A novel one pot synthesis of pyrazolo[4',3':5,6]pyrido[2,3-d]pyrimidine-diones, via a five-component reaction, involving, hydrazine hydrate, ethyl acetoacetate, and 1,3-dimethyl barbituric acid, an appropriate aryl aldehydes and ammonium acetate catalyzed via both of heterogeneous and homogeneous catalysis in water, is reported.

The title compound, C(21)H(26)N(2)O(5), was unexpectedly obtained as a by-product in the reaction of ethyl acetoacetate, 4-acetamido-benzaldehyde and urea under microwave irradiation. The dihydro-pyridine ring assumes a flattened boat conformation. Inter-molecular N-H⋯O and weak C-H⋯O hydrogen bonding occurs in the crystal.

The title compound, C(10)H(9)F(3)N(2)O(2), was prepared by the reaction of m-phenyl-enediamine and ethyl 4,4,4-trifluoro-acetoacetate. In the crystal, inter-molecular C-H⋯ F, N-H⋯F, O-H⋯N and N-H⋯O inter-actions contribute to the crystal packing.

An efficient and expeditious catalyst-free procedure was developed for the one- pot synthesis of 1, 4-dihydropyridine derivatives via the three-component reaction of various aldehydes, ethyl acetoacetate, and ammonium acetate in PEG-400. The reaction was carried out at 110°С and the products were obtained in good to high yields.

The one-pot, multi-component synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols) by tandem Knoevenagel-Michael reaction of phenylhydrazine, ethyl acetoacetate and aldehydes in the presence of silica-bonded N-propylpiperazine sulfamic acid (SBPPSA) as a recyclable solid acid catalyst was reported. SBPPSA showed much the same efficiency when used in consecutive reaction runs.

An efficient and expeditious catalyst-free procedure was developed for the one- pot synthesis of 1, 4-dihydropyridine derivatives via the three-component reaction of various aldehydes, ethyl acetoacetate, and ammonium acetate in PEG-400. The reaction was carried out at 110°С and the products were obtained in good to high yields.