Sodium Hydroxide → 5-ethyl-4-(4-ethyl-1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylic acid

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Reaction Steps

A solution of methyl 5-ethyl-4-(4-ethyl-1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (181 mg, 0.65 mmol) in 6N sodium hydroxide (2.16 ml, 13.0 mmol) and tetrahydrofuran (5.4 ml) was stirred at 70° C. in a sealed tube for 1 h. The resulting solution was cooled and then partitioned between H2O-DCM. The aqueous phase was adjusted to pH ˜4 and then washed several times with DCM. The combined organic fractions were dried over Na2SO4 and concentrated affording 5-ethyl-4-(4-ethyl-1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylic acid (175 mg, 0.65 mmol, 100% yield) as a white foam: LCMS (ES) m/e 265 (M+H)+.

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