Reaktionsschritte
1,8-Diazabicyclo[5,4,0]-undec-7-ene (1.8 g, 11.8 mmol) was added to a stirred suspension of 3-(4-aminomethyl-1-oxo-1,3-dihydro-isoindol-2-yl)-piperidine-2,6-dione hydrochloride (1.4 g, 4.5 mmol) in DMF (50 mL). After stirring for 10 minutes, 1-hydroxbenzotriazole (0.7 g, 5.4 mmol) and N—BOC-γ-aminobutyric acid (1.1 g, 5.4 mmol) were added. The reaction was initiated by addition of 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (1.3 g, 6.8 mmol). The mixture was stirred at room temperature overnight. The mixture was concentrated, and the residue was stirred with EtOAc (50 mL) and H2O (40 mL) for 30 minutes. The mixture was filtered, and dried to give (3-{[2-(2,6-dioxo-piperidin-3-yl)-1-oxo-2,3-dihydro-1H-isoindol-4-ylmethyl]-carbamoyl}-propyl-carbamic acid t-butyl ester (1.6 g, 77%) as a white solid: mp 199-201° C.; 1H NMR (DMSO-d6) δ 1.37 (s, 9H, 3CH3), 1.58-1.66 (m, 2H, CH2), 1.99-2.16 (m, 3H), 2.36-2.49 (m, 1H), 2.58-2.64 (m, 1H), 2.86-2.94 (m, 3H), 4.31 (d, J=5.6 Hz, 2H, CH2), 4.38 (d, J=17.3 Hz, 1H), 4.46 (d, J=17.3 Hz, 1H), 5.10-5.18 (dd, J=5.0 and 13.1 Hz, 1H, CH), 6.81 (t, J=5.4 Hz, 1H, NH), 7.48-7.64 (m, 3H, Ar), 8.37 (t, J=5.7 Hz, 1H, NH), 11.02 (s, 1H, NH); 13C NMR (DMSO-d6) δ 22.56, 25.72, 28.23, 31.18, 32.63, 38.95, 46.15, 51.56, 77.04, 121.60, 128.27, 130.55, 131.61, 134.70, 140.06, 155.55, 168.04, 170.97, 171.90, 172.82; Anal. calcd. for C23H30N4O6: C, 60.25; H, 6.59; N, 12.22. Found: C, 60.12; H, 6.55; N, 12.15.
