1,3-Dibromo-5,5-dimethylhydantoin (DBH), as a cheap and commercially available reagent, is efficiently able to catalyze the synthesis of polyhydroquinoline derivatives and 12-aryl-8,9,10,12-tetrahydro[a] xanthene-11-ones via one-pot multi-component reactions. This novel synthetic method has the advantages of low cost and availability of the catalyst, short reaction times, high to excellent yiel...

An efficient synthesis of polyhydroquinoline derivatives was reported via four-component coupling reactions of aldehydes, 1,3-dicarbonyl ketones (dimedone or 1,3-cyclohexanedione), ethyl acetoacetate or methyl acetoacetate and ammonium acetate in the presence of a catalytic amount of nanocrystalline TiO2 under solvent free conditions. The reported method is mild, rapid and has the advantages su...

An efficient one-pot four-component protocol for the synthesis of pyrano[2,3-c]pyrazolederivatives has been demonstrated using Y(NO3)3.6H2O as catalyst under mild condition. This isa general synthetic protocol which could be applicable to a wide range of carbonyl compoundsincluding aromatic aldehydes, isatins and acenaphthenequinone. All The reactions proceededsmoothly, ...

Alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1H)-ones in high yields at 80 °C. Our results showed that Biginelli reaction not only is pH dependent, but the cation of catalyst plays an importan...

1,3-Dibromo-5,5-dimethylhydantoin (DBH), as a cheap and commercially available reagent, is efficiently able to catalyze the synthesis of polyhydroquinoline derivatives and 12-aryl-8,9,10,12-tetrahydro[a] xanthene-11-ones via one-pot multi-component reactions. This novel synthetic method has the advantages of low cost and availability of the catalyst, short reaction times, high to excellent yiel...