Trifluoroacetic acid → 2-((Benzofuran-5-yl)amino)-4-phenethylbenzoic acid

Beteiligte Stoffe

Reaktionsschritte

To toluene 3.0 mL suspension of tert-butyl 2-amino-4-phenethylbenzoate 0.10 g, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl 8 mg, tris(dibenzylideneacetone)dipalladium(0) 3 mg and cesium carbonate 0.22 g was added 5-bromobenzofuran 0.19 g, and it was heated and refluxed for 24 hours. After the reaction mixture was cooled to room temperature, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl 8 mg and tris(dibenzylideneacetone)dipalladium(0) 3 mg were added to it, and it was heated and refluxed for 24 hours. After the reaction mixture was cooled to room temperature, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl 8.0 mg and tris(dibenzylideneacetone)dipalladium(0) 3 mg were added to it, and it was heated and refluxed for 24 hours. After the reaction mixture was cooled to room temperature, insoluble matter was filtrated, and ethyl acetate and 10% citric acid aqueous solution were added to it. The organic layer was separated and collected, dried over anhydrous magnesium sulfate after washing with saturated sodium chloride aqueous solution, and the solvent was removed under reduced pressure. The obtained residue was refined by silica gel column chromatography [Trikonex company, Flash Tube 2008, eluent; hexane:ethyl acetate=20:1] to give tert-butyl 2-((benzofuran-5-yl)amino)-4-phenethylbenzoate. Trifluoroacetic acid 3.0 mL was added to the obtained tert-butyl 2-((benzofuran-5-yl)amino)-4-phenethylbenzoate, and it was stirred at room temperature for 3 hours. The solvent was removed under reduced pressure, the obtained residue was refined by silica gel column chromatography [Trikonex company, Flash Tube 2008, eluent; hexane:ethyl acetate:acetic acid=30:10:1] to give 2-((benzofuran-5-yl)amino)-4-phenethylbenzoic acid 21 mg of white solid.

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