Reaction Steps
Same procedure as above with Z-Trp-NH(CH2)4NHBoc (1.16 g, 2.28 mmol), 10% Pd/C (242 mg) in MeOH/DMF (10 mL, 1/1). After purification by flash chromatography on silica gel (4-25% MeOH/CH2Cl2), Trp-NH(CH2)4NHBoc was isolated as a white foam (701 mg, 82%). 1H NMR (300 MHz, CDCl3) δ 1.39 (m, 4H, 2 CH2), 1.46 (s, 9H, (CH3)3), 3-3.35 (m, 6H, CH2 Trp, 2 CH2N), 3.7 (m, 1H, CHα), 4.71 (m, 1H, NHBoc), 7.05 (d, J=2 Hz, 1 aromatic H), 7.1 (t, J=7.7 Hz, 1 aromatic H), 7.2 (m, 2H, 1 aromatic H, NH amide), 7.38 (d, J=7.9 Hz, 1 aromatic H), 7.65 (d, J=7.9 Hz, 1 aromatic H), 8.94 (broad s, 1H, NH indole). 13C NMR (75 MHz, CDCl3) δ 26.9, 27.6, 30.8 (2 CH2, CH2 Trp), 28.5 ((CH3)3), 38.7, 40.3 (CH2NHCO, CH2NHBoc), 55.6 (CHα), 79.3 (C(CH3)3), 111.3, 111.4, 118.9, 119.5, 122, 123.3, 127.6, 136.4 (8 aromatic C), 156.2 (CO carbamate), 174.8 (CO amide).
