Potassium hydrogen sulfate: An efficient catalyst in organic reactions

Potassium hydrogen sulfate, KHSO4, has been used in many organic preparations as a good solid catalyst. The KHSO4 has received considerable attention since it is an inexpensive, eco-friendly, highly reactive, easy to handle and non-toxic catalyst for various organic transformations, affording the corresponding products in excellent yields with high selectivity. We wish to report some applications of this catalyst in organic reactions

A new approach to the facile synthesis of 1,8-dioxooctahydroxanthene using nano-TiO2/ CNT as an efficient catalyst

1,8-dioxooctahydroxanthene derivatives have received considerable attention due to their valuable biological and medicinal properties such as anticoagulant, antispasmodic, diuretic, and anti-cancer activities. 1,8-dioxooctahydroxanthene derivatives have strong relaxing activity on blood vessels, cardiac muscles, and smooth muscles. The present study reports the easy synthesis of 1,8-dioxooctahydroxanthene derivatives using aldehydes and dimedon in the presence of nano-TiO2/ CNT as an efficient catalyst

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

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

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 an efficient catalyst for the synthesis of 3-cyano-2(1H)-pyridinones and their 2-imino analogues

3-cyano-2(1H)-pyridinones and their 2-imino analogues have been synthesized in good yields via a one-pot multi-component reaction of 3,4-dimethoxyacetophenone, malononitrile or ethylcyanoacetate, ammonium acetate and various aldehydes in the presence of  1,4-diaza-bicyclo[2,2,2]octane (DABCO) in ethanol. DABCO has been widely used as a catalyst for the organic reactions and we selected it as an efficient catalyst to synthesis of 3-cyano-pyridines. All products were characterized by melting point, IR, 1H NMR and GC/MS studies

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

<b>Efficient sodium selenate-catalyzed synthesis of 3,4-dihydro-2(1<i>H</i>)-pyrimidinones and –thiones under solvent-free conditions</b>

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(1<i>H</i>)-ones or –thiones in excellent yields

Heteropolyacids as an efficient and reusable catalytic system for the regiospecific nitration of phenols with metal nitrates

Highly regiospecific mononitration of phenols and substituted phenols is accomplished employing a metal nitrate and a catalytic amount of heteropolyacid in acetonitrile. An exclusive ortho-selectivity was observed with excellent yields. A variety of metal nitrates were used to obtain o-nitrophenols exclusively in good to excellent yields. The use of heteropolyacid is key for the selectivity observed.DOI: http://dx.doi.org/10.4314/bcse.v26i1.1