Chlorosulfonic acid → 4-(Chlorosulfonyl)-1,3-dimethyl-1H-pyrazole-5-carboxylic acid
Reaction equation
[CH3:1][N:2]1[C:6]([C:7]([O:9]CC)=[O:8])=[CH:5][C:4]([CH3:12])=[N:3]1.[Cl:13][S:14](O)(=[O:16])=[O:15]>>[CH3:1][N:2]1[C:6]([C:7]([OH:9])=[O:8])=[C:5]([S:14]([Cl:13])(=[O:16])=[O:15])[C:4]([CH3:12])=[N:3]1Participants
3
Conditions
- Temperature
- 5 °C
Procedure
Into 200 ml of chlorosulfonic acid, there was added dropwise 50.4 g (0.3 mol) of Ethyl 1,3-dimethyl-5-pyrazole carboxylate under cooling at 5° C. or lower. After heating at 120° C. under stirring for 10 hours, the reaction mixture was poured into ice-water and extracted with ether. After washing with water and drying, evaporation of the solvent gave 49 g of crude 1,3-dimethyl-4-chlorosulfonyl-5-pyrazole carboxylic acid as a solid.
Workup
- temperature