3-Chlorobenzoic Acid → 3-[(3-chlorobenzoyl)amino]-N-[2,6-dichloro-4-[[[(3-hydroxyphenyl)methyl]amino]carbonyl]benzoyl]-L-alanine

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Reaction Steps

Diisopropylethylamine (220 mg, 1.7 mmol) was added to a cooled (0° C.) solution of 3-amino-N-[2,6-dichloro-4-[[[(3-hydroxyphenyl)methyl]amino]carbonyl]benzoyl]-L-alanine, methyl ester hydrochloride (Example 75; 135 mg, 0.28 mmol), 3-chlorobenzoic acid (53 mg, 0.34 mmol), HBTU (136 mg, 0.36 mmol), and HOBT (49 mg, 0.36 mmol) in N,N-dimethylformamide (2 mL). The solution was allowed to stir at room temperature for 4 days, and then the solvent was evaporated. Ethyl acetate (50 mL) was added, and the solution was washed with 1 M HCl, saturated aqueous sodium hydrogen carbonate, and brine (10 mL each), and evaporated. Tetrahydrofuran/methanol (3:1; 4 mL) was added, followed by 10% aqueous lithium hydroxide monohydrate (1 mL, 2.38 mmol). The solution was stirred at room temperature overnight, then the solvent was evaporated and the residue was partitioned between ethyl acetate (30 mL) and 1 M HCl (10 mL). The ethyl acetate layer was evaporated and the residue was dissolved in methanol (˜1 mL), purified by HPLC, and lyophilized to give 3-[(3-chlorobenzoyl)amino]-N-[2,6-dichloro-4-[[[(3-hydroxyphenyl)methyl]amino]carbonyl]benzoyl]-L-alanine (81.1 mg, 51%) as a white solid.

Provenance & Evidence