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

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Reaction Steps

A solution of methyl 5-methyl-4-[1-methyl-4-(1-methylethyl)-1H-pyrazol-5-yl]-2-thiophenecarboxylate (173 mg, 0.62 mmol) in 6N sodium hydroxide (1 ml, 6.21 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-methyl-4-[1-methyl-4-(1-methylethyl)-1H-pyrazol-5-yl]-2-thiophenecarboxylic acid (148 mg, 0.49 mmol, 79% yield) as a white foam: LCMS (ES) m/e 265 (M+H)+.

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