Water → 4-Benzoyl-4-chloro-2,5-dimethyl-2,4-dihydro-3H-pyrazol-3-one

Reaction equation

[CH3:1][N:2]1[C:6](=[O:7])[C:5]([C:8](=[O:15])[C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=2)=[C:4]([CH3:16])[NH:3]1.S(Cl)([Cl:20])(=O)=O.O>C1C=CC=CC=1>[CH3:1][N:2]1[C:6](=[O:7])[C:5]([Cl:20])([C:8](=[O:15])[C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=2)[C:4]([CH3:16])=[N:3]1

Participants

Procedure

To a solution of 2.16 g of 1,3-dimethyl-4-benzoyl-5-pyrazolone in 20 ml of dry benzene was added 1.62 g of sulfuryl chloride and the mixture was stirred at room temperature for 4 hours. After completion of the reaction, water was added to the reaction mixture and after shaking an organic layer was separated. The organic layer was washed successively with a saturated aqueous solution of sodium hydrogencarbonate and water, dried over anhydrous sodium sulfate and the solvent was distilled off from the solution. The so obtained residue was recrystallized from n-hexane to give 0.2 g of the desired product melting at 70.5° - 72° C. (Yield 7.6%)