Reaction Steps
3,5-Diiodoaniline [Dininno, F.; Guthikonda, R. N.; Schmitt, S. M. 1994 U.S. Pat. No. 5,292,879 A] (1 g, 2.90 mmol), 6-(2-Trimethylsilanyl-ethoxycarbonylamino)-hexanoic acid (1 g, 3.77 mmol) in DMF (12 ml) were added DIPEA (0.9 ml, 5.8 mmol) and HATU (1.65 g, 4.35 mmol). The mixture was stirred for overnight at room temperature. The reaction mixture was diluted with Et2O. To the mixture was added sat.NaHCO3 and then separated. The aqueous phase was extracted with Et2O (3×40 ml). The combined extraction were washed with 5% HCl (30 ml), H2O (50 ml), sat.NaHCO3 (30 ml), and Brine (30 ml), and finally dried over MgSO4, filtered and concentrated in vacuo. The crude was purified by silica gel column with (Hexane:EtOAc=6:4) to afford 21 (1 g, 59%) as a colorless powder. 1H NMR (300 MHz,(CD3)2SO): δ 0.09 (S, 9H), 0.84 (t, J=2.1 Hz, 2H), 1.34 (m, 2H), 1.40 (m, 2H), 1.50 (m, 2H), 2.41 (t, J=1.8 Hz, 2H), 2.47 (m, 2H), 2.89 (m, 2H), 4.01 (t, 2H), 6.92 (bt,1H), 7.68 (m, 1H), 7.99 (m, 2H); 13C NMR (75 MHz, (CD3)2SO): 6-0.72, 18.0, 25.2, 26.4, 29.9, 36.9, 61.9, 96.4, 127.0, 139.0, 142.3, 156.9, 172.2; IR (film): 3326, 2853, 2361, 1687, 1541, 1450, 1249, 837 cm−1; MS:(ESI)) [M+Na]+ 624.9
