Oxopropylation of 4,5-dihalopyridazin-6-ones with chloroacetone afforded the corresponding 1-(2-oxo-propyl) derivatives. Reaction of title compound with nucleophiles such as amines, alkoxides were investigated. In addition, selective reduction of 3-nitro-1-(2-oxopropyl)pyridazin-6-ones with iron/ammonium chloride in two phase solutions or zinc in acetic acid gave the corresponding 3-amino or 3-hydroxyimino derivatives.