2-Bromo-4-trifluoromethylaniline → HCID 68760899, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of ethyl 4-[2,4-dichloro-7-(1-ethylpropyl)-1H-benzimidazol-1-yl]butanoate (Reference Example 33; 2.24 g, 6.63 mmol), 2-bromo-4-trifluoromethylaniline (3.18 g, 13.25 mmol), p-toluenesulfonic acid monohydrate (1.35 g, 7.09 mmol) and xylene (5.0 mL) was stirred at 130° C. for 15 hr. After cooling, the reaction mixture was neutralized with aqueous saturated sodium hydrogen carbonate and extracted with ethyl acetate (×3). The combined organic layer was washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with a 0-15% ethyl acetate/n-hexane gradient mixture to give crude ethyl 4-[2-{[2-bromo-4-(trifluoromethyl)phenyl]amino}-4-chloro-7-(1-ethylpropyl)-1H-benzimidazol-1-yl]butanoate. The crude material (MS Calcd.: 573; Found: 574 (M+H)) was subjected for the next step without further purification. To a solution of the crude material in tetrahydrofuran (15.0 mL) was added lithium borohydride (193.0 mg, 8.86 mmol) at 0° C. The reaction mixture was stirred at room temperature for 2 hr and warmed to 60° C. and stirred for 19 hr. The reaction mixture was quenched with water at 0° C. and extracted with ethyl acetate (×3). The combined organic layer was washed with brine (×1), dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with a 0-20% ethyl acetate/n-hexane gradient mixture to give a mixture contained the title compound. The residue was purified by preparative HPLC to give the title compound as the trifluoroacetic acid salt. The salt was washed with aqueous sodium hydrogen carbonate and extracted with ethyl acetate. The extract was washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo to give the title compound as a colorless powder (110.4 mg, 0.207 mmol, 3.1%(2 steps)).

Provenance & Evidence