Various Biginelli compounds (dihydropyrimidinones) have been synthesized efficiently and in high yields under mild, solvent-free, and eco-friendly conditions in a one-pot reaction of 1,3-dicarbonyl compounds, aldehydes, and urea/thiourea/acetyl thiourea using lithium-acetate as a novel catalyst without the addition of any proton source. Comparative catalytic efficiency of lithium-acetate and polyphosphoric acid to catalyze Biginelli condensation is also studied under neat conditions. The reaction is carried out in the absence of any solvent and represents an improvement of the classical Biginelli protocol and an advantage in comparison with FeCl3 ·6H2O, NiCl2 ·6H2O and CoCl2 ·6H2O that were used with HCl as a cocatalyst. Compared to classical Biginelli reaction conditions, the present method has advantages of good yields, short reaction times, and experimental simplicity. The obtained products have been identified by spectral (1H NMR and IR) data and their melting points. The prepared compounds are evaluated for anticancer activity against two human cancer cell lines (lung cancer cell line A549 and breast cancer cell line MCF7).

A simple catalytic protocol for the synthesis of novel spiro[indoline-pyranodioxine] derivatives has been developed using ZnO nanoparticle as an efficient, green, and reusable catalyst. The derivatives are obtained in moderate to excellent yield by one-pot three-component reaction of an isatin, malononitrile/ethylcyanoacetate, and 2,2-dimethyl-1,3-dioxane-4,6-dione in absolute ethanol under conventional heating and microwave irradiation. The catalyst was recovered by filtration from the reaction mixture and reused during five consecutive runs without any apparent loss of activity for the same reaction. The mild reaction conditions and recyclability of the catalyst make it environmentally benign synthetic procedure.

An efficient catalytic protocol for the synthesis of novel spiro[indoline-3,4′-pyrano[2,3-c]thiazole]carbonitriles and condensed thiazolo[5′′,4′′:5′,6′]pyrano[4′,3′:3,4]furo[2,3-b]indole derivatives is developed in a one-pot three-component approach involving substituted 1H-indole-2,3-diones, activated methylene reagent, and 2-thioxo-4-thiazolidinone under conventional heating and microwave irradiation. This paper describes the use of NiO nanoparticles as catalyst for the synthesis of novel spiro and condensed indole derivatives by Knoevenagel condensation followed by Michael addition. The advantageous features of this methodology are operational simplicity, high yield processing, and easy handling. The particle size of NiO nanoparticle was determined by XRD. After reaction course, NiO nanoparticles can be recycled and reused without any apparent loss of activity.

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