Preparation and characterization of an eco-friendly ZnFe2O4@alginic acid nanocomposite catalyst and its application in the synthesis of 2-amino-3-cyano-4H-pyran derivatives

摘要

Alginic acid as a linear polysaccharide derived from natural resources can be used in the role of a green catalyst in organic reactions. Properties such as reactivity, renewability and biodegradability make this polysaccharide as an eco-friendly organocatalyst. In the synthesis of organic compounds, the development of effective methods for the synthesis of 4H-pyran compounds is important because of its extensive medicinal and biological activities. In this study, ZnFe5O4@alginic acid nanocomposite was synthesized by a simple procedure. Then, it was utilized as a green, cost-effective and heterogeneous catalyst in the synthesis of 2-amino-3-cyano-4H-pyran derivatives with a one-pot three-component reaction between various aromatic aldehydes, dimedone and malononitrile. Conventional methods such as Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) image, energy-dispersive X-ray (EDX) analysis, vibrating sample magnetometer (VSM) curve and inductively-coupled plasma atomic emission spectroscopy (ICP-AES) analysis were employed to characterize the prepared nanocomposite. This protocol offers some beneficial features such as green catalyst, mild reaction conditions, simple procedure, easy workup, short reaction times and significant yield of the products. The magnetic properties of the nanocomposite caused its easy separation by using an external magnetic field from the reaction mixture without significant loss of its catalytic activity. (C) 2019 Elsevier Ltd. All rights reserved.