Immobilized TiO₂nanoparticles on carbon nanotubes: an efficient heterogeneous catalyst for the synthesis of chromeno[b]pyridine derivatives under ultrasonic irradiation

Abstract

A new synthesis of chromeno[b]pyridines is described via reaction of 4-aminocoumarin, aromatic aldehydes and malononitrile catalyzed by TiO2 nanoparticles immobilized on CNTs as an efficient heterogeneous catalyst under ultrasonic irradiation.

Ultrasound irradiation in heterocycle synthesis: An overview

“…A green three‐component protocol for the synthesis of chromeno[ b ]pyridine derivatives were developed by Abdolmohammadi et al [33] The reaction of malononitrile, benzaldehyde, and 4‐aminocoumarin under the optimized condition of 0.02 g TiO 2 –CNTs catalyst in water gave the expected product in 20 min at RT by sonication. The range of aryl aldehydes used to explore the generality of the reaction revealed that electron‐rich, electron‐deficient as well as heteroaryl aldehydes reacted well ensuing the desired product in excellent yield (Scheme 15).…”

A decennary update on applications of metal nanoparticles (MNPs) in the synthesis of nitrogen- and oxygen-containing heterocyclic scaffolds

“…TiO 2 NPs immobilized on CNTs (TiO 2 -CNTs) catalyzed Knoevenagel-Michael-cyclization for the green synthesis of chromeno[b]pyridines (331) using 4-amino coumarin (194b), aryl aldehyde (2) and malononitrile (29a) mediated by ultrasonic irradiation (Scheme 227). 403 The TiO 2 -NCTs were synthesized via the sonochemical treatment of multi-walled CNTs with tetraethyl orthotitanate using SDS as a stabilizer. The NC was separated by centrifugation and recycled for up to four runs with excellent activity in 94%, 93%, 93% and 92% yield for the model reaction between 194b, benzaldehyde and 29a.…”

Six-component synthesis and biological activity of novel spiropyridoindolepyrrolidine derivatives: A combined experimental and theoretical investigation

“…Also, these catalysts are employed in technology and applied science ( Sahay et al, 2012 ; Yang et al, 2019 ; Zhao et al, 2019 ; Chen et al, 2020 ; Yang et al, 2020 ). MWCNTs, owing to large surface area and high adsorption capability, have been extensively investigated (Zhang, et al, 2013; Khalilian et al, 2017 ; Samani et al, 2018 ; Abdolmohammadi, 2018 ; Abdolmohammadi et al, 2019 ; Abdolmohammadi et al, 2020b ). In the recent past, the supported catalyst and bimetallic oxide or trimetallic oxide catalysts were significant due to their high potentials in carrying out highly selective and efficient organic reactions ( Guo et al, 2004 ; Wachs, 2005 ; Dastan et al, 2012 ; Rabiei, et al, 2017 ; Fakheri-Vayeghan, et al, 2018 ; Janitabar-Darzi and Abdolmohammadi, 2019 ; Chaghari-Farahani, et al, 2020 ; Abdolmohammadi, et al, 2022 ; Zare Davijani et al, 2022a ).…”

“…For this reason, the mixture of two or more metals and their curing procedures permit the change of the properties of materials’ surface and optimization of the properties for a particular goal ( Zhang et al, 2012 ; Lin-Bing et al, 2015 ). Therefore, the mixture of metal oxide catalysts and nanocomposite structures of them exhibited production of heterocyclic compounds according to green rules with high efficiency ( Abdolmohammadi, et al, 2019 ; Abdolmohammadi et al, 2020a ; Kalantari et al, 2020 ; Abdolmohammadi, et al, 2021 ; Khalilzadeh et al, 2021 ). Among the metal oxide nanoparticles, Fe 3 O 4 magnetic nanoparticles (MNPs) are important because of high surface area, simple removing from reaction, and employment of it in MCRs several times.…”