[Cl:1][C:2]1[CH:25]=[C:24]([Cl:26])[CH:23]=[C:22]([CH3:27])[C:3]=1[O:4][C:5]1[N:9]([CH3:10])[C:8]2[C:11]([CH:17]([CH2:20][CH3:21])[CH2:18][CH3:19])=[CH:12][CH:13]=[C:14]([CH:15]=O)[C:7]=2[N:6]=1.[NH:28]1[CH2:32][CH2:31][CH2:30][CH2:29]1.C(O)(=O)C.C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+]>C(=O)(O)[O-].[Na+].C(OCC)(=O)C>[Cl:1][C:2]1[CH:25]=[C:24]([Cl:26])[CH:23]=[C:22]([CH3:27])[C:3]=1[O:4][C:5]1[N:9]([CH3:10])[C:8]2[C:11]([CH:17]([CH2:20][CH3:21])[CH2:18][CH3:19])=[CH:12][CH:13]=[C:14]([CH2:15][N:28]3[CH2:32][CH2:31][CH2:30][CH2:29]3)[C:7]=2[N:6]=1To a mixture of 2-(2,4-dichloro-6-methylphenoxy)-7-(1-ethylpropyl)-1-methyl-1H-benzimidazole-4-carbaldehyde (93 mg, 0.23 mmol), pyrrolidine (33 mg, 0.46 mmol), acetic acid (0.5 ml) and ethyl acetate (1.5 ml) was added sodium triacetoxyborohydride (244 mg, 1.15 mmol) and the reaction mixture was stirred at room temperature for 1 h. The residue was diluted with aqueous saturated sodium bicarbonate and extracted with ethyl acetate. The extracts were washed with water, dried over magnesium sulfate and concentrated in vacuo. The residue was purified by column chromatography on alumina with a 5% ethyl acetate/n-hexane to give 100 mg (0.22 mmol, 94%) of the title compound as a white powder.
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