Potassium Hydroxide → N-(4-iso-propylbenzenesulfonyl)-alpha-(4-carboxy-2-n-propylphenoxy)-3,4-methylenedioxyphenylacetamide dipotassium salt

Participants

Reaction Conditions

Reaction Steps

A mixture of 204 g (0.345 mol) of the product of Example 139, 420 mL of 1.0N KOH in methanol and 500 mL of water was stirred at 60° C. under a nitrogen atmosphere. After 3 hours TLC analysis (90:10:1 CH2Cl2 -MeOH-NH4OH) indicated that ester hydrolysis was complete. The reaction mixture was cool slightly, then concentrated on a rotary evaporator to a weight of 500 g. 2.5 L of isopropanol was added and the solution reconcentrated to an oil. The residue was flushed with an additional 2-3 L of isopropanol untill crystallization began. The slurry was concentrated to ca 1.5 L and cooled to 30° C., filtered and washed with 300 mL of IPA and 500 mL of ether. The product was dried affording 185 g of semi-pure title compound as a white crystalline solid. A second crop of 17 g was obtained from the filtrate after cooling. The material was recrystallized as follows: 168 g was dissolved in 3 L of absolute ethanol at reflux, filtered hot, and the flask and funnel rinsed with an additional 500 mL of ethanol. 70 mL of water was added and the solution cooled to 0° C. over 2 hr then aged at 0° C. for 6 hr. The product was collected by filtration, washed with ethanol, then air. The yield was 160.8 g of the title compound as a white crystalline solid.

Provenance & Evidence