Reaction Steps
Cbz-Phe(4-CH2NHBoc)-OH (214 mg, 0.5 mmol, 1 equiv.) was dissolved in DCM. HBTU (228 mg, 0.6 mmol, 1.2 equiv.), HCl.H-Leu-OMe (100 mg, 0.55 mmol, 1.1 equiv.) and DiPEA (0.29 ml, 1.75 mmol, 3.5 equiv.) were added and the mixture was stirred for 2 hours before being concentrated. The residue was dissolved in ethyl acetate (EA) and washed with 1M HCl (2×), sat. aq. NaHCO3 (4×), brine and dried over MgSO4. Column chromatography (tol->30% EA:tol) yielded the title compound (282 mg, 508 μmol, quant.). 1H NMR (400 MHz, CDCl3): δ ppm 7.35-7.22 (m, 5H), 7.19-7.04 (m, 4H), 6.81 (d, J=6.7 Hz, 1H), 5.76 (d, J=8.4 Hz, 1H), 5.16-4.94 (m, 2H), 4.69-4.45 (m, 2H), 4.26-4.11 (m, 2H), 3.67 (s, 3H), 3.13-2.88 (m, 2H), 1.64-1.47 (m, 3H), 1.44 (s, 9H), 0.94-0.81 (m, 6H). 13C NMR (101 MHz, CDCl3): δ ppm 172.83, 170.76, 155.81, 137.23, 136.04, 135.30, 129.37, 128.28, 127.92, 127.70, 127.57, 79.13, 66.70, 55.73, 52.06, 50.51, 44.19, 41.08, 37.94, 28.23, 24.51, 22.52, 21.69.
