The ability of SnCl2.2H2O as catalyst to promote the Biginelli three-component condensation reaction from a diversity of aromatic aldehydes, ethyl acetoacetate and urea or thiourea is described. The reaction was carried out in acetonitrile or ethanol as solvents in neutral media and represents an improvement of the classical Biginelli protocol and an advantage in comparison with FeCl3.6H2O, NiCl2.6H2O and CoCl2.6H2O which were used with HCl as co-catalyst. The synthesis of 3,4-dihydropyrimidinones was achieved in good to excelent yields.

An In–SiO₂ composite was prepared by the sol–gel method and was applied as a heterogeneous Lewis acid catalyst in the multicomponent Hantzsch synthesis of symmetrical and non-symmetrical 1,4-DHPs. The Ca²⁺ channel blockers nifedipine and nemadipine B were synthesized in a single step through a solvent-free protocol.

A series of new hybrid fluorescent Biginelli compounds, including a Monastrol derivative, were designed and synthesized with good yields. The photophysical studies revealed dual fluorescence emission, attributed to excited enol forms (E*) and tautomeric (K*) species, respectively, due to the ESIPT mechanism. The cytotoxic activity of all compounds was evaluated against MCF-7, Caco-2 and PC3 cancer cell lines and PNT2 normal prostate cells. The fluorescent Monastrol derivative 8f was the most active with cytotoxic activity very similar to cisplatin, whereas derivative 8c was the most selective towards the PC3 prostate cancer cells. The confocal laser scanning microscopy images of PC3 and MCF-7 cancer cell lines were acquired after incubation of the fluorescent Biginelli hybrids 8c and 8f, respectively, demonstrating efficient cellular uptake of both compounds and strong fluorescence within the intracellular medium. These results show that the new hybrid 3,4-dihydropyrimidin-2-(thi)ones are dual-function bioactive compounds that act both as fluorescent probes and antineoplastic agents.

A series of nine metal chloride hydrates (ZnCl2.2H2O, SnCl2.2H2O, CdCl2.2H2O, MnCl2.4H2O, CoCl2.6H2O, SrCl2.6H2O, NiCl2.6H2O, CrCl3.6H2O and CeCl3.7H2O) was investigated as mild and inexpensive Lewis acid catalysts to promote the multicomponent synthesis of triarylimidazoles. Reactions starting from benzil showed the best results when SnCl2.2H2O was used, while for benzoin as the starting material, CeCl3.7H2O was more efficient. All reactions were performed in EtOH as solvent. These catalysts were also successfully employed in the synthesis of triaryloxazoles.