Hydrochloric Acid → (-)-3-phenyl-3-(2-hydroxyethyl)pyrrolidine (R,R)-di-p-anisoyltartaric acid

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Reaction Steps

Combine (R,R)-di-p-anisoyltartaric acid (110 g, 2.62 mmol) in water/methanol (13.6 mL/13.6 mL). Add 12M hydrochloric acid solution (0.217 mL, 2.63 mmol). Add a hot solution of 3-phenyl-3-(2-hydroxyethyl)pyrrolidine (1.0 g, 5.23 mmol) in methanol (13.6 mL). Heat to reflux. After 30 minutes, slowly cool to ambient temperature to give a solid. Collect the solid by filtration and recrystallize the solid twice from methanol/water, once from methanol/2-butanone, and once from ethanol to give (-)-3-phenyl-3-(2-hydroxyethyl)pyrrolidine (R,R)-di-p-anisoyltartaric acid. After conversion of a sample to the 3,4,5-trimethoxybenzamide using sodium carbonate and 3,4,5-trimethoxybenzoyl chloride in acetone/water, analysis on HPLC using a CHIRALPAK AD (10 μm×4.6 cm×250 cm) column eluting with pentane/ethanol/methanol/triethylamine (80/15/5/0.1) with a flow rate of 1.5 mL/minute indicates an enantiomeric excess of 98%, (98% ee), retention time 22.30 minutes for the 3,4,5-trimethoxybenzamide of the isomer prepared from the (-)-isomer of (R,R)-di-p-anisoyltartaric acid salt.

Provenance & Evidence