N-Benzoylglycine (9.9 mg, 0.055 mmol), 3-ethyl-1-(3-(dimethylaminopropyl)carbodiimide hydrochloride (EDCI) (10.5 mg) and 1-hydroxybenzotriazole hydrate (HOBt) (7.4 mg) were added to a solution of 3-amino-1-(4-chlorobenzyl)pyrrolidine dihydrochloride (14.2 mg, 0.050 mmol) and Et3N (15.2 mg) in CHCl3 (2.5 mL). The reaction mixture was stirred at 25° C. for 16 h, washed with 2 N aqueous NaOH (2 mL×2) and brine (1 mL). After filtration through a PTFE membrane filter, the solvent was removed under reduced pressure to afford 3-(N-benzoylglycyl)amino-1-(4-chlorobenzyl)pyrrolidine (compound No. 1) as a pale yellow oil (17.7 mg, 95%): The purity was determined by RPLC/MS (95%); ESI/MS m/e 372.0 (M++H, C20H22ClN3O2).
