6-Methoxypyridine-3-carbaldehyde → 6-Hydroxynicotinaldehyde

Participants

Reaction Steps

6-Methoxy-pyridine-3-carbaldehyde (1.0 g, 7.29 mMol) was dissolved in hydrobromic acid (14 mL, 48% in water) and the resulting solution heated to 150 degrees gradually over one hour. The solution was then cooled to room temperature and concentrated to dryness on a rotary evaporator. Methanol (4 mL) and acetone (2 mL) were added and the solution washed with diethyl ether (3×15 mL). Water (10 mL) was added and the pH adjusted to neutral with sodium bicarbonate. The solution was then filtered and concentrated to dryness on a rotary evaporator to yield a tan solid. Purification by flash column chromatography on silica gel using 30% methanol in chloroform as eluant yielded 1.09 g (73% yield ) of 6-Oxo-1,6-dihydro-pyridine-3-carbaldehyde as a hydrobromide salt. 1H NMR (DMSO-d6): δ=12.30 (br s, 1H), 9.60 (s, 1H), 8.26 (m, 1H), 7.75 (dd, 1H, J=9.5, 2.6Hz), 6.41 (d, 1H, J=9.5 Hz). LC/MS (Method A), rt=0.25 mins., purity=98%, calculated mass=123,[M−H]−=122. HPLC (Method C): rt=1.76 mins., purity=91.2% @ 210-370nm and 91.5% (286 nm.

Provenance & Evidence