH2Cl2
6. 6
   Extracciónthe combined organic extract
7. 7
   Lavadois washed with brine
8. 8
   Secadodried over Na2SO4
9. 9
   Concentraciónconcentrated under reduced pressure
10. 10
    OtroThe residue is purified by silica gel column chromatography (hexane-AcOEt (9:1 V/V))

Procedimiento

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).

Fuente