3,5-Dichloro-4-hydroxybenzoic acid → 2,6-Dichloro-4-[[[[3-[[(1,1-dimethylethyl)dimethyl-silyl]oxy]phenyl]methyl]amino]carbonyl]phenol

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Reaction Steps

A solution of 3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]benzenemethanamine (Example 8; 5.80 g, 24.5 mmol) in dry dichloromethane (20 mL) was added to a cooled (0° C.) suspension of 3,5-dichloro-4-hydroxybenzoic acid (4.2 g, 20.4 mmol) and BOP reagent (9.80 g, 22.3 mmol) in dry dichloromethane (50 mL). Diisopropylethylamine (10.6 mL, 60.9 mmol) was added slowly, and the cooling bath was removed. The solution was stirred at room temperature for 5 h, then the solvent was evaporated and the residue was dissolved in ethyl acetate. The solution was washed with 1 M HCl (2×100 mL), saturated aqueous sodium hydrogen carbonate (100 mL), and brine (100 mL), dried (MgSO4), filtered, evaporated, and chromatographed (30% ethyl acetate/hexanes) to give 2,6-dichloro-4-[[[[3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]phenyl]methyl]amino]carbonyl]phenol (7.50 g, 87%) as a white solid.

Provenance & Evidence