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The present review surveys the broad chemical aspects of azines, since they have not previously been done in any detail.

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Fe3O4 nanoparticles were prepared by chemical coprecipitation method. Subsequently immobilization of chitosan on Fe3O4 nanoparticles was accomplished and afforded magnetic Fe3O4-chitosan nanoparticles. Synthesized nanoparticles was found to be a magnetic and heterogeneous catalyst for a one-pot and efficient synthesis of 2-amino-4H-chromenes by condensation of aldehydes with malononitrile and resorcinol under ultrasound irradiation as an ecofriendly method. This convenient procedure allowed us to achieve products under ultrasound irradiation in short time and excellent yield without using of harmful catalyst. The present method will permit a further increase of the diversity within the 2-amino-4H-chromene family.

Chitosan-coated Fe3O4 nanoparticles (Fe3O4@CS) were prepared simply through in situ co-precipitation of Fe2+ and Fe3+ ions via NH4OH in an aqueous solution of chitosan and their catalytic activity was investigated in the synthesis of 2,4,5-trisubstituted imidazoles by a one-pot condensation of benzil derivatives, aryl aldehydes and ammonium acetate in EtOH.

Brønsted acidic ionic liquid based magnetic nanoparticles: a new promoter for the Biginelli synthesis of 3,4-dihydropyrimidin-2(1H)ones/thiones Javad Safari* and Zohre ZarnegarThe Brønsted acidic ionic liquid 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium hydrogen sulfate was immobilized on magnetic Fe 3 O 4 nanoparticles (MNPs-IL-HSO 4 ). The properties of the magnetic nanocatalyst were characterized by FT-IR, EDX, SEM, elemental analysis, XRD, VSM, and TGA. The results showed that the ionic liquid had been successfully immobilized onto the magnetic support, and the immobilized ionic liquid catalysts exhibited high catalytic activity in the Biginelli reaction under mild conditions for the synthesis of a diverse range of 3,4-dihydropyrimidin-2(1H)-ones. It also maintained satisfactory catalytic activity for the synthesis of Biginelli compounds after 8 rounds of recycling. The separation and reuse of the novel solid catalyst were simple, effective and economical.

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