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

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl 5-chloro-4-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (300 mg, 1.169 mmol)[prepared according to the procedure of Example 193] in THF (10 ml) was added N-bromosuccinimide (212 mg, 1.19 mmol). The mixture was sealed and heated at 70° C. After 2 h, a solution of 6N NaOH (2.0 ml, 6.0 M, 11.84 mmol) was added in one portion. The resulting mixture stirred for an additional 2 h and was partitioned between DCM-H2O. The pH of the aqueous phase was adjusted to ˜3 and extracted several times with DCM. The combined organic fractions were dried over Na2SO4, concentrated affording the title compound as a colorless oil (105 mg, 28%): LC-MS (ES) m/z=322 (M+H)+.

Provenance & Evidence