Hydrochloric Acid → Ethyl 3-[4-(trifluoromethyl)phenyl]-1H-pyrazole-5-carboxylate

Participants

Reaction Steps

To a solution of 4-trifluoromethylacetophenone (10 g, 53.15 mmol) in EtOH (100 mL) was added portionwise sodium ethoxyde (5.43 g, 79.72 mmol) and the mixture was stirred at room temperature during 20 minutes. Dimethyloxalate (8.16 g, 69.09 mmol) was added and the mixture was heated under reflux during 1 hour and then poured into a solution of HCl 1N. After extraction with CH2Cl2, the organic layer was dried over Na2SO4, and concentrated to dryness. The residue was dissolved in EtOH (100 mL), and hydrazine hydrate (3.1 mL, 63.78 mmol) was added dropwise. The mixture was heated under reflux overnight, then poured into water. After extraction with CH2Cl2, the organic layer was dried over Na2SO4, and concentrated to dryness. The solid residue was crystallised from diisopropyloxyde to afford the titled compound as cream crystals (8.42 g, 55.78%).

Provenance & Evidence