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

Participants

Reaction Conditions

Reaction Steps

To a solution of 3 (19.0 g, 45.4 mmol) in MeOH (200 mL) was added 10% activated Pd on C (2.0 g) in EtOAc (50 mL) and the reaction stirred under H2 for 18 hours. The solution was filtered through Celite and the solvent evaporated to yield a viscous, colorless oil. The free amine was dissolved in dry CH2Cl2/DMF (2:1, 120 mL), the solution cooled to 0° C. and 4-amino-3-chlorobenzoic acid (7.79 g, 45.4 mmol) and DIPEA (7.90 mL, 45.4 mmol) were added. The reaction was stirred for 10 minutes, then EDC (11.32 g, 59.1 mmol) was added. The mixture was stirred at 0° C. for 30 minutes then at room temperature for 18 hours. The solution was diluted with EtOAc (300 mL), washed with 0.5N NaHSO4 (2×250 mL), 10% NaHCO3 (2×250 mL), saturated NaCl (150 mL), dried over MgSO4, and evaporated to dryness. Flash column chromatography on silica gel using CH2Cl2/MeOH, (99/1 to 98/2%) yielded the title compound as a white solid (19.25 g, 97% yield): 1H-NMR (500 MHz, CDCl3) δ 1.12 (s, 9H), 1.48 (s, 9H), 1.85-1.99 (m, 2H), 2.01-2.13 (m, 1H), 2.18-2.29 (m, 1H), 3.63-3.73 (m, 1H), 3.84-3.93 (m, 1H), 4.30-4.41 (m, 1H), 4.86 (d, 1H), 6.73 (d, 1H), 7.51 (d, 1H), 7.73 (s, 1H). Analytical HPLC (cyano column): 12.59 min. LC-MS (ES+) m/e=438.5 (M+H).

Provenance & Evidence