the chemistry of 2-oxo-1,2,3,4-tetrahydropyrimidines began to develop toward the end of 1893 year, when the first representatives of this class compounds were reported by p. biginelli. despite prior reports of several really effective catalytic and non-catalytic approaches towards biginelli-type products, an overwhelming number of new catalysts for the biginelli reaction have been recently publ...

an efficient method for the friedel–crafts acylation of a wide range of aromatic compounds in good to excellent yields under solvent-free conditions, using iron zirconium phosphate (zpfe) was investigated. the catalyst is easy to prepare and shows interesting catalytic properties. the catalyst was characterized by some instrumental techniques such as xrd, icp-oes, sem and tem. a wide variety of...

p2o5-sio2 (30% w/w) was found to be a useful catalyst for the synthesis of various 2-substituted aryl benzimidazoles under solvent-less and in solvent conditions from o-phenylenediamine and aldehydes. the products were directly recrystallized from methanol.

the esterification of free fatty acids (ffa) with methanol is studied using sulfonated porous carbon (spc) as catalyst. in compare to the amorphous sugar catalyst and protonated nafion, the proposed catalyst shows stability and high efficient performance in biodiesel production. the highest initial rate of oleic acid conversion is obtained at catalyst loading of 1 mmol h+ and mole ratio of meoh...

a green and efficient one pot, three component protocol for synthesis of naphthopyranopyrimidines by cyclocondensation of β-naphthol, aldehyde, and 6-amino-1,3-dimethyluracil using l-proline as a beneficial catalyst with high catalytic activity under solvent-free conditions at 100 °c is described. in this study, several types of aromatic aldehyde, containing electron-withdrawing groups as well ...

cobalt hydrogensulfate is an efficient catalyst for the condensation of β-naphthol, aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione at 120 °c to afford 9,9-dimethyl-12-phenyl-8,10,11,12-tetrahydro-9-h-benzo[a]xanthen-11-one derivatives in high yields. also, polycondensation reactions of phenols with phthalic anhydride were carried out in the presence of cobalt hydrogensulphate under so...

a simple, clean, and environmentally benign three-component process for the synthesis of 2-amino-4hchromenes using [mim]cl, as an efficient catalyst under solvent-free conditions are described. a wide range of aromatic aldehydes easily undergoes condensations with 1-naphthol and malononitrile under solvent-free conditions to afford the desired products of good purity in excellent yields. taking...

bifunctional acidic ionic liquids, having both h-imidazolium and -so3h groups as cation moieties (h-bfails) and cf3so3- as anion, were synthesized in high yields. these h-bfails showed significant hydrophilic properties, lower acidity and higher thermal stability relative to common ionic liquids, due to their unique structures. the (propyl or butyl-3-sulfonic) imidazolium trifluoromethane sulfo...

an efficient, simple and convenient route is described for the synthesis of biscoumarin (3,3'-(arylmethylene) bis (4-hydroxy-2h-chromen-2-one)) by using of recyclable catalyst tio2@ksf. in this method, we synthesis biscoumarin derivatives via 3multi-component reactions (3mcrs) of two equivalent 4-hydroxycoumarin with one equivalent of aromatic aldehydes using 20 mg nano tio2@ksf as homogen...