HCID 21471655, compound → HCID 15839547, compound

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The crude 1,3-dihydro-1-{1-[1-(6-azido-2-pyrazinecarbonyl)piperidin-4-yl]piperidin-4-yl}-2H-benzimidazol-2-one was hydrogenated under 1 atm. of hydrogen in 20 mL of ethanol over 0.05 g of 5% palladium on carbon. The catalyst was removed by filtration and the filtrate concentrated to dryness under reduced pressure. Preparative thin layer chromatography using 20% methanol/10% conc. NH4OH/70% chloroform gave 35 mg of 1,3-dihydro-1-{1-[1-(6-amino-2-pyrazinecarbonyl)piperidin-4-yl]piperidin-4-yl}-2H-benzimidazol-2-one as a solid: 1H NMR (400 MHz, CDCl3) 8.12 (s, 1H), 8.02 (s, 1H), 7.85 (br s, 1H), 7.19-7.04 (m, 4H), 4.95 (br s, 1H), 4.62 (br s, 1H), 4.2 (br s, 1H), 3.65 (br s, 1H), 3.6-3.2 (m, 4H), 3.15 (m, 2H), 3.03 (m, 1H), 2.82 (m, 1H), 2.45-2.25 (m, 2H), 2.1-1.8 (m, 4H). The dihydrochloride salt was precipitated from chloroform/methanol: Analysis calculated for C21H27N7O2.0.45 CHCl3.0.65 NH4Cl: C: 46.25, H: 5.54, N: 18.38 found C: 46.28, H: 5.92, N: 18.48.

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