Citric Acid → Methyl 6-formylpyridine-2-carboxylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A suspension of dimethylpyridine-2,6-dicarboxylate (1.0 g, 5.12 mmol) in methanol (8 mL) and THF (3 mL) was heated at 75° C. until the solid was dissolved. NaBH4 (184 mg, 4.87 mmol) was then added portion-wise. The mixture was stirred at 70° C. for 1 h. The mixture was cooled to room temperature and 10% citric acid (1.6 mL) was added. The solution was filtered and the filtrate was evaporated to dryness, taken up in dichloromethane, dried over MgSO4 and the solvent was removed in vacuo. The residue was purified by silica gel chromatography, eluting with 0-100% EtOAc in isohexane, to provide a colourless oil which was then dissolved in toluene (20 mL) and chloroform (20 mL). MnO2 (194 mg, 22.2 mmol) was added and the mixture was stirred at room temperature for 18 h. The mixture was filtered through a pad of fluorosil, eluting with chloroform (30 mL) and the solvent was removed in vacuo to provide the title compound (249 mg, 29%) as white solid.

Herkunft & Nachweise