Acetaldehyde → Methyl 4-[2-[(2,4-dichlorophenyl)amino]-7-(diethylamino)-1H-benzimidazol-1-yl]-3-hydroxybutanoate

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Reaction Steps

To a suspension of methyl 4-{7-amino-2-[(2,4-dichlorophenyl)amino]-1H-benzimidazol-1-yl}-3-hydroxybutanoate (Reference Example 82; 760 mg, 1.85 mmol) in methanol (19 mL) and acetic acid (0.380 mL) was added acetaldehyde (0.692 mL, 11.1 mmol) at 0° C. The resultant mixture was stirred at 0° C. for 30 min. To the reaction mixture was added sodium acetoxyborohydride (2.35 g, 11.1 mmol) at 0° C. After the resultant mixture was stirred at room temperature for 15 hr, the mixture was diluted with aqueous sodium hydrogen carbonate and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue was purified by column chromatography on silica gel eluting with ethyl acetate to give the title compound as a solid (838 mg, 1.80 mmol, 97%).

Provenance & Evidence