Mesoporous molecular sieve MCM-41 catalyzed one-pot synthesis of 3,4-dihydro-2(1H)-pyrimidinones and –thiones under solvent-free conditions

An efficient synthesis of 3,4-dihydro-2(1H)-pyrimidinones and -thiones using MCM-41 as the catalyst from an aldehyde, β-keto ester, and urea or thiourea under solvent-free conditions is described.KEY WORDS: Biginelli reaction, Dihydropyrimidinones, MCM-41, One-pot, Reusable Bull. Chem. Soc. Ethiop. 2011, 25(2), 309-313

EFFICIENT SODIUM SELENATE-CATALYZED SYNTHESIS OF 3,4-DIHYDRO-2(1H)-PYRIMIDINONES AND –THIONES UNDER SOLVENT-FREE CONDITIONS

Sodium selenate efficiently catalyzes the three-component Biginelli reaction of an aldehyde, a,β-keto ester and urea or thiourea under solvent-free conditions to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones or –thiones in excellent yields. KEY WORDS: Dihydropyrimidinones, Sodium selenate, Biginelli reaction, Three component reaction Bull. Chem. Soc. Ethiop. 2009, 23(1), 141-144

A catalytic method for the synthesis of 4-alkyl(aryl)-6-aryl-3-cyano-2(1H)-pyridinones and their 2-imino isosteres as nonsteroidal cardiotonic agents

A highly efficient procedure for the synthesis of 4-alkyl(aryl)-6-aryl-3-cyano-2(1H)-pyridinones and their 2-imino isosteres via a one-pot multicomponent reaction of 3,4-dimethoxyacetophenone, malonitrile or ethyl cyanoacetate, an aldehyde and ammonium acetate in the presence of K2CO3 is achieved in good yields. KEY WORDS: 3-Cyano-2(1H)-pyridinones, 2-Imino, Cardiotonic, Dimethoxyacetophenone  Bull. Chem. Soc. Ethiop. 2010, 24(3), 433-438

DABCO as a novel and efficient catalyst for the synthesis of 4(3H)-quinazolinone derivatives

4(3H)-Quinazolinones were synthesized in high to excellent yields through the one-pot condensation of anthranilic acid, trimethyl orthoformate and primary amines in the presence of DABCO under solvent free conditions.KEY WORDS: 4(3H)-Quinazolinone, DABCO (1,4-diazabicyclo[2,2,2]octane), Trimethyl orthoformate, Anthranilic acid Bull. Chem. Soc. Ethiop. 2011, 25(2), 305-308

Synthesis of a novel heterocyclic system: Oxazolo[2,3-c][1,2,4]benzotriazine

585-58

The synthesis of 2-iminochromenes using mesoporous molecular sieve MCM-41 as a heterogeneous and recyclable catalyst

A highly efficient procedure for the synthesis of 2-iminochromenes via condensation of o-hydroxybenzaldehydes and malononitrile using a catalytic amount of mesoporous molecular sieve MCM-41 in good yields is achieved. KEY WORDS: 2-Iminochromenes, Recyclable catalyst, MCM-41, o-Hydroxybenzaldehydes  Bull. Chem. Soc. Ethiop. 2010, 24(2), 273-276

Superparamagnetic Iron Oxide as an Efficient Catalyst for the One-Pot, Solvent-Free Synthesis of 5,5-Disubstituted Hexahydropyrimidines and Their Spiro Analogues

Superparamagnetic Fe 3 O 4 is shown to act as a very efficient catalyst for the one-pot, three-component synthesis of 5,5-disubstituted hexahydropyrimidines and their spiropiperidines. e catalyst is easily recovered by the use of an external magnet and reused in several reactions without any noticeable loss of activity. e products are obtained in short time and good purity upon separation of the catalyst and evaporation of the volatiles of the reaction mixture

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

Microwave assisted synthesis of hydroxychromenes using imidazole-functionalized silica nanoparticles as a catalyst under solvent-free conditions

A microwave-assisted reaction of various salicylaldehydes with dialkyl acetylenedicarboxylates mediated by imidazole-functionalized silica nanoparticles is successfully and rapidly achieved to afford the corresponding hydroxychromenes in high to excellent yields under solvent-free conditions