Réaction #1121794

Équation de réaction

1-(4-bromo-pyridin-2-yl)-4,4-dimethoxy-butan-1-one

1-(4-Bromo-pyridin-2-yl)-4,4-dimethoxy-butan-1-one

trifluoroacetic acid

→

4-(4-bromo-pyridin-2-yl)-4-oxo-butyraldehyde

4-(4-Bromo-pyridin-2-yl)-4-oxo-butyraldehyde

Solvants

CH2Cl2

Conditions de réaction

Traitement

1. 1
   ConcentrationThe reaction is concentrated
2. 2
   workup.DISSOLUTIONthe residue dissolved in ethyl acetate (150 mL)
3. 3
   Lavagewashed with water 3 times
4. 4
   Séchagedried over Na2SO4
5. 5
   Autrethe solvent evaporated
6. 6
   AutreThe residue is purified by flash column chromatography (30% EtOAc in hexanes)

Mode opératoire

To a solution of 1-(4-bromo-pyridin-2-yl)-4,4-dimethoxy-butan-1-one (2) (crude from Step 2, 11 g, 38.2 mmol) in 100 of CH2Cl2 at room temperature is added trifluoroacetic acid (10.9 g, 95.4 mmol) and the reaction mixture is stirred overnight. The reaction is concentrated, the residue dissolved in ethyl acetate (150 mL) and washed with water 3 times. The organic layers are combined, dried over Na2SO4 and the solvent evaporated. The residue is purified by flash column chromatography (30% EtOAc in hexanes) to give 4-(4-bromo-pyridin-2-yl)-4-oxo-butyraldehyde (3) as an yellow oil. (4.16 g, 45%): MS ES+244.04.

Source