2-(3-(3,4-Dichlorophenyl)pyrrolidin-3-yl)ethanol → (S)-3-(3,4-dichlorophenyl)-3-(2-hydroxyethyl)pyrrolidine (R,R)-di-p-anisoyltartaric acid

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Reaction Steps

Combine 3-(3,4-dichlorophenyl)-3-(2-hydroxyethyl)pyrrolidine (1.0 g, 38.5 mmol) and butanone. Add a solution of (R,R)-di-p-anisoyltartaric acid (1.6 g, 38.0 mmol) in butanone (80 mL). Heat to reflux. After 15 minutes, cool to ambient temperature and then cool further in an salt-ice bath. Filter the solid that forms and rinse with butanone. Recrystallize the solid from water/methanol to give (S)-(−)-3-(3,4-dichlorophenyl)-3-(2-hydroxyethyl)pyrrolidine (R,R)-di-p-anisoyltartaric acid salt: mp; 201-204° C. (dec). [α]2D0=−18.9° (c=0.60, dimethylsulfoxide). X-ray diffraction analysis of a single crystal confirms the (S)-configuration. Analysis on HPLC, on an analytical sample of the free amine obtained by extraction, using a CHIRALPAK AD 25 cm×0.46 cm column eluting with pentane/methanol/triethylamine (80/10/0.1) with a flow rate of 1.0 mL/minute indicates an enantiomeric excess of 96%, (96% ee), retention time of the (S)-isomer 11.2 minutes, retention time of the (R)-isomer 14.5 minutes.

Provenance & Evidence