نتایج جستجو برای: knoevenagel
تعداد نتایج: 502 فیلتر نتایج به سال:
An 1,3-indanedione-derived donor–acceptor cyclopropane, bearing the ethoxymethyl-protected phenolic group at ortho-position of donor aryl substituent, has been synthesized using a reaction sequence involving Knoevenagel condensation 1,3-indanedione with corresponding protected salicylaldehyde followed by Corey–Chaykovsky cyclopropanation obtained adduct dimethylsulfoxonium methylide. The struct...
An efficient one-pot three-component protocol for the synthesis of novel tetrahydrobenzofuran-chromone conjugates using 3-formylchromones and 1,3-cyclohexandiones in presence a variety alkyl or aryl isocyanides was developed. The reaction sequence consists an initial Knoevenagel condensation aromatic aldehydes with 1,3-cyclohexandione derivatives, followed by [4 + 1] cycloaddition isocyanides, ...
The ionic liquid 1,3-dimethylimidazolium methyl sulfate, [MMIm][MSO₄], together with a small amount of water (the amount taken up by the ionic liquid upon exposure to air), acts efficiently as both solvent and catalyst of the Knoevenagel condensation reactions of malononitrile with 4-substituted benzaldehydes, without the need for any other solvent or promoter, affording yields of 92%-99% withi...
Couturier, F. (1910). C.R. Acad. Sci., Paris, 150, 928. Geiger, W. B. & Conn, J. E. (1945). J. Amer. chem. Soc. 67, 112. Knoevenagel, E. (1894). Liebigs Ann. 281, 48. Kohler, E. P. & Woodward, D. W. (1936). J. Amer. chem. Soc. 58, 1933. Meyer, K. H. (1913). Liebigs Ann. 398, 49. Pechmann, H. von (1882). Ber. dtsch. chem. Ges. 15, 881. Puetzer, B., Nield, C. H. & Barry, R. H. (1945). Science, 10...
rel-(5aR,11bR)-3,5a,6,11b-tetrahydro-2H,5H-chromeno[4',3':4,5]thiopyrano[2,3-d][1,3]thiazol-2-ones formed by the stereoselective Knoevenagel-hetero-Diels-Alder reaction were functionalized at the nitrogen in position 3 via reactions of alkylation, cyanoethylation, and acylation. The synthesized compounds were evaluated for their anticancer activity in NCI60 cell lines. Among the tested compound...
A series of Pyrano[2,3-d]Pyrimidine derivatives were synthesis using Knoevenagel and Michael addition reaction. Investigation of antimicrobial properties were done against gram positive bacteria Staphylococcus(NCTC-7447),Bacillus cereus(ATCC-14579) and gram negative bacteria Serratia maresens(IMRU-70), Proteus merabitis (NTCC-289) using Ampicillin as standard drugs. These synthesized compounds ...
An efficient synthesis of 2-hydroxy-2-(trifluoromethyl)-2H-chromene-3-carboxylates was carried out under solvent-free conditions in an oven or microwave oven via the Knoevenagel condensation of salicylaldehydes with ethyl trifluoroacetoacetate followed by intramolecular cyclization in the presence of silica-immobilized L-proline. The structures of the title compounds were characterized by IR, ¹...
Simple primary-tertiary diamines easily derived from natural primary amino acids were used to catalyze the Michael addition of ketones with isatylidenemalononitrile derivatives. Diamine 1a in combination with D-CSA as an additive provided Michael adducts in high yield (up to 94%) and excellent enantioselectivity (up to 99%). The catalyst 1a was successfully used to catalyze the three-component ...
The Acylase "Amano" (AA)-catalyzed synthesis of valuable pyridin-2-ones via domino Knoevenagel condensation-Michael addition-intramolecular cyclization-oxidization reaction between aldehyde, cyanoacetamide and ethyl acetoacetate or cyclohexyl acetoacetate was developed in the sense of a one-pot strategy. Various aliphatic, aromatic and hetero-aromatic pyridin-2-ones could also be produced in th...
In our effort to obtain biologically active compounds, new 3,5-disubstituted 1,3-thiazolidine-2,4diones (5a – r) were synthesized. A series of 5-arylmethylidene-1,3-thiazolidine-2,4-diones (3a – r) were prepared by Knoevenagel reaction from 1,3-thiazolidine-2,4-dione (2) and appropriate aromatic aldehydes. Condensation of 3a – r with 7-hydroxy-4-bromomethyl-2-oxo-2H-chromene (1) afforded novel ...
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