Dimethylformamide → (S)-3-methyl-2-(4'-{[3-methyl-4-(3-nitro-phenyl)-benzofuran-2-carbonyl]-amino}-biphenyl-4-sulfonylamino)-butyric acid methyl ester

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Reaction Steps

To 100 mg (0.34 mmol) of 3-methyl-4-(3-nitro-phenyl)-benzofuran-2-carboxylic acid was added 2 mL of oxalyl chloride and the resulting mixture was refluxed for 2 h in the presence of a catalytic amount of DMF, then the excess oxalyl chloride was removed under vacuum. The residue was dissolved in 1 mL of dichloromethane and was added to a mixture of 183 mg (0.5 mmol) of (S)-2-(4′-amino-biphenyl-4-sulfonylamino)-3-methyl-butyric acid methyl ester and 2 mL of pyridine in an ice/water bath. The mixture was stirred at room temperature overnight. All the solvents were removed under vacuum. Column chromatography on silica gel gave 41 mg of (S)-3-methyl-2-(4′-{[3-methyl-4-(3-nitro-phenyl)-benzofuran-2-carbonyl]-amino}-biphenyl-4-sulfonylamino)-butyric acid methyl ester as white solid.

Provenance & Evidence