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...

(diacetoxyiodo)benzene has been used as an efficient catalyst for an improved and rapid one-pot synthesis of biscoumarin derivatives in excellent yield under reflux condition using water as a environmentally benign reaction medium. this aqua mediated knoevenagel condensation of various aromatic and hetero-aromatic aldehydes with 4-hydroxycoumarin using catalytic amount of (diacetoxyiodo)benzene...

ABSTRACT Knoevenagel condensation of barbituric acids with aromatic aldehydes containing one or two formyl groups was carried out. 5-Arylidenebarbituric acids underwent smooth hetero-Diels-Alder (HDA) reactions with enol ethers to afford cis and trans diastereoisomers of pyrano[2,3-d]pyrimidine-2,4-diones and 5,5'-(1,4-phenylene)bis[2H-pyrano[2,3-d]pyrimidine-2,4(3H)-dione] derivatives in excel...

nano tin dioxide was employed as a catalyst for efficient and facile preparation of pyran derivatives via the one-pot three component condensation reaction of various aldehydes with malononitrile and dimedone. chromene derivatives via the one-pot three component condensation reaction of various aldehyde with malononitrile and 4-hydroxycoumarin were also synthesized by this novel catalyst. the d...

(Diacetoxyiodo)benzene has been used as an efficient catalyst for an improved and rapid one-pot synthesis of biscoumarin derivatives in excellent yield under reflux condition using water as a environmentally benign reaction medium. This aqua mediated Knoevenagel condensation of various aromatic and hetero-aromatic aldehydes with 4-hydroxycoumarin using catalytic amount of (diacetoxyiodo)benzene...

(Diacetoxyiodo)benzene has been used as an efficient catalyst for an improved and rapid one-pot synthesis of biscoumarin derivatives in excellent yield under reflux condition using water as a environmentally benign reaction medium. This aqua mediated Knoevenagel condensation of various aromatic and hetero-aromatic aldehydes with 4-hydroxycoumarin using catalytic amount of (diacetoxyiodo)benzene...

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...

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...

efficient and one-pot synthesis of 1,8-dioxo-octahydroxanthenes was described by knoevenagel condensation, michael addition and cyclodehydration of dimedone. this reaction was carried out through condensation of dimedone and various aromatic aldehydes in the presence of task-specific brønsted acidic ionic liquid under solvent free conditions. the catalyst could be recycled five times without si...