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

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Reaction Steps

To 60 mg (0.24 mmol) 3-methyl-4-phenyl-benzofuran-2-carboxylic acid was added 1 mL of oxalyl chloride and the mixture was refluxed for 1 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 129 mg (0.36 mmol) of (S)-2-(4′-amino-biphenyl-4-sulfonylamino)-3-methyl-butyric acid methyl ester, 87 mg (0.714 mmol) of 4-(dimethylamino)pyridine and 2 mL of 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 (29% yield) of (S)-3-methyl-2-{4′-[(3-methyl-4-phenyl-benzofuran-2-carbonyl)-amino]-biphenyl-4-sulfonylamino}-butyric acid methyl ester as white solid.

Provenance & Evidence