1,2-Diphenylpropan-2-amine → HCID 131716146, compound

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Reaction Steps

Racemic 1,2-diphenyl-2-propylamine (86 g, 0.4 mol) was dissolved in 0.5 L 95% ethanol, heated to near reflux and added to a solution of (-)-dibenzoyltartaric acid monohydrate (151.9 g, 0.4 mol) in 0.5 L 95% ethanol also at reflux. A white solid crystallized immediately. The mixture was refluxed for 5 minutes, then allowed to cool to ambient temperature. The solid was collected by filtration and dried to give 86.2 g, [α]D =94.2° (C=0.5, CH3OH). The filtrate was saved. The solid was suspended in 0.9 L of 95% ethanol, stirred and heated to reflux for 1 hour, allowed to cool to ambient temperature and the white solid collected by filtration and vacuum dried at 80° C. for 8 hours to give 60.2 g of (-)-1,2-diphenyl-2-propylamine (-)-dibenzoyl tartrate, mp 194°-195° C. [α]D =-96.0° (C=0.5, CH3OH). 5.0 g of this salt was dissolved in 250 ml CHCl3 and 200 ml 5% NH4OH shaken vigorously, the layers separated and the organic phase washed with 3×200 ml 5% NH4OH, 2×200 ml H2O and dried over MgSO4. The solvent was evaporated to give 1.75 g of (-)-1,2-diphenyl-2-propylamine as an oil. The maleate salt was prepared by dissolving this oil in 25 ml of ethyl acetate and adding the solution to a hot solution of maleic acid (1.02 g, 8.87 mmol) in 50 ml of 3/1 ethyl acetate/isopropanol. Upon cooling a white solid crystallized, which was collected by filtration and vacuum dried to give 2.05 g of (-)-1,2-diphenyl-2-propylamine maleate, mp 176°-177° C., [α]D =-27.4° (C=1, CH3OH).

Provenance & Evidence