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

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Reaction Steps

A solution of methyl 5-methyl-4-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (250 mg, 1.06 mmol) [Prepared in Example 99] in 6N sodium hydroxide (1.76 ml, 10.6 mmol) and tetrahydrofuran (5.290 ml) was stirred at 70° C. in a sealed tube for 1 h. The resulting solution was cooled and 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-1H-pyrazol-5-yl)-2-thiophenecarboxylic acid (151 mg, 0.68 mmol, 64% yield) as a white solid; LCMS (ES) m/z=223 (M+H)+.

Provenance & Evidence