Refernces
10.1021/ja076797c
The study presents a novel catalytic asymmetric cyclopropanation reaction of enones using dimethyloxosulfonium methylide, promoted by a La-Li3-(biphenyldiolate)3 + NaI complex. The reaction showcases high enantioselectivity, with up to 99% ee, and is applicable to a variety of enones, including those with electron-withdrawing or electron-donating substituents and heteroaryl-substituted enones. The use of NaI as an additive, along with biphenyldiol as a ligand, is crucial for achieving this level of selectivity. The reaction conditions were optimized to allow for slow addition of enones, which further improved the enantioselectivity. The study also explores the potential of the catalyst system with other substrates, such as an N-acylpyrrole, and discusses the role of NaI in the reaction mechanism, suggesting a partial alkali metal exchange occurs in situ to form a La-Li2-Na-(biphenyldiolate)3 complex. The findings provide a complementary approach to existing methods for catalytic asymmetric cyclopropanation and highlight the importance of the mixed-alkali metal system in achieving high yields and enantioselectivity.
10.1021/acs.organomet.8b00410
The study focuses on the synthesis and characterization of a series of low-valent molybdenum complexes supported by the pincer ligand (iPr2PCH2CH2)2NH, which were prepared and found to be effective catalysts for the hydrogenation of ketones and olefins. The researchers utilized various chemicals, including Mo(CO)6, NaBHEt3, different acetophenones, chalcone, styrenes, and other substrates for hydrogenation reactions. These chemicals served as precursors for the molybdenum complexes, reducing agents, and substrates to test the catalytic activity of the synthesized complexes. The purpose of these chemicals was to facilitate the creation of new Mo(PNP) pincer complexes and to evaluate their performance in catalytic hydrogenation reactions, which are important in homogeneous catalysis and industrial applications.
10.1039/c5ra10140a
The study investigates the molecular structure and electrochemical behavior of a series of methoxylated 2'-hydroxychalcones, which are known for their antitumor activity. The research aims to correlate experimental electrochemistry with theoretical calculations, focusing on the role of intramolecular hydrogen bonds (IHBs) in these compounds. Cyclic voltammetry was employed to characterize the formation and stability of anion radicals, while density functional theory (DFT) calculations were used to investigate the molecular structures of the neutral compounds and their anion radicals, particularly the IHBs. The study also calculated adiabatic and vertical electron affinities (AEA, VEA), vertical detachment energy (VDE), and used natural bond orbital (NBO) analysis to gain insights into the electronic characteristics of the IHBs. The purpose of using these chemicals was to understand their redox properties and how the methoxy substitution pattern affects the IHB and redox behavior, which has implications for the design of antitumor chalcones.
10.1016/S0040-4039(01)01793-2
The research focuses on the novel synthesis of 24-membered macrocycles with chalcone structural moieties and isobutenyl ether linkages in the core, which are significant for molecular recognition and photophysical properties. The purpose of this study is to incorporate chalcone moieties into macrocyclic structures, leveraging their well-exploited photophysical properties for various optical applications. The researchers envisioned that these macrocycles could be useful for molecular recognition studies and as photo-functional materials. The synthesis strategy involved a mixed aldol reaction of bis-arylaldehyde and bis-arylmethyl ketone, expected to yield a macrocycle with two chalcone moieties and two isobutenyl ether linkages. The study successfully demonstrated a novel approach to synthesize these macrocycles, which possess potential for further modifications under thermal conditions, as shown in the conversion of macrocycle 8a to 9a. The chemicals used in the process include t-BuOK as a catalyst, THF as a solvent, and various substituted aryl groups on the aldehyde and ketone compounds, such as chloro, methoxy, and methyl groups. The synthesized macrocycles were fully characterized using IR, NMR, and ESI-MS techniques. The conclusions drawn from the research indicate that the presence of two isobutenyl ether linkages in the macrocycles are useful for modifications of the macrocycle core under thermal conditions, and the photophysical and molecular recognition properties of these macrocycles will be the focus of future studies.
