Reaction Steps
Intermediate 60 was prepared as described above for the preparation of intermediate 52. From 266 mg of N-(Boc)-L-Tyrosine methyl ester and 208 mg of Intermediate 8F was prepared 360 mg of BOC-protected intermediate methyl ester (79% yield; 1H NMR (CDCl3, 300 MHz) δ8.06-8.03 (m, 2H), 7.46-7.44 (m, 3H), 7.04 (d, 2H, J=8.4), 6.85 (d, 2H, J=8.4), 4.97 (d, 1H, J=7.6), 4.57 (m, 1H), 3.99 (t, 2H, J=6.0), 3.74 (s, 3H), 3.05 (m, 2H), 2.77-2.65 (m, 4H), 2.19 (t, 2H, J=6.6), 1.45 (s, 9H), 1.24 (t, 3H, J=7.5); From 352 mg of BOC-protected ester intermediate was prepared the crude TFA salt of intermediate 60. The TFA salt was suspended into water and the pH adjusted to ˜7.0 with 10% NaOH. The resulting solids were filtered and dried to yield intermediate 60; 1H NMR (DMSO-d6, 400 MHz) δ7.88-7.85 (m, 2H), 7.48-7.43 (m, 3H), 7.11 (d, 2H, J=8.5), 6.82 (d, 2H, J=8.5), 3.92 (t, 2H, J=6.2), 3.55 (m, 1H), 3.0 (dd, 1H, J=14.3, 4.8), 2.8 (dd, 1H, J=14.3, 7.7), 2.67-2.56 (m, 4H), 2.02-1.96 (m, 2H), 1.13 (t, 3H, J=7.4); low resolution MS (ES+)m/e 392.9 (MH+); TLC Rf=0.44 (4/1, DCM/MeOH).
