Reaction Steps
To a stirred suspension of 4-aminomethyl-2-(2,6-dioxo-piperidin-3-yl)-isoindole-1,3-dione hydrochloride (0.7 g, 2.2 mmol) in acetonitrile (60 mL), was added 1,8-diazabicyclo[5,4,0]undec-7-ene (1.2 g, 7.8 mmol). After stirring for 10 minutes, 1-hydroxybenzotriazole (0.4 g, 2.6 mmol) and 4-pyridylacetic acid hydrochloride (0.4 g, 2.4 mmol) were added, followed by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.6 g, 3.2 mmol). The mixture was stirred at room temperature overnight. Solvent was removed in vacuo, and the residue was purified by ISCO silica gel flash chromatography (Eluent: CH3OH: CH2Cl2 3:97) to afford N-[2-(2,6-dioxo-piperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-ylmethyl]-2-pyridin-4-yl-acetamide (0.4 g, 50%) as white solid: mp 294-296° C.; HPLC: Waters Symmetry C-18, 3.9×150 mm, 5 micro, 1 mL/min, 240 nm, 40/60 (CH3CN/H2O): tR=0.87 min. (98%); 1H NMR (DMSO-d6) δ 2.02-2.07 (m, 1H), 2.52-2.96 (m, 2H), 2.84-2.96 (m, 1H), 3.59 (s, 2H), 5.12-5.18 (dd, J=5.2 and 12.7 Hz, 1H), 7.31 (d, J=5.5 Hz, 2H), 7.64-7.70 (m, 1H), 7.79-7.84 (m, 2H), 8.50 (d, J=5.6 Hz, 2H), 8.77 (t, J=5.8 Hz, 1H), 11.14 (s, 1H); 13C NMR (DMSO-d6) δ 21.95, 30.90, 37.91, 41.27, 48.83, 121.96, 124.54, 127.17, 131.53, 133.30, 134.71, 138.88, 144.92, 149.37, 166.88, 167.41, 169.33, 169.78, 172.73; Anal. Calcd. for C21H18N4O5: C, 62.07; H, 4.46; N, 13.79. Found: C, 61.77; H, 4.39; N, 13.59.
