Hydrochloric Acid → 6-Chloro-7-(4-(2,4-dichlorophenethylcarbamoyl)-phenoxy)chroman-4-carboxylic acid

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Reaction Steps

Ethyl 6-chloro-7-(4-(2,4-dichlorophenethylcarbamoyl)phenoxy)-chroman-4-carboxylate (220 g, 401 mmol) was dissolved in 1.8 L of a 2:1 mixture of THF:EtOH. To the solution was added 4 N NaOH (150 mL, 600 mmol) and the reaction was stirred at ambient temperature for 2 hours. The mixture was concentrated to a solid residue, diluted with 1 L of water and 1 N HCl (700 mL, 700 mmol) was added. The resulting white solids were collected by filtration, washing with 2 L of water. The white solids were dried under high vacuum to give 6-chloro-7-(4-(2,4-dichlorophenethylcarbamoyl)-phenoxy)chroman-4-carboxylic acid (207 g, 99% yield). MS (apci) m/z=520 (M−H).

Provenance & Evidence