[Cl:1][C:2]1[CH:3]=[C:4]([CH:12]([CH2:24][CH:25]2[CH2:29][CH2:28][CH2:27][CH2:26]2)[C:13]([NH:15][C:16]2[CH:21]=[N:20][C:19]([CH:22]=O)=[CH:18][N:17]=2)=[O:14])[CH:5]=[CH:6][C:7]=1[S:8]([CH3:11])(=[O:10])=[O:9].[NH:30]1[CH2:36][C:34](=[O:35])[NH:33][C:31]1=[O:32].N1CCCCC1.C(O)(=O)C1C=CC=CC=1>C(O)C>[Cl:1][C:2]1[CH:3]=[C:4]([CH:12]([CH2:24][CH:25]2[CH2:26][CH2:27][CH2:28][CH2:29]2)[C:13]([NH:15][C:16]2[CH:21]=[N:20][C:19]([CH:22]=[C:36]3[C:34](=[O:35])[NH:33][C:31](=[O:32])[NH:30]3)=[CH:18][N:17]=2)=[O:14])[CH:5]=[CH:6][C:7]=1[S:8]([CH3:11])(=[O:9])=[O:10]A solution of 2-(3-chloro-4-methanesulfonyl-phenyl)-3-cyclopentyl-N-(5-formyl-pyrazin-2-yl)-propionamide (prepared as in Example 18, 217 mg, 0.5 mmol), hydantoin (75 mg, 0.75 mmol), piperidine (10 μL, 0.10 mmol), and benzoic acid (6.1 mg, 0.05 mmol) in anhydrous ethanol (30 mL) was heated under reflux for 2 d. The reaction mixture was allowed to cool to 25° C. and then was concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230–400 mesh, 10%–65% ethyl acetate/hexanes) afforded the 2-(3-chloro-4-methanesulfonyl-phenyl)-3-cyclopentyl-N-[5-(2,5-dioxo-imidazolidin-4-ylidenemethyl)-pyrazin-2-yl]-propionamide (84 mg, 33%) as a white solid: LC-MS m/e 518 (MH+).
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