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

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Reaction Steps

A solution of methyl 5-ethyl-4-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (300 mg, 1.198 mmol) in 6N sodium hydroxide (2.397 ml, 1.198 mmol) and tetrahydrofuran (5.992 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-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylic acid (283 mg, 1.2 mmol, 100% yield) as a yellow oil; LCMS (ES) m/z=236 (M+H)+.

Provenance & Evidence