[CH:1]1([NH:7][CH2:8][CH:9]([OH:11])[CH3:10])[CH2:6][CH2:5][CH2:4][CH2:3][CH2:2]1.C=O.[BH-](OC(C)=O)(OC(C)=O)O[C:16](C)=O.[Na+].C(O)(=O)C>ClCCCl.C(OCC)(=O)C.[OH-].[Na+]>[CH:1]1([N:7]([CH3:16])[CH2:8][CH:9]([OH:11])[CH3:10])[CH2:6][CH2:5][CH2:4][CH2:3][CH2:2]1To a stirred solution of 1-(cyclohexylamino)-propan-2-ol (crude 2.6 g) in DCE (30 mL) were added successively HCHO (35% in water, 2.1 mL, 24.8 mmol), Na(OAc)3BH (10.5 g, 49.6 mmol) and acetic acid (1 mL) at ice-cold conditions. The resulting mixture was allowed to stir at rt for 16 hours. The reaction was diluted with ethyl acetate and basified with 1N NaOH. The organic layer was separated, washed with water and brine, dried over Na2SO4, filtered and concentrated. The crude material was purified by chromatography on silica-gel (230-400 mesh) eluting with 5% MeOH/DCM to provide 1-(cyclohexyl(methyl)amino)propan-2-ol. Yield: 1.0 g 1H NMR (DMSO-d6) δ 4.11 (brs, 1 H), 3.65-3.57 (m, 1 H), 2.35-2.20 (m, 3 H), 2.19 (s, 3 H), 1.72-1.68 (m, 4 H), 1.57-1.54 (m, 1 H), 1.24-1.05 (m, 5 H), 1.01 (d, J=6 Hz, 3 H).
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