(S)-2-((S)-1-tert-butoxycarbonyl-ethylamino)-3-(2',5'-dichloro-biphenyl-4-yl)-propionic acid benzyl ester → (S)-2-((S)-1-tert-butoxycarbonyl-ethylamino)-3-(2',5'-dichloro-biphenyl-4-yl)-propionic acid

Participants

Reaction Steps

Step 4′: A suspension of (S)-2-((S)-1-tert-Butoxycarbonyl-ethylamino)-3-(2′,5′-dichloro-biphenyl-4-yl)-propionic acid benzyl ester (580 mg, 1.10 mmol) and 5% Pd on carbon (0.146 g) in EtOAc (10 mL) was treated with H2 (balloon) and stirred at rt for 1.5 hour. The resulted precipitate was dissolved in methanol and filtered through celite pad. The filtrate was concentrated under reduced pressure and the obtained residue was re-crystallized from EtOAc to give (S)-2-((S)-1-tert-butoxycarbonyl-ethylamino)-3-(2′,5′-dichloro-biphenyl-4-yl)-propionic acid (438 mg). 1H NMR (400 MHz, DMSO-d6) δ 1.12 (d, 3H, J=7.1 Hz), 1.35 (s, 9H), 2.84 (dd, 2H, J=7.3, 13.6 Hz), 2.95 (dd, 2H, J=6.1, 13.6 Hz), 3.20 (dd, 1H, J=6.8, 13.6 Hz), 3.48 (dd, 1H, J=6.1, 7.3 Hz), 7.33 (d, 2H, J=8.6 Hz), 7.37 (d, 2H, J=8.3 Hz), 7.42-7.49 (m, 2H), 7.60 (d, 2H, J=8.6 Hz); MS: m/z (MH+) 438.

Provenance & Evidence