A mild protocol for the preparation of 2-amino- dihydropyrano[3,2-b] pyran-3-carbonitriles via cobalt nanoparticles-catalyzed multi-component reaction in water

An improved rapid one-pot and green synthesis of substituted pyranopyranes by condensing Kojic acid, malononitrile, and different aldehydes using a catalytic amount of cobalt nanoparticles as a green and reusable catalyst is reported for the first time. The reaction proceeds in aqueous media at ambient temperature. Furthermore, the structural and morphological study of the cobalt nanoparticles was carried out using scanning electron microscopy (SEM), energy dispersive X-ray spectrum (EDS), and Dynamic light scattering (DLS) techniques. Utilization of simple procedure, high yields and the ease of separation of pure product, ease of catalyst separation by an external magnet and convenient manipulation make this methodology an interesting option for green synthesis of 2-amino-dihydropyranopyran-3-carbonitriles.