a simple highly versatile and efficient sonochemical synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles is achieved by condensation of 1,2-dicarbonyl compound, aldehyde, ammonium acetate and primary amine using antimony trichloride immobilized on silica gel (sio2-osbcl2) as a catalyst in ethanol at moderate temperature. operational simplicity, practicability and applicabi...

β-acetamido ketones were synthesized in excellent yields through one-pot condensation reaction of aldehydes, acetophenones, acetyl chloride, and acetonitrile in the presence of boric acid as a solid heterogeneous catalyst at room temperature. It is the first successful report of boric acid that has been used as solid acid catalyst for the preparation of β-acetamido ketones. The remarkable advan...

Cross-linked sulfonated polyacrylamide (Cross-PAA-SO3H) attached to nano-Fe3O4 as an efficientheterogeneous solid acid catalyst has been used for the preparation of spiro[pyrazoloquinoline-oxindoles]and spiro[chromenopyrazolo-oxindoles] through a four-component reactions of phenylhydrazineor hydrazine hydrate, isatins, ketoesters and naphthylamine or 2-naphthol under reflux co...

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 ...

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 ...

Due to the high price of virgin vegetable oils and the drawbacks of the homogeneous catalytic transesterification, in this work an economically profitable alternative process was proposed for biodiesel synthesis in which transesterification of the low-cost waste cooking oil (WCO) with methanol in a heterogeneous system was done. Alumina impregnated with sodium hydroxide was utilized as a solid ...

Neat chlorosulfonic acid reacts with anhydrous sodium tungstate to give tungstate sulfuric acid (TSA), a new dibasic inorganic solid acid in which two sulfuric acid molecules connect to a tungstate moiety via a covalent bond. A variety of oximes were oxidized to their parent carbonyl compounds under mild conditions with excellent yields in short times by a heterogeneous wet TSA/KMnO4 in dichlor...

Due to the high price of virgin vegetable oils and the drawbacks of the homogeneous catalytic transesterification, in this work an economically profitable alternative process was proposed for biodiesel synthesis in which transesterification of the low-cost waste cooking oil (WCO) with methanol in a heterogeneous system was done. Alumina impregnated with sodium hydroxide was utilized as a solid ...

silica-bonded n-propyltriethylene-tetramine (sbnptt) was found as an efficient solid base for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4h-chromenes. chromene derivatives were obtained via the three-component condensation reaction of aromatic aldehydes, malononitrile, and dimedone at 80 oc under solvent-free conditions. the heterogeneous solid base showed much the same efficiency when u...