Hydrochloric Acid → 3-Benzo[b]thiophen-2-yl-4-fluoro-1H-5-indazolecarboxylic Acid

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Reaction Conditions

Reaction Steps

To a solution of 152 mg of 3-benzo[b]thiophen-2-yl-4-fluoro-1H-5-indazolecarboxylic acid methyl ester obtained in Production Example II-13-f in a mixture of 2 ml of tetrahydrofuran and 2 ml of methanol was added 1 ml of 5 N aqueous sodium hydroxide solution, and the mixture was stirred at 55° C. for 2.5 hours. After standing to cool, 5.5 ml of 1 N hydrochloric acid was added and the mixture was extracted with ethyl acetate. The organic layer was sequentially washed with water and brine, dried over anhydrous magnesium sulfate and the solvent was evaporated. The crude product was recrystallized from tetrahydrofuran-ethyl acetate, to give 104 mg of the title compound as pale red crystals. 1H-NMR (400 MHz, DMSO-D6) δ 7.36-7.43 (2H, m), 7.47 (1H, d, J=8.8 Hz), 7.88 (1H, dd, J=6.4, 8.8 Hz), 7.95-8.00 (2H, m), 8.03 (1H, s), 13.16 (1H, s).

Provenance & Evidence