Diisopropylethylamine → (S)-2-{4'-[(4-methoxy-3,5-dimethyl-benzofuran-2-carbonyl)-amino]-biphenyl-4-sulfonylamino}-3-methyl-butyric acid tert-butyl ester

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Reaction Steps

To 45 mg (0.2 mmol) of 4-methoxy-3,5-dimethyl-benzofuran-2-carboxylic acid was added 124 mg (1.5 eq) of (S)-2-(4′-amino-biphenyl-4-sulfonylamino)-3-methyl-butyric acid tert-butyl ester, BOP (106 mg, 1.2 eq), N,N-diisopropylethylamine (31 mg, 1.2 eq) and 2 mL of DMF. The mixture was stirred at room temperature for 24 h. Brine was added and the mixture was extracted with ethyl acetate. The combined organic solution was washed with 2N HCl and water. Removal of the solvent from the organic solution gave the crude product, which was purified by column chromatography on silica gel to give 89 mg of (S)-2-{4′-[(4-methoxy-3,5-dimethyl-benzofuran-2-carbonyl)-amino]-biphenyl-4-sulfonylamino}-3-methyl-butyric acid tert-butyl ester as an off-white solid.

Provenance & Evidence