Synthesis and Spectral Characterisation of Some Phthalazinone Derivatives

1,2,4-Triazol-3-yl, 1,3,4-oxadiazol-2-yl, 1,3-dioxoisoindolin-2-yl, 1 H-pyrazol-4-yl, phthalazin-1(2 H)one, 5 H-2,3-benzodi-azepine-1,4-dione and pyridazine-1,4-dione derivatives were prepared via the reaction of the readily obtainable starting material 1-oxo-1,2-dihydrophthalazin-4-carbohydrazide with one carbon donor like phenyl isothiocyanate, phenyl isocyanate, triethylorthoformate, formic acid and different electrophilic reagents such as anhydrides, chromen-1,3-dione, chloroacetyl chloride, acetic anhydride, arylidene malononitrile, ethoxymethylene malononitrile and ethyl acetoacetate.