Sulfuryl chloride → 5-t-Butyl-4-chloro-3-propionylaminopyrazole

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Reaction Steps

5.8 g (0.03 mole) of 5-t-butyl-3-propionylaminopyrazole prepared in Example 5 was dispersed in 30 ml of chloroform, and the dispersion was stirred while adding dropwise thereto sulfuryl chloride. The mixture was further heated under reflux conditions for one hour, and the solvent was distilled off. To the residue was added a sodium bicarbonate aqueous solution whereby crystals were precipitated. The crystals were collected by filtration, washed with water and then dried to obtain 3.9 g of 5-t-butyl-4-chloro-3-propionylaminopyrazole. This product was recrystallized from hydrous methanol and found to have a melting point of 136° to 137° C.

Provenance & Evidence