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...

a series of n-substituted-2,4-thiazolidinedione derivatives (tzds) were prepared via n-alkylation of 2,4-tzd at position 3 using substituted benzyl halides. synthesized n-substituted-2,4-tzd was then substituted at position 5 with substituted aromatic aldehyde according to knoevenagel condensation method. structures of the compounds were elucidated using various spectral techniques viz. ir, 1hn...

A series of N-substituted-2,4-thiazolidinedione derivatives (TZDs) were prepared via N-alkylation of 2,4-TZD at position 3 using substituted benzyl halides. Synthesized N-substituted-2,4-TZD was then substituted at position 5 with substituted aromatic aldehyde according to Knoevenagel condensation method. Structures of the compounds were elucidated using various spectral techniques viz. IR, 1HN...

Visible light induced a highly efficient and environmentally-friendly Knoevenagel condensation of various aliphatic and aromatic aldehydes with malononitrile has been achieved in excellent yield in presence of aqueous tamarind juice. The tamarind juice could be simply prepared from unripe fruit of Tamarindus indica in water and the reactions go to completion within 2-7 min. A plausible mechanis...

A novel one-pot aerobic oxidation/Knoevenagel condensation reaction system was developed employing a Cu(ii)/amine bifunctional, basic metal-organic framework (MOF) as the catalyst. The sequential aerobic alcohol oxidation/Knoevenagel condensation reaction was efficiently promoted by the Cu3TATAT MOF catalyst in the absence of basic additives. The benzylidenemalononitrile product was produced in...

The mechanism of the TiCl4-promoted condensation of methyl acetoacetate, isobutyraldehyde, and indole was studied by a combination of theoretical and experimental techniques. The energy profile of plausible reaction paths was evaluated by DFT calculations, and various reaction intermediates were isolated or observed in solution by NMR spectroscopy. Theoretical and experimental results indicate ...

Catalytic behavior of isomorphously substituted B-, Al-, Ga-, and Fe-containing extra-large pore UTL zeolites was investigated in Knoevenagel condensation involving aldehydes, Pechmann condensation of 1-naphthol with ethylacetoacetate, and Prins reaction of β-pinene with formaldehyde and compared with large-pore aluminosilicate zeolite beta and representative Metal-Organic-Frameworks Cu3(BTC)2 ...

Starting from aromatic ortho-dialdehydes, we devised a homo-elongation protocol that combines a Wittig olefination and subsequent intramolecular Knoevenagel condensation to produce acene diesters and dinitriles.

A porous molecular crystalline solid based on amide-containing Pd(II) triangles was created for size-selective heterogeneous catalysis of the Knoevenagel condensation reaction.

the knoevenagel condensation of aromatic aldehydes with barbituric acid, dimedone and malononitrile occurred in the presence of bf3/nano-γ-al2o3 at room temperature in ethanol. this catalyst is characterized by powder x-ray diffraction (xrd), fourier transform infrared spectroscopy (ft-ir), thermal gravimetric analysis (tga), field emission scanning electron microscopy (fesem) and energy-disper...