نتایج جستجو برای: chalcones
تعداد نتایج: 1021 فیلتر نتایج به سال:
ABSTRACT. The aim of present study was the uses a series α,β-unsaturated carbonyl compounds (chalcones), in synthesis pyridine, pyran, thiophene, thiazole, together with their heterocyclic synthesis. work has resulted variety 2,5-dihydropyridine, hydrazide-hydrazone, thiophene derivatives, coumarin, pyran and thiazolo[4,5-d]thiazole derivatives. antitumor activities newly synthesized products w...
Several pyrazolo [1, 5-a] pyrimidines derivative were prepared by the condensation of substituted of α, βunsaturated carbonyl compounds (chalcones) with substituted 5-amino pyrazole as an alternative polyethylene glycol (PEG-400) as green reaction medium. The reaction is clean with excellent yield, shorter reaction time. The entire synthesized products were characterized by spectral analysis. F...
Chalcones 1~8 and 5-deoxyflavonoids 9~22 were synthesized in good yields by aldol condensation, Algar-Flynn-Oyamada reaction, glycosidation, and deacetylation reaction, respectively, starting from 2-acetyl phenols substituted by methoxy or methoxymethoxy group and appropriately benzaldehydes substituted by methoxy, methoxymethoxy group, or chlorine. Among them, 13 and 17~22 are new compounds. T...
A number of chalcones were synthesized by reacting indole-3-aldehyde, prepared by Vilsemeir Haack reaction with 4-substituted acetophenone in NaOH solution in ethanol. These chalcones were immediately reacted with urea, thiourea and guanidine hydrochloride in presence of concentrated hydrochloric acid as reagent to obtain the corresponding hydroxy, thio and amino pyrimidines. The synthesized he...
A simple, practical and efficient continuous-flow hydration-condensation protocol was developed for the synthesis of α,β-unsaturated ketones starting from alkynes and aldehydes by employing a heterogeneous catalyst in a flow microwave. The procedure presents a straightforward and convenient access to valuable differently substituted chalcones and can be applied on multigram scale.
Highly enantioselective (formal) hetero-Diels-Alder reactions between chalcones and formylcyclopropanes are disclosed. The challenging N-heterocyclic carbene (NHC)-bounded enolate intermediates from formylcyclopropanes were captured for new C-C bond forming reactions. The reaction products were obtained with high diastereo- and enantioselectivities and could be easily transformed to optically p...
• Chalcones have been examined as photoinitiators of polymerization. Polymerization processes in the visible range initiated. can be prepared one step. various monomers was possible under low light intensity. Photopolymerization is an active research field facing a revolution due to recent availability cheap, lightweight, compact and energy-saving sources that constitutes light-emitting diodes ...
A substrate-independent selective generation of enolates over homoenolate equivalents in NHC-catalyzed reactions of enals and chalcones is disclosed. Acid co-catalysts play vital roles in control of the reaction pathways, allowing for individual access to diverse products from identical substrates.
The highly efficient asymmetric Michael addition reactions of cyclopentanone with chalcones were catalyzed by a simple and commercially available chiral 1,2-diaminocyclohexane-hexanedioic acid, and exhibited good yields (up to 92%) and excellent enantioselectivities (up to 99% ee). A new di-iminium mechanism for the reaction was proposed.
A novel method for the synthesis of 2,6-dihydroxy substituted chalcones via Claisen-Schmidt is introduced using recyclable PEG-400 as an alternative reaction solvent. The reaction is clean with excellent yield, shorter reaction time and reduces the use of volatile organic compounds (VOCs). The structures of the synthesized compounds were confirmed by IR, mass spectroscopy and elemental analysis.
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