Hydrochloric Acid → 3-Anilino-4-acetyl-5-methylpyrazole

Participants

Reaction Steps

50 g of 4-phenylthiosemicarbazide is suspended in 300 ml of tetrahydrofuran and 0.5 ml of concentrated HCl is added. Then 40.4 g of 3-chloroacetyl acetone is allowed to run in all at once and the whole is cooled with an ice-bath. After 12 hours' stirring, the precipitate formed is suction filtered, washed with acetone and then boiled in a water/acetone mixture (1:1). This hot solution is filtered off from the sulfur and neutralized with aqueous ammonia solution. The product is then suction filtered and recrystallized from acetone; m.p. 246°-247° C.

Provenance & Evidence