F[C:2]1[CH:3]=[C:4]([C:8](=O)[CH2:9][CH2:10][CH3:11])[CH:5]=[CH:6][CH:7]=1.C([O-])(=O)C.[NH4+:17].C([BH3-])#N.[Na+].[ClH:22]>CO>[Cl:22][C:2]1[CH:3]=[C:4]([CH:8]([NH2:17])[CH2:9][CH2:10][CH3:11])[CH:5]=[CH:6][CH:7]=1To a solution of 1-(3-fluorophenyl)butan-1-one (430 mg, 2.4 mmol) and ammonium acetate (1.09 g, 14.1 mmol) in methanol (10 mL) under nitrogen was added sodium cyanoborohydride (2.35 ml, 1M solution in THF, 2.35 mmol). The solution was stirred at room temperature for 38 h. after which time conc. HCl was added to give a pH˜2. After bubbling had ceased the solvent was removed under reduced pressure and the residue dissolved in ethyl acetate and water. The organic phase was collected and the aqueous phase washed with ethyl acetate (20 mL). The aqueous phase was basified to pH˜10 with solid KOH and the product extracted into ethyl acetate (3×20 mL). The organic layers were combined, washed with brine, dried (Na2SO4) and concentrated to give a pure product (120 mg, 28%).
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