Hydrochloric Acid → 6,7-Dichloro-5-((dimethylamino)sulfonyl)-2,3-dihydro-2-benzofurancarboxylic acid

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Reaction Steps

To a solution of 1 g of ethyl 5-(N,N-dimethylsulfamoyl)-6,7-dichloro-2,3-dihydrobenzofuran-2-carboxylate (Ia-1) dissolved in 9 ml of tetrahydrofuran is added 14 ml of 15% aqueous potassium carbonate and the mixture stirred for 72 hours at room temperature. The reaction mixture is condensed under reduced pressure to leave residue, which is made acid (pH 5.0) with 10% hydrochloric acid and extracted with ethyl acetate. The organic layer is dried and evaporated under reduced pressure to leave an oil, which is then recrystallized from either to give 0.868 g of 5-(N,N-dimethylsulfamoyl)-6,7-dichloro-2,3-dihydrobenzofuran-2-carboxylic acid (I b-28), yielded in 94%, m.p. 154° C.

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