4-Bromo-5-(4′-hydroxymethyltriazolyl)pyridazin-3-one and its derivatives

4-Bromo-5-(4-hydroxymethyltriazolyl)pyridazin-3-ones have been obtained for the first time by the reaction of 5-azido-4-bromopyridazin-3-ones with propargyl alcohol. They have been converted into 4-bromo-5-(4-halogenomethyltriazolyl)pyridazin-3-ones.