1,3-Propanediamine, N'-(ethylcarbonimidoyl)-N,N-dimethyl-, monohydrochloride → tert-butyl L-prolinate

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Reaction Steps

A solution of 5-(biphenyl-4-yloxymethyl)-furan-2-carboxylic acid (of Intermediate 8; 0.134 g, 0.46 mmol), D-proline tert-butyl ester hydrochloride (Bachem; 0.22 g, 1.1 mmol), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (Avocado; 0.18 g, 0.95 mmol), and N,N-dimethylaminopyridine (0.166 g, 1.36 mmol) in tetrahydrofuran (10 mL) was stirred at room temperature for 16 h. The solvents were evaporated under reduced pressure, and water and ethyl acetate were added. The aqueous phase was extracted three times with ethyl acetate, and the combined organic layers were dried (sodium sulfate), filtered, evaporated, and purified using a Biotage Flash 40 purification system, eluting with methylene chloride/acetone 9:1, to give 5-(biphenyl-4-yloxymethyl)-furan-2-carbonyl]-D-pyrrolidine-2-carboxylic acid tert-butyl ester as a white solid (0.115 g, 56%).

Provenance & Evidence