Heteropolyacids in synthesis of benzoyl hydrazone derivatives

Keggin type of heteropolyacids as green reusable and efficient catalyst was used in the synthesis of benzoyl hydrazones from reaction of benzoic acid hydrazide and aldehyde and ketone derivatives. The synthesis of N-acetyl and N-benzoyl derivatives has also been performed by the reaction of obtained benzoyl hydrazones with acylcholorides in presence of this kind of heteropolyacids

Solvent-free synthesis of xanthene derivatives by Preyssler type heteropolyacid

Dimedone reacted with aromatic aldehydes and 3,4-methylenedioxyphenol or β-naphthol in the presence of a catalytic amount of Preyssler type heteropolyacid, H14[NaP5W30O110], as a green and reusable catalyst under solvent-free conditions to form a variety of  new xanthene derivatives in very good  yields.KEY WORDS: Xanthene derivatives, Solvent-free synthesis, Preyssler type heteropolyacid, 3,4-Methylene dioxyphenol, β-Naphthol, Three-component one-pot reactions Bull. Chem. Soc. Ethiop. 2011, 25(3), 399-406

One-Pot Synthesis of Tetrasubstituted Imidazoles Catalyzed by Preyssler-Type Heteropoly Acid

Abstract: A simple one-pot four-component synthetic method was reported for the preparation of tetrasubstituted imidazole derivatives from benzil, aromatic aldehydes, primary amines and ammonium acetate in the presence of Preyssler-type heteropoly acid catalyst. This method was proved to be ecobenign, easy work-up, convenient, relatively short reaction times and the products were isolated with high yields

Facile Immobilization of a Lewis Acid Polyoxometalate onto Layered Double Hydroxides for Highly Efficient N-Oxidation of Pyridine-Based Derivatives and Denitrogenation

N-Oxides are a class of highly important compounds which are widely used as synthetic intermediates. In this paper, we demonstrate for the first time the use of a polyoxometalate (POM) based composite material, as highly efficient heterogeneous catalyst for the N-oxidation of pyridines and its derivatives in the presence of H2O2 at room temperature. The composite was prepared by intercalation of the [La(PW11O39)2]11- anion into a tris(hydroxymethyl)aminomethane (Tris) modified layered double hydroxides (LDHs). Additionally, the Tris-LDH-La(PW11)2–based catalyst has been employed for the denitrogenation of a model oil mixture in the presence of [bmim]BF4 and H2O2. Deep denitrogenation can be achieved in 40 minutes at 75 °C. Finally, the heterogeneous catalyst can be easily recovered and reused at least ten times without measurable decrease of the catalytic activity and disintegration of the Tris-LDH-La(PW11)2 structure

Synthesis and Characterization of Two Novel Organic-Inorganic Compounds Based on Tetrahexyl and Tetraheptyl Ammonium Ions and the Preyssler Anion and Their Catalytic Activities in the Synthesis of 4-Aminopyrazolo[3,4-d]- Pyrimidines

Two novel organic–inorganic compounds based on tetrahexylammonium (THA) and tetraheptylammonium (THPA) ions and the Preyssler anion, [NaP5W30O110]14-, were synthesized and formulated as (THA)7.7H6.3 [NaP5W30O110] (A) and (THPA)7.5 H6.5[N aP5W30O110] (B). The synthesized compounds were characterized by IR, UV, and TGA and used for the catalytic synthesis of 4-aminopyrazolo[3,4,-d]pyrimidine derivatives 2a-2d. Our findings showed efficient catalytic activities for A and B