Abstract
ABSTRACTAn efficient multi-component synthesis of 10,10-dimethyl-7-(phenyl)-10,11-dihydrochromeno[4,3-b]chromene-6,8(7H,9H)-diones is described by a one-pot condensation reaction of aldehydes, dimedone and 4-hydroxycoumarin using L-phenyl alanine tethered to nano-Fe3O4@SiO2 under ultrasonic irradiation. The catalyst has been characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDX), thermal gravimetric analysis (TGA) and vibrating-sample magnetometer (VSM). Atom economy, wide range of products, high catalytic activity, excellent yields in short reaction times, reusability of the catalyst and low catalyst loading are some of the important features of this protocol.
Highlights
Ultrasound irradiation has been employed to accelerate a number of practicable reactions through the formation, growth, and implosive collapse of bubbles [1–3]
The synthesis of chromenes through multicomponent reactions (MCRs) has attracted much attention due to excellent synthetic efficiency, experimental simplicity, inherent atom economy and their ability to create molecular complexity starting from simple substrates [11, 12]
We report an efficient method for synthesize of L-phenyl alanine-supported Fe3O4@SiO2 core/shell MNPs as an efficient catalyst for the preparation of 10,10-dimethyl-7-(phenyl)-10,11dihydrochromeno[4,3-b]chromene-6,8(7H,9H )-diones by one-pot condensation of aldehydes, dimedone and 4hydroxy coumarin under ultrasonic irradiation (Scheme 1)
Summary
Ultrasound irradiation has been employed to accelerate a number of practicable reactions through the formation, growth, and implosive collapse of bubbles [1–3]. The development of facile, efficient, flexible and useful methods for the synthesis of chromenes is still favorable [10]. The synthesis of chromenes through multicomponent reactions (MCRs) has attracted much attention due to excellent synthetic efficiency, experimental simplicity, inherent atom economy and their ability to create molecular complexity starting from simple substrates [11, 12]. The core/shell Fe3O4 nanoparticles are prepared and have been widely studied due to their unique physical properties. The core/shell Fe3O4 nanoparticles can be recycled from the medium of reaction by external magnetic field [13, 14]. Therefor the modified magnetic nanoparticles with all these features are used for varied organic reactions under ultrasonic irradiations [25, 26]. The ultrasound approach offers several advantages such as higher yields, enhanced organic reaction rates, milder reaction conditions, and waste minimization compared with traditional methods and saving money and energy.
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