[CH3:1][C:2](C)([O-])C.[K+].[Cl:7][C:8]1[C:16]2[N:15]=[C:14]3[N:17]([C:21]4[C:22]([CH3:30])=[N:23][C:24]([O:28][CH3:29])=[N:25][C:26]=4[CH3:27])[CH2:18][CH2:19][CH2:20][N:13]3[C:12]=2[C:11]([CH2:31][C:32]#[N:33])=[CH:10][CH:9]=1.C(I)C>O1CCCC1.[Cl-].[NH4+]>[Cl:7][C:8]1[C:16]2[N:15]=[C:14]3[N:17]([C:21]4[C:22]([CH3:30])=[N:23][C:24]([O:28][CH3:29])=[N:25][C:26]=4[CH3:27])[CH2:18][CH2:19][CH2:20][N:13]3[C:12]=2[C:11]([CH:31]([CH2:1][CH3:2])[C:32]#[N:33])=[CH:10][CH:9]=1Potassium t-butoxide (908 mg, 8.09 mmol) was added to a stirred solution of [9-chloro-1-(2-methoxy-4,6-dimethylpyrimidin-5-yl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-yl]acetonitrile (1.41 g, 3.68 mmol) and ethyl iodide (1.43 g, 9.20 mmol) in tetrahydrofuran (18 mL) at 0° C., and the mixture was stirred at 0° C. for 50 min. The mixture was diluted with aqueous saturated ammonium chloride, and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo. The residue was purified by flash column chromatography on silica gel eluting with a 70-100% ethyl acetate/n-hexane gradient mixture. The filtrate was concentrated in vacuo to give the title compound as a colorless solid (1.20 g, 2.92 mmol, 79%).
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