Hydrazinecarboxylic acid, ethyl ester → 6-(p-Bromophenyl)-1,2,4-triazolo[4,3-b]pyridazin-3(2H)-one

Participants

Reaction Steps

A mixture of 2.69 g. of 6-(p-bromophenyl)-3-chloropyridazine (U.S. Pat. No. 4,092,311), 3.12 g. of ethyl carbazate and 50 ml. of n-butanol is heated at reflux for 16 hours, then cooled and filtered giving an orange solid which is saved. The filtrate is heated at reflux for 23 hours, then chilled in an ice bath and filtered giving more orange solid. The two crops are combined and recrystallized from dimethylformamide, giving 0.65 g. of the desired product as orange crystals, m.p. 348°-350° C. (dec.).

Provenance & Evidence