Ultrasonic assisted synergetic green synthesis of polycyclic imidazo(thiazolo)pyrimidines by using Fe3O4@clay core-shell

Abstract

A practical and green approach for the ultrasound-enhanced one-pot multicomponent synthesis of tetraheterocyclic imidazo(thiazolo)pyrimidines is described via the condensation of an 2-aminobenzimidazole or 2-aminobenzothiazole, dimedone and various aldehydes in the presence of FeO@clay as an environmentally benign and reusable core/shell nanocomposite catalyst in relatively quantitative yields. This novel eco-friendly protocol includes several advantages such as avoiding hazardous solvents, reusability of the catalyst, easy work-up, short reaction times, room temperature and mild reaction conditions. Furthermore, ultrasonic irradiation and synergistic catalyst showed considerable superiority vs. traditional heating or stirring conditions.

Sonochemical rate enhanced by a new nanomagnetic embedded core/shell nanoparticles and catalytic performance in the multicomponent synthesis of pyridoimidazoisoquinolines

“…At first, heterogeneous magnetic nanocatalyst was readily prepared according to the previous literature procedures [19][20][21][22][23][24][25] by preparation of Fe 3 O 4 @SiO 2 and then its functionalization by 4aminobenzoyl chloride. The particle size was studied by scanning electron microscopy (SEM) and the identification of Fe 3 O 4 @SiO 2 -CO-C 6 H 4 -NH 2 was based on the analysis of SEM images that clearly showed a monodispersed spherical shape of the nanoparticles with average particle size distribution of about 65 nm ( Fig.…”

“…In a typical procedure for the synthesis of Fe 3 O 4 @SiO 2 -CO-C 6 H 4 -NH 2 nanocatalyst, first, 2.0 g of as-prepared Fe 3 O 4 @SiO 2 nanoparticles [19][20][21][22][23][24][25] were dispersed in 10 mL of dry toluene in an ultrasonic water bath. Then, 2 mL of 4-aminobenzoyl chloride was added and mixture was sonicated for 3 ⁄ 30 min with a frequency of 40 kHz at 250 W. After that, the solid materials were separated by an external magnet and washed with hot EtOH.…”

“…In connection with our interest in design and development of magnetic nanocatalysts and multicomponent reactions [18][19][20][21][22][23][24][25], herein, we wish to report the sonochemical synthesis of pyrido[2 0 ,1 0 :2,3]imidazo[4,5-c]isoquinolines 4a-j via a one-pot three-component reaction of o-phthalaldehyde 1, TMSCN 2 and 2-aminopyridines 3 in the presence of a catalytic amount of modified magnetic iron oxide nanoparticles (Fe 3 O 4 @SiO 2 -CO-C 6 H 4 -NH 2 ).…”

Agar: a natural and environmentally-friendly support composed of copper oxide nanoparticles for the green synthesis of 1,2,3–triazoles

“…Metals-based nanoparticles have been widely used as a catalysts to perform various organic reactions, such as oxidation and reduction reactions, A 3 coupling, crosscoupling, tandem, multicomponent reactions, oxidative coupling, click and cycloaddition reactions because of their suitable properties to promote the reactions under green and sustainable procedure (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25).…”

Fabrication of weak‐acid functionalized mesoporous carbon solid acid from tannic acid and its use for saccharification of cellulose

“…Utilization of enzyme shows several problems such as high enzyme cost, slow process, and difficulty in enzyme recovery . Currently, solid acid catalysts show good prospects for hydrolysis of recalcitrance cellulose since it is friendly to environment, has high reaction rate even though the process was done in mild condition, reusable, can be recovered and separated from the products of saccharification .…”