Sodium Carbonate → 5-Chloro-1,3-dimethyl-1h-pyrazole-4-carbonyl chloride

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Reaction Steps

To a solution of 48.5 g of 5-chloro-1,3-dimethyl-1H-pyrazole-4-carbaldehyde in 230 ml of chlorobenzene are added 36 g of sodium carbonate. Subsequently, 3.9 g of 2,2-azoisobutyronitrile (AIBN) are added at 60° C., and, within 4 hours, 24 g of chlorine gas are introduced and a further 6 g of AIBN are added. After the gas introduction has ended, the reaction solution is stirred for a further 30 minutes. The solid is filtered off and washed with a little chlorobenzene. After the solvent has been removed, 5-chloro-1,3-dimethyl-1H-pyrazole-4-carbonyl chloride is obtained in a yield of 74%.

Provenance & Evidence