[H-].[Na+].[OH:3][C:4]1[C:12]2[N:11]=[C:10]([CH3:13])[N:9]([CH3:14])[C:8]=2[CH:7]=[C:6]([C:15]([O:17][CH3:18])=[O:16])[CH:5]=1.Cl[CH:20]1[C:29]2[C:24](=[CH:25][CH:26]=[CH:27][CH:28]=2)[O:23][CH2:22][CH2:21]1>CN(C)C=O>[O:23]1[C:24]2[C:29](=[CH:28][CH:27]=[CH:26][CH:25]=2)[CH:20]([O:3][C:4]2[C:12]3[N:11]=[C:10]([CH3:13])[N:9]([CH3:14])[C:8]=3[CH:7]=[C:6]([C:15]([O:17][CH3:18])=[O:16])[CH:5]=2)[CH2:21][CH2:22]1To a suspension of sodium hydride (60% dispersion in mineral oil, 0.71 g, 18 mmol) in N,N-dimethylformamide (40 mL) was added a suspension of methyl 4-hydroxy-1,2-dimethyl-1H-benzimidazole-6-carboxylate (3.0 g, 14 mmol, WO 2004054984) in N,N-dimethylformamide (40 mL) dropwise under nitrogen atmosphere at room temperature. After stirring for 20 minutes, a solution of 4-chlorochromane (4.6 g, 27 mmol, WO 2000078751) in N,N-dimethylformamide (10 mL) was added at room temperature. The reaction mixture was warmed to 70° C. for 2.5 hours, cooled to room temperature, and stirred for 18 hours at the same temperature. The reaction mixture was quenched with water and extracted with ethyl acetate (250 mL×2). The combined extracts were washed with sodium hydrogencarbonate aqueous solution, ammonium chloride aqueous solution and brine, dried over sodium sulfate, and concentrated in vacuum. The resulting solid was suspended with ethyl acetate and diethyl ether, and collected by filtration to give the title compound as a white solid (2.95 g, 61%):
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