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

Participants

Reaction Steps

Add a hot solution of 3-phenyl-3-(2-hydroxyethyl)pyrrolidine (5.0 g, 20.2 mmol) in ethanol (100 mL) to a refluxing solution of (R,R)-di-p-anisoyltartaric acid (8.46 g, 20.2 mmol, containing a small amount of acetone) in ethanol (200 mL). After the addition is complete, slowly cool to ambient temperature to give a solid. Collect the solid by filtration and recrystallize the solid three times from ethanol to give (−)-3-phenyl-3-(2-hydroxyethyl)pyrrolidine(R,R)-di-p-anisoyltartaric acid salt: mp; 178.0-179.0° C. Elemental Analysis calculated for C12H17NO.C20H18O10: C 63.05; H 5.79; N 2.30; Found: C 62.72; H 5.80; N 2.33. 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 99.9%, (99.9% ee), retention time 22.30 minutes for the 3,4,5-trimethoxybenzamide prepared from the (−)-isomer of (R,R)-di-p-anisoyltartaric acid salt.

Provenance & Evidence