Hydrazine hydrate (1:1) → HCID 178515597, compound

Participants

Reaction Steps

970 g of methyl 3-(2,4-dichlorophenyl)-3-oxopropionate were initially charged in 4000 ml of ethanol. Over a period of 15 min, 201 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 filtrate 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 714.2 g (79.4%) of 3-(2,4-dichlorophenyl)-5-hydroxy-1H-pyrazole as a colorless solid. M.p.: 198° C.

Provenance & Evidence