Methanol → 1-Methyl-1,2,3,6-tetrahydropyridine-4-carboaldehyde
Reaction equation
[N:1]1[CH:6]=[CH:5][C:4]([CH:7]=[O:8])=[CH:3][CH:2]=1.[BH4-].[Na+].[CH3:11]O>>[CH3:11][N:1]1[CH2:6][CH:5]=[C:4]([CH:7]=[O:8])[CH2:3][CH2:2]1Participants
4
Procedure
A solution of 4-pyridine carboxaldehyde, O-methyloxime methiodide (32.78 g, 118 mmol) in 150 ml 50% aqueous methanol was added dropwise to a solution of sodium borohydride (7.79 g, 206 mmol) in 150 ml of aqueous 50% methanol keeping the temperature 0° C. ±5° C. After the solution was stirred one hour, some of the inorganic salts were removed by filtration and the filtrate was concentrated to a mass of oily crystals in vacuo. A portion (4.5 g) of this material was partially dissolved in boiling ethyl ether, filtered, and the filtrate treated with hydrogen chloride to give 1,2,3,6-tetrahydro-1-methyl-4-pyridine carboxaldehyde, O-methyloxime, hydrochloride (2.35 g), mp 212°-214° C.