Synthesis, FT-IR Spectra and DFT calculations of indazolo phthalazinetrione derivatives

Heterocyclic chemistry is one of the most important fields in organic chemistry. Heterocycles containing the phthalazine ring are main object in synthetic and medicinal chemistry because they have many biologically actives. Multicomponent reactions of dimedone, an aldehyde, and N-nucleophilic heterocycles have recently attracted interest as different condensation products can be obtained depending on the specific conditions and structure of the building blocks.We reported an efficient method for the synthesis of indazolo phthalazinetrione derivatives by a fourcomponent condensation reaction of dimedone, aromatic aldehydes and hydrazine monohydrate and 3-nitrophthalic anhydride in the presence of a catalytic amount of Zr(NO3)2. 2H2O in ethanol in conditions of reflux. Sterically congested 2,2-disubstituted indane-1,3-dione derivatives have been synthesized and characterized by 1HNMR, 13CNMR and FT-IR and elemental analysis. The B3LYP/HF calculations for computation of FT-IR spectra have been carried out for the title compounds. Predicted vibrational frequencies have been assigned and compared with experimental FT-IR spectra and they are supported each other.