Trifluoroacetic acid → HCID 58641227, compound

Participants

Reaction Steps

A solution of tert-butyl(2S)-4-(2,5-difluorophenyl)-2-phenyl-2,5-dihydro-1H-pyrrole-1-carboxylate (5-5, 1.00 g, 2.80 mmol, 1 equiv) in a 4:1 mixture of dichloromethane and trifluoroacetic acid (20 mL) was stirred for 30 minutes, then concentrated. The residue was dried via benzene azeotrope (1×50 mL), then dissolved in DMF (30 mL). N-(tert-butoxycarbonyl)-3,3-dimethylaspartic acid (29-3, 1.08 g, 4.20 mmol, 1.50 equiv), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, 0.805 g, 4.20 mmol, 1.50 equiv), 1-hydroxy-7-azabenzotriazole (0.571 g, 4.20 mmol, 1.50 equiv) and triethylamine (2.73 mL, 19.6 mmol, 7.00 equiv) were added, and the resulting mixture was stirred at 23° C. for 20 hours. The reaction mixture was partitioned between water, acidified to pH 2, and ethyl acetate (2×100 mL). The combined organic layers were dried over sodium sulfate and concentrated. The residue was purified by flash column chromatography through silica gel (hexane initially, grading to 100% EtOAc) followed by reverse-phase LC (H2O/CH3CN gradient w/0.1% TFA present) to provide (3S)-3-[(tert-butoxycarbonyl)amino]4-[(2S)-4-(2,5-difluorophenyl)-2-phenyl-2,5-dihydro-1H-pyrrol-1-yl]-2,2-dimethyl-4-oxobutanoic acid (29-4) as a white foam. 1H NMR (500 M CDCl3) major rotamer: δ 7.28 (m, 5H), 7.05 (m, 3H), 6.40 (s, 1H), 5.89 (br s, 1H), 5.74 (d, 1H, J=10.2 Hz), 5.17 (d, 1H, J=14.2 Hz), 4.93 (ddd, 1H, J=13.9, 4.4, 1.7 Hz), 4.62 (d, 1H, J=10.2 Hz), 1.45 (s, 9H), 1.30 (s, 3H), 1.05 (s, 3H). LRMS m/z (M+H) 501.5 found, 501.2 required.

Provenance & Evidence