Reaction Steps
To a stirred mixture of 5-aminomethyl-2-(2,6-dioxo-piperidin-3-yl)-isoindole-1,3-dione hydrochloride (1.00 g, 3.10 mmol) and cyclohexylisocyanate (0.39 g, 3.10 mmol) in THF (35 mL), was added triethylamine (0.88 mL, 6.20 mmol) at room temperature under nitrogen. The mixture was heated to 40° C. for 18 h then cooled to rt. The mixture was filtered and the filtrate diluted with EtOAc (100 mL). The organic layer was washed with dil. aq. HCl (100 mL), water (2×100 mL), dried (MgSO4) and concentrated. The crude product was purified by prep-HPLC (40/60 CH3CN/H2O). The product fractions were combined, concentrated and dried in vacuo to give 1-cyclohexyl-3-[2-(2,6-dioxo-piperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-5-ylmethyl]-urea as a white solid (0.65 g, 77% yield): HPLC: Waters Symmetry C18, 5 μm, 3.9×150 mm, 1 mL/min, 240 nm, 40/60 CH3CN/0.1% H3PO4, 3.16 min (99.05%); mp: 208-210° C.; 1H NMR (DMSO-d6) δ 1.01-1.36 (m, 5H), 1.46-1.83 (m, 5H), 2.00-2.14 (m, 1H), 2.53-2.66 (m, 2H), 2.79-3.01 (m, 1H), 3.34-3.44 (m, 1H), 4.36 (d, J=6.0 Hz, 2H), 5.14 (dd, J=5.3, 12.8 Hz, 1H), 6.00 (d, J=7.9 Hz, 1H), 6.42 (t, J=5.9 Hz, 1H), 7.67-7.79 (m, 2H), 7.87 (d, J=7.6 Hz, 1H), 11.12 (s, 1H); 13C NMR (DMSO-d6) δ 22.01, 24.50, 25.27, 30.93, 33.23, 42.67, 47.97, 48.97, 121.54, 123.39, 129.50, 131.53, 133.07, 149.49, 157.28, 167.05, 167.22, 169.83, 172.73; LCMS: MH=413; Anal Calcd for C21H24N4O5+0.2H2O: C, 60.76; H, 5.90; N, 13.47. Found: C, 60.61; H, 5.74; N, 13.31.
