Citric Acid → Methyl 6-formylpyridine-2-carboxylate

Temperature

75 °C

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.

1. dissolutionwas dissolved
2. temperatureThe mixture was cooled to room temperature
3. filtrationThe solution was filtered
4. customthe filtrate was evaporated to dryness
5. dry with materialdried over MgSO4
6. customthe solvent was removed in vacuo
7. customThe residue was purified by silica gel chromatography
8. washeluting with 0-100% EtOAc in isohexane
9. customto provide a colourless oil which
10. stirringthe mixture was stirred at room temperature for 18 h
11. filtrationThe mixture was filtered through a pad of fluorosil
12. washeluting with chloroform (30 mL)
13. customthe solvent was removed in vacuo

ORD record

ord-e3509c0fb924418e93c3a95f6e4f05bc

Source dataset

uspto-grants-2015_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09133185B2