Acetic Acid → tert-Butyl 3-(3,5-dichlorophenyl)-1H-pyrazole-5-carboxylate

Reaction equation

[Cl:1][C:2]1[CH:3]=[C:4]([C:9](=O)[CH2:10][C:11](=O)[C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH:5]=[C:6]([Cl:8])[CH:7]=1.[NH2:21][NH2:22].C(O)(=O)C>C(O)C>[Cl:1][C:2]1[CH:3]=[C:4]([C:9]2[CH:10]=[C:11]([C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[NH:22][N:21]=2)[CH:5]=[C:6]([Cl:8])[CH:7]=1

Participants

Procedure

To a solution of the product from step C (6.8 g, 21.7 mmol) in 125 mL of ethanol was added hydrazine (0.75 mL, 23.9 mmol) and 10 mL of glacial acetic acid. The reaction mixture was stirred at ambient temperature for 16 h then was concentrated in vacuo and the residue suspended in ethyl acetate. The organic layer was washed successively with two portions of saturated aqueous sodium bicarbonate solution and one portion of brine. The organic layer was dried over magnesium sulfate, and concentrated in vacuo to provide the title compound as a pale yellow solid which was used without further purification.