Trifluoroacetic acid → 4-{2-[2-(Benzyloxycarbonyl-methyl-amino)-propionylamino]-3-hydroxy-butyryl}-3-(6-fluoro-1H-indol-3-yl)-hexahydro-pyrrolo[3,2-b]pyrrole-1-carboxylic acid benzyl ester

Participants

Reaction Steps

A solution containing crude 45 (330 mg, 0.44 mmol) in DCM (10 mL) was treated with TFA (3 mL) at ambient temperature. After 2 h, the reaction mixture was concentrated in vacuo. The residue was dissolved in EtOAc and the resultant organic solution was washed successively with saturated aqueous NaHCO3 and brine, dried over anhydrous Na2SO4, filtered, and concentrated to afford 300 mg of 46 as a pale brown-colored foam which was used without further purification. 1H NMR (CDCl3, 300 MHz) mixture of rotamers: δ8.38 (s, 0.5H), 8.34 (s, 0.5H), 8.12 (dd, J=5.1, 8.7 Hz, 0.5H), 8.03 (dd, J=5.4, 8.4 Hz, 0.5H), 7.35-7.26 (m, 5H), 7.05-6.87 (m, 2H), 6.77 (s, 0.5H), 6.62 (s, 0.5H), 5.29-5.12 (m, 3H), 4.76-4.52 (m, 1.5H), 4.34-4.30 (m, 1H), 4.22-4.19 (m, 0.5H), 3.89 (app t, J=5.4 Hz, 1H), 3.57-3.42 (m, 2H), 2.82 (s, 3H), 2.45-2.39 (m, 0.5H), 2.27-2.21 (m, 0.5H), 1.90 (br s, 1H), 1.38 (d, J=7.5 Hz, 3H), 1.16 (d, J=6.3 Hz, 3H) ppm. Mass spectrum, m/z [700.3] (M+H)+.

Provenance & Evidence