N-bromobutanimide → HCID 66869262, compound

Participants

Reaction Steps

Add a solution of NaOH (15%, 6 mL) to a solution of 4-ethoxycarbonyl-3-(4-fluorophenyl)-1-tert-butyl-1H-pyrazole (0.350 g, 1.2 mmol) in MeOH (3 mL) and then add acetonitrile (1 mL). Stir the mixture at 50° C. for 3 h, cool to RT and add HCl (10%) until the pH=3. Extract the mixture with EtOAc (3×100 mL). Combine the organic layers and wash with brine (100 mL), dry (MgSO4) and concentrate to provide 4-carboxy-3-(4-fluorophenyl)-1-tert-butyl-1H-pyrazole as a yellow solid (0.320 g), MS (ESi+): 229.1 (M+H)+. Next treat a solution of 4-carboxy-3-(4-fluorophenyl)-1-tert-butyl-1H-pyrazole (0.315 g, 1.2 mmol) in DMF (15 mL) previously degassed with N-bromosuccinimide (0.235 g, 1.32 mmol) at RT for about 18 h. Dilute the mixture with EtOAc (80 mL) and wash with cooled water (5×10 mL), dry (MgSO4), and concentrate to provide the desired compound as yellow solid (0.262 g, 73% yield).

Provenance & Evidence