10.1155/2012/525940
The research focuses on the synthesis and spectroscopic characterization of new biologically active Azo-Pyrazoline derivatives. The purpose of this study was to create a series of compounds that have potential applications in the field of medicine, specifically as antimicrobial agents, by combining aromatic rings through an Azo-coupling reaction and further synthesis. The researchers synthesized several 3-[4-(benzyloxy)-3-(2-Chlorophenylazo)-phenyl]-5(substituted-phenyl)-1-substituted-2-pyrazolines (4a-j) and (5a-j) through a series of chemical reactions involving diazotization of 2-chloroaniline, coupling with 4-hydroxy acetophenone, benzyloxation, and Michael addition with hydrazine hydrate. The synthesized compounds were then characterized using FT-IR, 13C-NMR, 13C-DEPT, and 1H-NMR spectral data to confirm their structures. The study concluded that these chalcone and pyrazoline derivatives showed significant antibacterial activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria. The chemicals used in the process included 2-chloroaniline, 4-hydroxy acetophenone, benzyl bromide, various substituted benzaldehydes, hydrazine hydrate, and phenylhydrazine, among others.
10.1246/cl.1992.535
The research focused on the unusual reaction of chalcone derivatives with aromatic aldehydes, promoted by ytterbium metal. The purpose of the study was to investigate the cyclodimerization of chalcone derivatives and the role of ytterbium metal in promoting the reaction, which led to the formation of cyclopentanols or cyclopentanones. The researchers observed that the reaction yielded different products depending on the amount of aldehyde used: with an equimolar amount of benzaldehyde, they obtained 2-benzoyl-5-phenylhydroxymethyl-1,3,4-triphenylcyclopentanol, while an excess of aldehyde resulted in 2,5-bis(benzoyl)cyclopentanol. Key chemicals used in the process included chalcone, benzaldehyde, anisaldehyde, and ytterbium metal, with solvents like THF-HMPA employed in the reactions. The conclusions drawn from the study indicated that the cyclodimerization of chalcone derivatives promoted by ytterbium metal involves dianion species, with the negative charge unexpectedly distributed on oxygen and carbon-5 of the cyclopentanol rings, leading to the selective formation of products at the C-5 position.
10.1134/S1070363216070288
The research focuses on the synthesis and antimicrobial evaluation of a series of tricyclic macrocycles containing a chalcone moiety. The purpose of this study is to explore the potential of these macrocycles as novel antimicrobial agents. The researchers synthesized the tricyclic scaffolds in two stages. Initially, they used the Claisen–Schmidt condensation of substituted 2-hydroxyacetophenones and salicylaldehyde in the presence of potassium hydroxide to obtain chalcones. In the second stage, these chalcones were treated with various dibromoalkanes in the presence of anhydrous potassium carbonate in DMF to form the tricyclic compounds. The synthesized compounds were characterized using IR, NMR spectroscopy, and mass spectrometry. The antimicrobial activity was tested against several bacterial and fungal strains, with some compounds showing significant inhibitory activity. The study concludes that the synthesized tricyclic macrocycles could serve as an attractive template for identifying new antimicrobial agents, highlighting the potential of incorporating chalcone moieties into macrocyclic structures for enhancing biological activity.
10.1039/d0ob01149e
The study presents a novel nucleophilic methylthiolation methodology that enables the incorporation of the CH3S- group into activated carbons through either conjugate additions or substitutions reactions. The researchers utilized a range of chemicals, including chalcones, acyl ester derivatives, Morita-Baylis-Hillman acetates, and methylthiomethyl esters as the primary substrates and reagents. Methanethiol, traditionally used for methylthiolation, was replaced with these novel reagents due to its flammability and toxicity. The study aimed to develop a safer, low-cost, transition-metal-free method that exhibits good group tolerance and yields moderate to excellent results. Key chemicals involved in the reaction mechanism include potassium trichloroacetate, acetic acid, and camphorsulfonic acid (CSA) as an organocatalyst. The reaction products were further utilized to synthesize sulfoxides and sulfones, demonstrating the synthetic utility of the methodology. The study also involved theoretical calculations using Density Functional Theory to investigate the reaction mechanism, confirming the role of sulfurane and sulfonium ylide as key intermediates and the importance of a Pummerer rearrangement in the formation of the reagent.
Xn
