Reaktion #1741152

Reaktionsgleichung

ethyl acetate

dimethyl 5-dibromomethylpyridine-2,3-dicarboxylate

→

title compound

Ausbeute 85.0%

Dimethyl 5-formylpyridine-2,3-dicarboxylate

Ausbeute 85.0%

Lösungsmittel

dioxane

water

—

hexanes

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe resulting slurry is heated
2. 2
   Temperaturat reflux for 3 hours
3. 3
   Filtrationfiltered through a pad of diatomaceous earth
4. 4
   Waschenthe diatomaceous earth is rinsed with tetrahydrofuran
5. 5
   EinengenThe filtrate is concentrated in vacuo
6. 6
   Sonstigeto remove the dioxane and tetrahydrofuran
7. 7
   workup.ADDITIONThe resultant aqueous solution is made basic by the addition to saturated aqueous sodium bicarbonate (100 mL)
8. 8
   Extraktionextracted with methylene dichloride
9. 9
   TrocknenThe combined extracts are dried over anhydrous magnesium sulfate
10. 10
    Einengenconcentrated in vacuo
11. 11
    Sonstigeto give a residue

Vorschrift

To a solution of dimethyl 5-dibromomethylpyridine-2,3-dicarboxylate (8.32 g, 0.0227 mol) in dioxane (60 mL) and water (20 mL) is added silver nitrate (7.85 g, 0.0476 mol). The resulting slurry is heated at reflux for 3 hours. The reaction mixture is cooled to room temperature, filtered through a pad of diatomaceous earth and the diatomaceous earth is rinsed with tetrahydrofuran. The filtrate is concentrated in vacuo to remove the dioxane and tetrahydrofuran. The resultant aqueous solution is made basic by the addition to saturated aqueous sodium bicarbonate (100 mL) and extracted with methylene dichloride. The combined extracts are dried over anhydrous magnesium sulfate and concentrated in vacuo to give a residue. Chromatography of said residue using silica gel and 33% ethyl acetate in hexanes as eluant yields the title compound as a white solid, (4.31 g, 85%) mp 75° C.-77° C., identified by IR and NMR spectral analyses.

Quelle