Polyaniline/SiO2 Catalyzed One-pot Synthesis of Tetrahydrobenzo[b]pyran Derivatives

Polyaniline/SiO2 is an efficient catalyst for the synthesis of tetrahydrobenzo[b]pyran derivatives from a one-pot, three component, condensation of aldehydes, malononitrile and dimedone at room temperature. This protocol has several advantages such as high yield, a simple work up procedure, low toxicity and easy recovery and reusability of the catalytic material. The catalyst has been readily prepared and characterized by means of thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR).Keywords: Chemical Oxidative Method, Polyaniline/SiO2, Tetrahydrobenzo[b]pyra

SnO2/SiO2 Nanocomposite Catalyzed One-pot, Four-component Synthesis of 2-Amino-3-Cyanopyridines

An efficient and rapid protocol for the synthesis of 2-amino-3-cyanopyridines by the cyclocondensation reaction of aromatic aldehydes, methyl ketones, malononitrile and ammonium acetate catalyzed by SnO2/SiO2 nanocomposite material at refluxed condition in ethanol was investigated. Nanocomposite (SnO2/SiO2) catalytic material has been synthesized by using the sol-gel method. The prepared catalytic materials were characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT–IR), Brunauer-Emmer-Teller (BET) surface area, and temperature-programmed desorption of ammonia (NH3-TPD). Advantages of the present method include a simple work-up procedure, high yields of the products, low toxicity and easy recovery and reusability of the catalytic materials.Keywords: SnO2/SiO2, sol-gel, nanocomposite, 2-amino-3-cyanopyridines, heterogeneous catalys