4-Bromo-2-methylaniline → Ethyl 4-[2-[(4-bromo-2-methylphenyl)amino]-4-chloro-7-(1-ethylpropyl)-1H-benzimidazol-1-yl]butanoate

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Reaction Conditions

Reaction Steps

A mixture of ethyl 4-[2,4-dichloro-7-(1-ethylpropyl)-1H-benzimidazol-1-yl]butanoate (Reference Example 33; 2.00 g, 5.39 mmol), 4-bromo-2-methylaniline (3.01 g, 16.2 mmol), p-toluenesulfonic acid monohydrate (1.10 g, 5.78 mmol) and xylene (15 mL) was stirred at 150° C. for 20 hr. The mixture was neutralized with aqueous sodium hydrogen carbonate 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 0-15% ethyl acetate/n-hexane gradient mixture. The filtrate was concentrated in vacuo to give the solid, which was recrystallized from ethyl acetate/n-hexane to give the title compound as a colorless crystal (2.11 g, 4.05 mmol, 75%).

Provenance & Evidence