Potassium Hydroxide → 4-[1-(1,3-Benzodioxol-5-yl)-2-oxo-2-[(4-propan-2-ylphenyl)sulfonylamino]ethoxy]-3-propylbenzoic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of 205 g (0.345 mol) of the product of Example 6, 425 mL of 1.0N KOH in methanol and 500 mL of water was stirred at 60° C. under a nitrogen atmosphere. After 1.75 hours TLC analysis (90:10:1 CH2Cl2 -MeOH-NH4OH) indicated that ester hydrolysis was complete. The reaction mixture was cooled slightly, then concentrated on a rotary evaporator. The concentrate was acidified with 400 mL of 2N HCl and extracted first with 6 L of ether-EtOAc-CH2Cl2 4:1:1, then with 3 L of 1:2 EtOAc-CH2Cl2. The organic layers were washed with 250 mL of 2N HCl, then with 3×500 mL of water, dried with magnesium sulfate, filtered, and concentrated, during which, the product began to crystallize. The solution was concentrated to a white sluury of ca. 750 mL, diluted with 1 L of hexanes, cooled to 0° C., aged 1 hr then filtered. The product was air dried affording 170.0 g (91% yield) of the title compound as a white crystalline solid.

Provenance & Evidence