Some Conventional and Convenient Process for Functionalization of 6-Phenyl-4,5-Dihydropyridazinone Compounds

The pyridazinone derivatives, particularly those bearing substituted different group or atom at a different position, have attracted considerable attention due to their characteristic pharmacological and other anticipated activities. These activities promoted the synthesis of a large number of substituted pyridazinone derivatives in order to explore the usefulness of this heterocyclic system. In the present review, various synthetic methods have been studied for the synthesis of substituted pyridazinone derivatives. The behaviour of the pyridazinone toward formaldehyde/piperidine, ethyl chloroacetate, chloroacetic acid, benzene sulfonyl chloride, bromine/acetic acid and aromatic aldehydes has also been studied. However, the reactions of the chloro derivative resulting from the reaction of pyridazinone with phosphorus oxychloride (POCl₃). The behavior of chloropyridazine toward hydrazines, thiourea, sodium azide, anthranilic acid, aromatic amines and sulfa compounds have also been taken into consideration. Thethiopyridazinone derivativeswere prepared from the reaction of pyridazinone with phosphorus pentasulphide (P₂S₅). All the structures of were established on the based of spectroscopic data.