[CH2:1]([N:8]1[CH2:13][CH2:12][CH:11]([CH3:14])[CH:10]([NH:15][CH3:16])[CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[ClH:17]>C1(C)C=CC=CC=1.C(O)C.O>[ClH:17].[ClH:17].[CH2:1]([N:8]1[CH2:13][CH2:12][CH:11]([CH3:14])[CH:10]([NH:15][CH3:16])[CH2:9]1)[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1To a solution of 23.4 kg of (1-benzyl-4-methylpiperidin-3-yl)-methylamine in 10 liters of toluene and 120 liters of ethanol at 3° C. was added 25 liters of 32% HCl in water, keeping the reaction temperature below 10° C. 100 liters of solvent was distilled off under partial vacuum, and 215 liters of ethyl acetate was added at 30° C. 210 liters of solvent was distilled off under partial vacuum, and a second 215 liters of ethyl acetate was added and another 210 liters of solvent was distilled off under partial vacuum. 111 liters of acetone was added at 35 C°, the suspension was cooled to 0° C., and then the product, (1-benzyl-4-methylpiperidin-3-yl)-methylamine bishydrochloride, was filtered off and washed with 55 liters of acetone. The wet-cake was reslurried 3 times in ethanol (10 volume equivalents at reflux) to upgrade the diasteromeric ratio of cis:trans from 91:9 to greater than 97:3. Total recovery was 19.4 kg, 62% yield. 1H NMR (CD3OD, 400 MHz): 7.55 (m, 5H), 4.88 (s, 3H), 4.52 (d, J=12.8 Hz, 1H), 4.45 (d, J=12.8 Hz, 1H), 3.76 (m, 1H), 3.67 (m, 1H), 3.40-3.00 (m, 3H), 2.78 (3, 3H), 2.55 (m, 1H), 2.14 (m, 1H), 1.90 (m, 1H), 1.16 (d, J=7.2 Hz, 3H)
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