1,2-Dichloroethane → 1-[2-(4-Amino-3-chloro-benzoylamino)-propionyl]-pyrrolidine-2-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a solution of 95 (10.50 g, 27.9 mmol) in MeOH (100 ml) was added a suspension of 10% Pd/C (5.00 g) in EtOAc (50 ml). The mixture was stirred under H2 for 48 hours, filtered through celite and the solvent evaporated to yield a waxy solid. This was dissolved in CH2Cl2 (100 ml) and DMF (50 ml) and the solution cooled to 0° C. 4-Amino-3-chlorobenzoic acid (5.82 g, 27.2 mmol), DIEA (14.58 mL, 83.7 mmol), HOBT (3.77 g, 27.9 mmol) and EDC (6.68 g, 34.8 mmol) were added and the solution stirred at 0° C. for 15 mins then at room temperature for 24 hours. The reaction mixture was diluted with EtOAc, washed with NaHSO4 (2×), 10% NaHCO3 (2×) and brine then dried over MgSO4, filtered and evaporated. The crude product was purified by flash column chromatography, using CH2Cl2/MeOH (99/1 to 97/3%) to yield the title compound as a white solid (7.75 g, 70% yield). 1H-NMR (500 MHz, CD3OD) δ 1.27-1.67 (m, 12H), 1.82-2.14 (m, 4H), 3.48-3.85 (m, 2H), 4.26-4.53 (m, 3H), 4.81-4.98 (m, 1H), 6.71 (d, 1H), 7.15 (m, 1H), 7.50 (dd, 1H), 7.75 (d, 1H). Analytical HPLC 10.83 min. LC-MS (ES+) m/e=396.3 (MH+).

Provenance & Evidence