Acetone → 2-(4-Bromo-3,5-dimethyl-1H-pyrazol-1-yl)-2-methylpropanoic acid

Participants

Reaction Steps

To a cold (0° C.), well stirred suspension of NaOH (1.6 g, 40 mmoles) and 4-bromo-3,5-dimethylpyrazole (1.75 g, 10 mmoles) in acetone (100 mL), was added 2-(trichloromethyl)-propan-2-ol (3.54 g, 20 mmoles)/portion-wise over 1 hour. The mixture was allowed to warm to room temperature overnight. The solvent was evaporated under reduced pressure. The residue was dissolved in water (100 mL) and washed with ether (50 mL). The aqueous phase was separated and acidified with conc. HCl to pH=3. The mixture was extracted with CH2Cl2 (3×50 mL) and the combined organics dried over Na2SO4. A colorless oil was obtained after the removal of the solvent under reduced pressure. MS(DCI+) m/z 263 (M+H)+.

Provenance & Evidence