A novel base-metal multifunctional catalyst for the synthesis of 2-amino-3-cyano-4H-chromenes by a multicomponent tandem oxidation process.

ABSTRACT: A novel base-metal multifunctional nanomagnetic catalyst is prepared by the immobilization of tungstate anions onto γ-Fe₂O₃ supported with imidazolium moieties. The (γ-Fe₂O₃-Im-Py)₂WO₄ was fully characterized using FT-IR, XPS, TEM, FESEM, ICP, TGA, VSM and XRD and used as a multifunctional heterogeneous catalyst for the synthesis of 2-amino-3-cyano-4H-chromenes via a multicomponent tandem oxidation process starting from alcohols under solvent-free conditions. During this process, tungstate catalyzes the oxidation of a wide range of alcohols in the presence of TBHP as a clean source. The in-situ formed aldehydes are condensed with malononitrile and β-dicarbonyl compounds/naphthols/4-hydroxycumarin through promotion by pyridine and imidazolium moieties of the catalyst. By this method, a variety of 2-amino-3-cyano-4H-chromenes are generated in good to high yields from alcohols as inexpensive and easily available starting materials. The catalyst is recovered easily by the aid of an external magnetic field and reused in five successive runs with insignificant decreasing activity.

SUBMITTER: Chahkamali FO 

PROVIDER: S-EPMC8861043 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature