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

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Reaction Steps

A solution of methyl 4-(1,4-dimethyl-1H-pyrazol-5-yl)-5-ethyl-2-thiophenecarboxylate (143 mg, 0.54 mmol) in 6N sodium hydroxide (0.90 ml, 5.41 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 4-(1,4-dimethyl-1H-pyrazol-5-yl)-5-ethyl-2-thiophenecarboxylic acid (136 mg, 0.54 mmol, 100% yield) as a yellow oil: LCMS (ES) m/e 251 (M+H)+.

Provenance & Evidence