compound A424P. Same procedure as above with Trp-NHPh (67.6 mg, 0.242 mmol), N-Boc-Tyr(Bn)-Leu-OH (117 mg, 0.242 mmol), EDC (49 mg, 0.25 mmol) and HOBt (35 mg, 0.25 mmol) in CH2Cl2/DMF (3.6 mL, 1/1). The crude residue was dissolved in ether and precipitated with heptane to give a beige solid (135.6 mg, 75%). 1H NMR (300 MHz, DMSO-d6) δ 0.83 (d, 3H, J=6.4 Hz, CH3), 0.87 (d, 3H, J=6.4 Hz, CH3), 1.22-1.44 (m, 2H, CH2 Leu), 1.30 (s, 9H, (CH3)3), 1.44 (m, 1H, CH Leu), 2.46-2.89 (m, 2H, CH2), 3.13 (m, 2H, CH2), 4.12 (m, 1H, CHα), 4.38 (m, 1H, CHα), 4.70 (m, 1H, CHα), 5.02 (s, 2H, CH2 (Bn)), 6.87-7.58 (m, 20H, 19 aromatic H and NH Boc), 7.94 (d, J=8.2 Hz, 1H), 8.17 (d, J=7.5 Hz, 1H), 10.0 (s, 1H, NH), 10.83 (s, 1H, NH). 13C NMR (75 MHz, DMSO-d6) δ 21.5, 23.1, 23.9 (CH—(CH3)2), 27.7 (CH2 Trp), 28.1 ((CH3)3), 36.2, 40.9 (CH2 Tyr, CH2 Leu), 50.9, 54.1, 55.7 (CHα Tyr, Leu, Tip), 69.0 (CH2 (Bn)), 78.0 (C(CH3)3), 109.6, 111.2, 114.2, 118.2, 118.4, 119.3, 120.8, 123.3, 123.4, 127.3, 127.6, 127.7, 128.3, 128.6, 130.1, 130.3, 135.9, 137.2, 138.8 (25 aromatic C), 155.2, 156.8 (Car-O, CO carbamate), 170, 171.6, 171.9 (3 CO amide). Anal. Calcd. for C44H51N5O6: C, 70.85; H, 6.89; N, 9.39. Found: C, 70.52; H, 7.10; N, 9.33.
