Hydrazine hydrate (1:1) → HCID 178515601, compound

Participants

Reaction Steps

428.4 g of ethyl 3-(4-chloro-2-fluorophenyl)-3-oxopropionate were initially charged in 1400 ml of ethanol. Over a period of 15 min, 92 g of hydrazine hydrate were added dropwise, the mixture was stirred at room temperature overnight, the precipitated solid was filtered off and the filtrate was concentrated to ⅓ of its original volume. The mixture was stirred for another two nights, the resulting solid was filtered off with suction and the filtrate was again concentrated to ⅓ of its original volume. This gave a total of 289.1 g (77.7%) of 3-(4-chloro-2-fluorophenyl)-5-hydroxy-1H-pyrazole as a colorless solid. M.p.: 194° C.

Provenance & Evidence