Heteropoly acids-catalyzed organic reactions in water: doubly green reactions

Abstract

The organic reactions in water, as the most significant green solvent, have attracted much attention due to their unique properties over conventional organic ones. In the catalytic area, heteropoly acids (HPAs) are also promising green solid acids to replace environmentally harmful liquid acid catalysts. Herein, we wish to report the organic reactions catalyzed by HPAs, their salt, and polyoxometalates (POMs) in aqueous systems.

Isocyanide-based multicomponent reactions in the synthesis of heterocycles

“…We also are kin to update the applications of name reactions in the total synthesis of natural products [118][119][120][121][122][123][124][125][126][127][128] and applications of different synthons, reagents and catalysts in organic synthesis [129][130][131][132][133][134][135] .…”

H5BW12O40as a green and efficient homogeneous but recyclable catalyst in the synthesis of 4H‐Pyransviamulticomponent reaction

“…We have already found out that HPAs have both advantages in addition of being green and acting efficiently in water as the greenest solvent and since organic compounds are rarely soluble in water due to their inherent lipophilicity [40a, 45]. In the last decade, we established HPAs as efficient heterogeneous and homogeneous catalysts, which were both were easily separated from the reaction mixture.…”

Amelioration of H4[W12SiO40] by nanomagnetic heterogenization: For the synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives

“…A mechanism of the synthesis of 1 H –pyrazolo[1,2‐ b ]phthalazinedione derivatives catalysed by the STA‐Amine‐Si‐Magnetite nanoparticles is proposed, as shown in Scheme . Heteropoly acids play a role similar to that of Brønsted acids in catalysis . Initially, STA protonates the carbonyl group of the aldehyde which further undergoes Knoevenagel condensation with malanonitrile.…”