Pyridine → 2-[(1-Tert-butoxycarbonylamino-cyclopentanecarbonyl)-amino]-3-(4-trifluoromethanesulfonyloxy-phenyl)-propionic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

1.2 mL of Trifluoromethanesulfonic anhydride (7.1 mmol) is added slowly dropwise to a solution of 2-[(1-tert-butoxycarbonylamino-cyclopentanecarbonyl)-amino]-3-(4-hydroxy-phenyl)-propionic acid ethyl ester (2.70 g, 6.4 mmol) and 0.7 mL (8.7 mmol) of pyridine in 20 mL of CH2Cl2 at 0° C., and the solution is stirred at 0° C. for 1 hour. The reaction mixture is then partitioned between water and CH2Cl2. The organic phase is separated and washed with saturated aqueous NaHCO3 solution, dried over MgSO4, filtered, and concentrated to yield 2-[(1-tert-butoxycarbonylamino-cyclopentanecarbonyl)-amino]-3-(4-trifluoromethanesulfonyloxy-phenyl)-propionic acid ethyl ester as a tan solid; 1H NMR (250 MHz, CDCl3) δ7.25 (d, 2 H), 7.17 (d, 2 H), 4.80 (q, 1 H), 4.75 (s, 1 H), 4.10 (two quarters, 2 H), 3.12 (ABX m, 2 H), 2.00-2.20 (m, 2 H), 1.60-2.00 (m, 6 H), 1.40 (s, 9 H), 1.18 (t, 3 H).

Provenance & Evidence