A green one-pot three-component synthesis of tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives using a Fe₃O₄@SiO₂–imid–PMAⁿ magnetic nanocatalyst under ultrasonic irradiation or reflux conditions

Abstract

A green one----pot three----component synthesis of tetrahydrobenzo [b]pyran and 3,4----dihydropyrano[c]chromene derivatives using Fe 3 O 4 @SiO 2 -imid-PMA n magnetic nanocatalystunder ultrasonic irradiationor reflux conditions Abstract An efficient and environmentally benign procedure for the synthesis of tetrahydrobenzo [b]pyran and 3,4-dihydropyrano[c]chromene derivatives has been developed by one-pot three-component reaction of various aldehydes, malononitrile, and dimedoneor hydroxycoumarinin the presence of Fe 3 O 4 @SiO 2 -imid-PMA n nanoparticles as magnetic catalysts under ultrasonic irradiation or reflux conditions in water.This new procedure has the notable advantages such as operational simplicity, excellent yields, short reaction time, and absence of any tedious workup or purification. In addition, the excellent catalytic performance in water medium and the easy preparation, thermal stability and separation of the catalyst make it a good heterogeneous system and a useful alternative to other heterogeneous catalysts. Also, the catalyst can be easily recovered by a magnetic field and reused for eight consecutive reaction cycles without significant loss of activity.

Green, cost‐effective and efficient procedure for Heck and Sonogashira coupling reactions using palladium nanoparticles supported on functionalized Fe3O4@SiO2 by polyvinyl alcohol as a highly active, durable and reusable catalyst

“…In continuation of our interest in designing environmentally benign chemical processes, after fully characterizing the prepared catalyst, Fe 3 O 4 @SiO 2 –TCT–PVA–Pd(0), we report the ability of Fe 3 O 4 @SiO 2 –TCT–PVA–Pd(0) as a highly active and durable magnetically separable catalyst in the Heck and Sonogashira reactions.…”

Fast Efficient and General PASE Approach to Medicinally Relevant 4H,5H‐Pyrano‐[4,3‐b]pyran‐5‐one and 4,6‐Dihydro‐5H‐pyrano‐[3,2‐c]pyridine‐5‐one Scaffolds

“…M.p. 261 – 263 °C (: 260 – 261 °C). 1 H‐NMR (300 MHz, (D 6 )DMSO): 4.45 ( s , CH); 7.21 – 7.51 ( m , 7 arom.…”

“…M.p. 258 – 260 °C (: 255 – 256 °C). 1 H‐NMR (300 MHz, (D 6 )DMSO): 4.62 ( s , CH); 6.27 – 6.28 ( m , 1 H of fur); 6.36 – 6.38 ( m , 1 H of fur); 7.45 – 7.52 ( m , 2 arom.…”

One-pot synthesis of multisubstituted imidazoles catalyzed by Dendrimer-PWAn nanoparticles under solvent-free conditions and ultrasonic irradiation

“…Although these materials are versatile compounds in their acidic form, their main disadvantages are high solubility in polar solvents and low surface area (\10 m 2 /g). Therefore, in a homogeneous reaction, the isolation of the products and the reuse of the catalyst after reaction become difficult [30][31][32][33]. Therefore, in order to overcome this problem, these materials are dispersed on supports (such as silica, acidic ionexchange resins, active carbon, etc.)…”