3-Hydroxybenzaldehyde → 1-(3-Hydroxybenzyl)piperidine

Reaction equation

[OH:1][C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][CH:9]=1)[CH:5]=O.[NH:10]1[CH2:15][CH2:14][CH2:13][CH2:12][CH2:11]1.B([O-])([O-])O.[Na+].[Na+]>CO>[N:10]1([CH2:5][C:4]2[CH:3]=[C:2]([OH:1])[CH:9]=[CH:8][CH:7]=2)[CH2:15][CH2:14][CH2:13][CH2:12][CH2:11]1

Participants

Procedure

3-Hydroxybenzaldehyde (III) (0.246 mol, 30 g) was dissolved into 150 ml of methanol. Piperidine (IV) (0.6 mol, 52 g) was added to the solution and the mixture was stirred at room temperature to dissolution. To the solution was added under ice cooling sodium hydrogen borate (0.247 mol, 9.4 g) while stirring over 1 hour, followed by continued stirring for 1 hour at room temperature. The reaction mixture was concentrated under vacuum. The residue was dissolved in 200 ml of 3N hydrochloric acid and washed twice with 50 ml of ethyl acetate. The water layer was alkalinized (pH 10) with about 50 ml of concentrated aqueous ammonia to deposit crystals. The crystals were collected by filtration, washed with water, dried under vacuum, and recrystallized from a mixed solvent of acetone and n-hexane, to obtain 40 g of 3-piperidinomethylphenol (V) (yield: 84.7%). m.p. 135°-138° C.