Hydrochloric Acid → 7-(3-Ethoxybenzyloxy)-1,1-dioxo-2,3-dihydro-1-benzothiepine-4-carboxylic acid

関与物質

反応条件

反応手順

To methyl 7-(3-ethoxybenzyloxy)-1,1-dioxo-2,3-dihydro-1-benzothiepine-4-carboxylate (298 mg) dissolved in THF-methanol (10-5 ml) was added a 2 M aqueous solution of potassium carbonate (0.75 ml), and the resulting mixture was stirred at 60° C. for 16.5 hours. The reaction mixture was treated with 1 N hydrochloric acid to bring the pH to 2. The resulting mixture was extracted with ethyl acetate, and the organic layer was dried with anhydrous magnesium sulfate. After concentration under reduced pressure to remove the solvent, the precipitated crystals were washed with hexane-ethyl acetate to obtain 7-(3-ethoxybenzyloxy)-1,1-dioxo-2,3-dihydro-1-benzothiepine-4-carboxylic acid (45 mg) as white crystals. The mother liquor was concentrated under reduced pressure to obtain 7-(3-ethoxybenzyloxy)-1,1-dioxo-2,3-dihydro-1-benzothiepine-4-carboxylic acid (340 mg) as a brown oil. This compound was used in the next reaction without further purification.

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