The four-component Hantzsch condensation reaction of dimedone, ethyl acetoacetate, ammonium acetate, and various aromatic and aliphatic aldehydes in the presence of catalytic amount of a magnetic nanoparticle-supported tribromide, as a green catalyst, under solvent‐free conditions at 80 °C affords functionalized 5-oxo-hexahydroquinolines in good to excellent yields. The magnetic Fe3O...

phosphosulfonic acid (psa) was found to be an efficient catalyst for the one-pot three-component hantzsch condensation reaction of arylaldehydes, ethylacetoacetate and ammonium acetate to afford the corresponding 1,4-dihydropyridine and polyhydroquinoline derivatives in high yields. psa was also applied for the one-pot preparation of polyhydroquinolines via four-component reaction of arylaldehy...

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...

p-dodecylbenzenesulfonic acid (dbsa) was used as a catalyst for a simple and efficient one-pot synthesis of aryl substititued tetrahydrobenzo[b]pyrans and dihydropyrano[c]chromens via initial knoevenagel, subsequent micheal and final heterocyclization reactions of aryl aldehyde, malononitrile and 4-hydroxycoumarin/dimedone in moderate to excellent yields. the present method was operationally si...

an efficient synthesis of polyhydroquinoline derivatives is achieved via hantzsch condensation reaction between aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of catalytic amount of sfhs in ethanol. this method gives remarkable advantages such as shorter reaction time, simple workup procedure and good to excellent yields. furthermore the catalyst can be recovered c...

Phosphosulfonic acid (PSA) was found to be an efficient catalyst for the one-pot three-component Hantzsch condensation reaction of arylaldehydes, ethylacetoacetate and ammonium acetate to afford the corresponding 1,4-dihydropyridine and polyhydroquinoline derivatives in high yields. PSA was also applied for the one-pot preparation of polyhydroquinolines via four-component reaction of a...

An efficient and simple procedure for the synthesis of 1,8-dioxo-octahydroxanthenes from the aromatic aldehydes and 5,5-dimethylcyclohexane-1,3-dione (dimedone) in the presence of boric acid [BO3H3 or B(OH)3] as an inexpensive and reusable catalyst is described. The salient features of this methodology are: the elimination of corrosive liquid acids, high yields, simple methodology, short reacti...

An efficient synthesis of polyhydroquinoline derivatives is achieved via Hantzsch condensation reaction between aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of catalytic amount of SFHS in ethanol. This method gives remarkable advantages such as shorter reaction time, simple workup procedure and good to excellent yields. Furthermore the catalyst can be recovered c...

p-Dodecylbenzenesulfonic acid (DBSA) was used as a catalyst for a simple and efficient one-pot synthesis of aryl substititued tetrahydrobenzo[b]pyrans and dihydropyrano[c]chromens via initial Knoevenagel, subsequent Micheal and final heterocyclization reactions of aryl aldehyde, malononitrile and 4-hydroxycoumarin/dimedone in moderate to excellent yields. The present method was operationally si...