Cl.[NH:2]1[CH2:7][CH2:6][CH2:5][C@@H:4]([OH:8])[CH2:3]1.[N:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[CH:15]=O.C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+].[OH-].[Na+]>ClCCCl.O.C(O)(=O)C.C(N(CC)CC)C>[N:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[CH2:15][N:2]1[CH2:7][CH2:6][CH2:5][C@@H:4]([OH:8])[CH2:3]1
(3R)-3-Piperidinol hydrochloride (10.0 g) and triethylamine (10.13 ml) in dry 1,2-dichloroethane (350 ml) were stirred for 15 minutes at 50° C. 2-Pyridine carboxaldehyde (7.63 ml) and glacial acetic acid (4.16 ml) were added and the reaction mixture stirred for 1.5 hours at reflux. Sodium triacetoxyborohydride (34.65 g) was then added portionwise and the resulting mixture was cooled to room temperature and stirred for a further 1 hour. Water (350 ml) and 1M aqueous sodium hydroxide solution were then added until the mixture was pH12. The organic layer was separated and the aqueous extracted with chloroform, the combined organic layers were dried over magnesium sulphate and the solvent was removed under reduced pressure. The crude product was purified by column chromatography on silica gel eluting with a solvent system of 95:5, by volume, chloroform:methanol to afford (3R)-1-(2-pyridinylmethyl)-3-piperidinol (8.10 g) as a brown oil.
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