Reaction Steps
To a solution of 14 (1.48 g, 1.52 mmol) in THF (30 mL), was added dimethyl amine (15.2 mL, 2M in THF, 30.4 mmol) at 0° C. This reaction was allowed to reach room temperature and stirred for 2 h. At this time, the reaction mixture was concentrated in vacuo. To the yellowish solid was added DCM (30 mL) and DMF (5 mL). To this solution, was added Boc-Lys(Z)—OH (0.608 g, 1.60 mmol), then HOBt (0.216 g, 1.60 mmol), then EDC.HCl (0.3063 g, 1.60 mmol). This solution was allowed to stir for 8 h at which time the organic solution was washed with 1N HCl (3×15 mL), then saturated NaHCO3 (3×15 mL), and finally H2O (3×15 mL). The organic layer was dried over MgSO4 and concentrated in vacuo to yield a white solid. Column chromatography (2% MeOH, CHCl3) afforded the product 15 (1.0 g, 59% yield): 1H NMR (500 MHz, CDCl3) δ 8.15 (br s, 1H), 8.03 (br s, 1H), 7.88 (br s, 1H), 7.45-7.28 (m, 10H), 7.12 (br s, 1H), 6.65 (br s, 1H), 5.08 (s, 1H), 4.45-4.35 (m, 3H), 4.05 (br s, 1H), 3.67 (s, 3H), 3.11 (br s, 1H), 3.01 (br s, 1H), 1.90-1.60 (m, 8H), 1.60-1.38 (m, 44); 13C NMR (125 MHz, CDCl3) δ 173.3, 173.2, 172.7, 172.3, 157.2, 156.6, 138.4, 129.0, 128.4, 79.0, 78.1, 66.0, 55.7, 53.8, 53.4, 53.0, 52.2, 41.1, 40.9, 40.8, 32.7, 32.5, 31.6, 29.8, 29.6, 28.6, 23.7, 23.5; ESMS (FAB) m/z calcd for C66H88N8O15 (M+H)+ 1113.65, found 1113.52.
