Reaction of (chloro carbonyl) phenyl ketene with 5-amino pyrazolones: Synthesis, characterization and theoretical studies of 7-hydroxy-6-phenyl-3-(phenyldiazenyl)pyrazolo[1,5-a]pyrimidine-2,5(1H,4H)-dione derivatives

•Highly efficient synthesis of pyrazolopyrimidines.•Easy product separation and purification.•Excellent yields and short reaction time.

New 7-hydroxy-6-phenyl-3-(phenyldiazenyl)pyrazolo[1,5-a]pyrimidine-2,5(1H,4H)-dione derivatives were synthesized from the reaction of (chlorocarbonyl)phenyl ketene and 5-amino pyrazolones in high to excellent yields and short reaction times. Structures of the new compounds were fully characterized by their spectral data IR, 1H NMR, and 13C NMR and by the theoretical results. Density Functional Theory (DFT) was used to optimize the structures, compute the energies and vibrational frequencies IR and 1H NMR shielding tensors of the desired products. The theoretical results excellent are compared with the experimental data.

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