Synthesis of β-Lactams from Acids and Imines Using Thiocarbonyldiimidazole

Thiocarbonyldiimidazole has been found to be an efficient acid activator for the synthesis of β-lactams by ketene-imine cycloaddition at room temperature. The experimental procedure is simple and results in excellent yields of the products. All products were characterized by spectral data and elemental analyses.     

Room Temperature Catalytic Aromatization of Hantzsch 1,4-Dihydropyridines by Sodium Nitrite in the Presence of Acidic Silica Gel

Summary. Various alkyl, aryl, and heterocyclic Hantzsch 1,4-dihydropyridines were converted to the corresponding pyridines in excellent yields and short times using sodium nitrite in the presence of a catalytic amount of acidic silica gel at room temperature.     

One-pot synthesis of tri- and tetra-substituted imidazoles using sodium dihydrogen phosphate under solvent-free conditions

<正>Sodium dihydrogen phosphate(NaH_2PO_4) efficiently catalyzes the condensation reaction of benzil,aldehydes,amines and ammonium acetate in a four-component reaction under solvent-free conditions.The reaction proceeds rapidly and affords the corresponding tetra-substituted imidazoles in high yields.Also an efficient route was developed for the synthesis of tri-substituted imidazoles from condensation of benzil,aldehydes and ammonium acetate using NaH_2PO_4.     

Efficient one-pot synthesis of 14-substituted-14H-dibenzo[a,j]xanthenes using boric acid under solvent-free conditions

<正>Boric acid efficiently catalysed the one-pot reaction of alkyl or aryl aldehydes with 2-naphthol to afford the corresponding 14- alkyl-or aryl-14H-dibenzo[a,j]xanthenes in good yields under solvent-free conditions.     

One step synthesis of 14-alkyl- or aryl-14H-dibenzo[a,j]xanthenes using sodium hydrogen sulfate as catalyst

A simple and environmentally benign procedure for the synthesis of 14-alkyl- or aryl-14H-dibenzo[a,j]xanthenes is described through a one-pot condensation of 2-naphthol with aryl or alkyl aldehydes in the presence of sodium hydrogen sulfate as a catalyst under solvent-free conditions.     

Nano-copper chromite (nano-CuCr2O4): a novel and efficient catalyst for the synthesis of biscoumarin and pyrano[c]chromene derivatives in water at room temperature

Research on Chemical Intermediates - A clean, efficient and eco-friendly procedure has been developed using nano-copper chromite (nano-CuCr2O4) as catalyst for the synthesis of biscoumarin and...     

Oxidation of Benzylic Methylene Compounds to Ketones with 4-Aminoperoxybenzoic Acid Supported on Silica Gel in Presence of Oxygen or Air

Summary. 4-Aminoperoxybenzoic acid supported on silica gel in presence of oxygen or air was found to be a convenient and selective oxidant for the oxidation of benzylic methylene compounds to the corresponding ketones.     

Tris(hydrogensulfato) boron as a solid heterogeneous catalyst for the rapid synthesis of α,α’-benzylidene bis(4-hydroxycoumarin) derivatives

α, α’-Benzylidene bis（4-hydroxycoumarin） derivatives were readily prepared in a few minutes with good yields through the reaction of an aromatic aldehyde and 4-hydroxycoumarin in aqueous media in the presence of catalytic tris（hydrogensulfato） boron [B（HSO₄）₃].