1,1'-Carbonyldiimidazole → Tert-butyl 4-[2-[2-(difluoromethyl)-4-methoxy-1h-benzimidazol-1-yl]-6-(4-morpholinyl)-8-oxo-7,8-dihydro-9h-purin-9-yl]-1-piperidinecarboxylate

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Reaction Steps

1,1′-Carbonyldiimidazole (689 mg, 4.25 mmol) was added to a solution of the above amine (244 mg, 0.425 mmol) in 1,4-dioxane (25 mL) and the mixture was refluxed under nitrogen for 4.5 hrs. Additional 1,1′-carbonyldiimidazole (689 mg, 4.25 mmol) was added, and the mixture refluxed for additional 17.5 hrs. The mixture was cooled to room temperature and diluted with water. The resulting precipitate was collected by filtration, washed with H2O, and dried. Chromatography on silica, eluting with CH2Cl2/MeOH (100:0 to 97:3), gave tert-butyl 4-[2-[2-(difluoromethyl)-4-methoxy-1H-benzimidazol-1-yl]-6-(4-morpholinyl)-8-oxo-7,8-dihydro-9H-purin-9-yl]-1-piperidinecarboxylate (176 mg, 69%): mp (CH2Cl2/i-Pr2O) 269-272° C.; 1H NMR (CDCl3) δ 10.94 (br s, 1H), 7.73 (dd, J=8.3, 0.3 Hz, 1H), 7.36 (t, J=8.2 Hz, 1H), 7.36 (t, JHF=53.6 Hz, 1H), 6.81 (d, J=7.8 Hz, 1H), 4.49 (tt, J=12.1, 4.1 Hz, 1H), 4.38 (br s, 2H), 4.06 (s, 3H), 3.89 (dd, J=5.6, 3.6 Hz, 4H), 3.82 (dd, J=5.6, 3.7 Hz, 4H), 2.85 (m, 2H), 2.56 (m, 2H), 1.83 (d, J=11.0 Hz, 2H), 1.48 (s, 9H); Anal. Calcd. for C28H34F2N8O5.0.1 i-Pr2O: C, 56.2; H, 5.8; N, 18.3. Found: C, 56.2; H, 5.90; N, 18.0%.

Provenance & Evidence