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

Participants

Reaction Steps

A solution of methyl 4-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (3 g, 13.50 mmol) in 6N sodium hydroxide (22.50 ml, 135 mmol) and tetrahydrofuran (27.0 ml) was stirred in a sealed tube at 70° C. After 1 h, the solution was partitioned between H2O-DCM and the pH of the aqueous layer was adjusted to ˜3. The aqueous layer was washed several times with DCM and the combined organic fractions were dried over Na2SO4, concentrated affording 4-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylic acid (2.8 g, 13.45 mmol, 100% yield) as a yellow solid which was used directly without further purification: LCMS (ES) m/e 209 (M+H)+.

Provenance & Evidence