Semicarbazide hydrochloride → 6-chloro-2H,3H-[1,2,4]triazolo[4,3-b]pyridazin-3-one

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Reaction Steps

To a stirring solution of 3 g (20 mmol) of 3,6-dichloropyridazine and 4.5 g (40 mmol) semicarbazide hydrochloride in 100 mL of a 3:1 mixture of ethanol/water was added 5 drops of concentrated hydrochloric acid. The resulting solution was heated to reflux for 24 h under nitrogen then evaporated in vacuo and the resulting solid was recrystallized from ethanol to yield the title compound as a yellow crystalline solid. A similar route to this compound is described in the literature (P. Francavilla, et. al. J. Heterocyclic Chem., 1971, 8, 415-419). LC/MS 171.2 (M+1).

Provenance & Evidence