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

Participants

Reaction Conditions

Reaction Steps

NBS (1.243 g, 6.98 mmol) was added in portions to a 150 mL sealed tube reactor containing methyl 5-chloro-4-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (1.47 g, 5.73 mmol) [Prepared according to the procedure of Example 151] in Tetrahydrofuran (THF) (40 ml) at room temperature. The mixture was heated to 70° C. for 1 h. 6N NaOH (20 ml, 120 mmol) was then added and the mixture stirred at 70° C. for an additional 2 h. The mixture was partitioned between CHCl3 and H2O, the organic layer dried with Na2SO4 and concentrated affording the title compound which was used without further purification (385 mg, 1.4 mmol, 30%): LC-MS (ES) m/z=302 (M+H)+.

Provenance & Evidence