Hydrochloric Acid → 1-(ethoxycarbonyl)-3-[(4-chloromethyl-benzoyl)amino]-1H-thieno[2,3-c]pyrazole-5-carboxylic acid

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Reaction Conditions

Reaction Steps

5-tert-butyl 1-ethyl 3-[(4-chloromethyl-benzoyl)amino]-1H-thieno[2,3-c]pyrazole-1,5-dicarboxylate (8.2 g) was added to a solution of hydrochloric acid in dioxane (88 mL, 4N solution). The resulting mixture was stirred at 50° C. for 2 hours. Afterward, volatiles were removed by evaporation under reduced pressure and the residue triturated with diethyl ether, filtered, extensively washed with diethyl ether and dried under vacuum at 40° C. to give 5.7 g of the title compound, used in the next step without further purification.

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