Ethanol → 1-(2,4-Dichlorophenyl)-1H-pyrazol-4-ol

Reaction equation

[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[CH:5]=[CH:4][C:3]=1[NH:9][N:10]=[C:11](CCl)[CH:12]=[O:13].[OH-].[Na+].[CH2:18](O)C>O>[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[CH:5]=[CH:4][C:3]=1[N:9]1[CH:18]=[C:12]([OH:13])[CH:11]=[N:10]1

Participants

Procedure

27.0 g of 3-chloropyruvaldehyde 2,4-dichlorophenylhydrazone is suspended in 100 ml of ethanol. To the suspension is added at room temperature 12 g of sodium hydroxide dissolved in 10 ml of water. After stirring the mixture for 2 hours ethanol is distilled off, and water is added to the resultant residue to dissolve it. Insolubles are removed by filtration, and the filtrate is neutralized with glacial acetic acid. The precipitate is recovered by filtration, washed with water and dried. Recrystallization from toluene results in 17.3 g of the subject compound in the yield of 87%. m.p. 148° to 149° C.