the silica boron sulfuric acid nanoparticles (sbsans) as an efficient heterogeneous solid acid catalyst with both brønsted and lewis acidic sites catalyzed the preparation of bis-4-hydroxycoumarin derivatives using reaction of aldehydes and 4-hydroxycoumarin under mild and solvent-free condition at room temperature. this new and efficient methodology has advantages in comparison with currently ...

this study introduces a green and efficient method for preparation of biologically-active substituted 4h-pyrans using the one-pot three-component reaction of aromatic aldehydes, dimedone and malononitrile in the presence of cobalt oxide nanoparticles. co3o4 nanoparticles were used as an efficient catalyst for the synthesis of polyhydroquinoline derivatives by the reaction of aromatic aldehydes,...

nano sio2/hyperbranched polyglycerol (hpg)/so3h catalyst was readily prepared for first time from inexpensive starting materials in aqueous media which catalyzed the synthesis of benzoic acid. ftir spectra, x-ray diffraction (xrd) and transmission electron micrographs (tem) was employed to characterize the properties of the synthesized nano sio2/hpg/so3h. high catalytic activity and ease of rec...

microwave assisted green synthesis of α, ά- bis (substituted- benzylidene) alkanones by the crossed- aldol condensation reaction of substituted aryl aldehydes with ketones in the presence of catalytic amount of nbcl5 in good to excellent yields. this reaction is carried out under solvent-free conditions. the results showed that aldehydes bearing electron–donating substituent's on phenyl-ring fa...

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...