10.1016/j.tetlet.2004.09.136
The study focuses on the reactivity of substituted pyridinium N-(20-azinyl)aminides in the Suzuki–Miyaura cross-coupling reaction, a widely used method for forming sp2–sp2 carbon–carbon bonds. The researchers investigated the coupling of these compounds with various boronic acids, using Cs2CO3 as a base, which resulted in good yields and substitution on the negatively charged moiety. They optimized the reaction conditions and found that the process was efficient for a range of substrates, including those with electron-deficient diazine rings, albeit requiring longer reaction times. The study also explored a double Suzuki process with a dibromoaminide to yield diarylated ylides. The results provide a valuable strategy for the synthesis of functionalized 2-aminoazines, which are important in medicinal and heterocyclic chemistry, and the researchers are continuing their efforts to expand the application of this process to other N-aminides.
10.1016/j.tetlet.2012.07.093
The study describes a new and efficient method for synthesizing indolo[3,2,1-jk]carbazoles through palladium-catalyzed intramolecular cyclization of N-(2-bromoaryl)carbazoles. The reaction involves forming carbon-carbon bonds via intramolecular arylation, which proceeds with the cleavage of C–X and C–H bonds on the carbazole ring. Various substituted N-aryl carbazole substrates, containing both electron-donating and electron-withdrawing groups, were explored under optimized conditions. The study successfully yielded indolo[3,2,1-jk]carbazoles with high thermostability, good fluorescence properties, and electron-donor potential, making them promising candidates for applications in organic electronics and material chemistry.
10.1021/ja1084749
The study conducted by Roland Appel, Nicolai Hartmann, and Herbert Mayr from the Department of Chemistry at Ludwig-Maximilians-Universit?t München, investigates the cyclopropanation reactions using sulfur ylides. It focuses on the rates of reactions between stabilized and semistabilized sulfur ylides with benzhydrylium ions and Michael acceptors, measured using UV-vis spectroscopy in DMSO at 20°C. The research establishes a correlation between the second-order rate constants (log k2) and the electrophilicity parameters (E) of the electrophiles, which aids in calculating the nucleophile-specific parameters (N and s) for the sulfur ylides. The findings indicate that the rate constants for cyclopropanation reactions with Michael acceptors align with those for carbocations, suggesting a stepwise mechanism with the initial nucleophilic attack being rate-determining. This study provides a quantitative approach to understanding sulfur ylide reactivity, which is crucial for predicting the scope and limitations of cyclopropanation reactions in organic synthesis.
10.1021/om100673e
The study presents the synthesis and characterization of silver and palladium complexes with xanthene-based N-heterocyclic carbene-oxazoline ligands. The researchers synthesized xanthenes with two different donor ligand units, N-heterocyclic carbene (NHC) and oxazoline, and prepared silver complexes 15 and 19 by reacting the xanthene derivatives with Ag2O. They also synthesized palladium complexes 16 and 20 by reacting the corresponding silver complexes with Pd(PhCN)2Cl2. X-ray crystallographic analysis revealed that complexes 15-PF6, 16, and 20 adopted trans configurations, while the Ag atom of 15-Cl coordinated only to the NHC ligand. The study provides insights into the structural analysis of these complexes, which could be significant for the development of catalysts for various reactions, particularly asymmetric synthesis.
10.1080/10587250307066
The research presents the synthesis and characterization of a new mesogenic homologous series of Schiff base cinnamates that incorporate a naphthalene moiety. The study aimed to understand the impact of the ethylene linking group (cinnamoyl linkage) and the naphthalene moiety on the mesomorphic properties of these molecules. The reactants used in the synthesis included 4-(40-n-alkoxy cinnamoyloxy) benzaldehydes, 2-amino naphthalene, malonic acid, n-alkyl halide, K2CO3, p-hydroxy benzaldehyde, and solvents like ethanol, which were dried prior to use. The synthesized compounds were characterized using elemental analysis and various spectroscopic techniques, including infrared (IR), ultraviolet (UV), and proton nuclear magnetic resonance (1H NMR) spectroscopy. The study found that all synthesized compounds exhibited mesomorphism, and the mesophase properties were compared with other structurally related series. The results indicated that the presence of the naphthalene moiety and the cinnamoyl linkage influenced the mesophase transition temperatures and the overall thermal stability of the mesophases.
10.1016/j.ejmech.2008.02.021
The research focuses on the synthesis and evaluation of new analogues of 2-[2-substituted-3-(3,4-dichlorobenzylamino)propylamino]quinolin-4-ones as inhibitors of Staphylococcus aureus methionyl-tRNA synthetase, an enzyme crucial for protein synthesis and a promising target for antibacterial drug development. The study involves the synthesis of various compounds through a series of chemical reactions, including amination, removal of protective groups, and reductive alkylation, using reactants such as 2-chloro-4-(4-methoxybenzyloxy)quinoline, 2-substituted 1,3-diamines, K2CO3, and 3,4-dichlorobenzaldehyde. The synthesized compounds were then evaluated for their in vitro inhibitory activity against the target enzyme and their antibacterial activities against various strains of S. aureus and Enterococci. The experiments utilized techniques such as silica gel column chromatography, NMR spectroscopy, and mass spectrometry for compound purification and characterization. The minimum inhibitory concentrations (MICs) of the compounds were determined using the microdilution method with Mueller-Hinton Broth and Brain Heart Infusion Broth, following the Clinical and Laboratory Standards Institute (CLSI) guidelines. The study aimed to develop new antibiotics to combat drug-resistant bacteria, including methicillin-resistant S. aureus (MRSA) and vancomycin-resistant Enterococci (VRE).
10.1021/jm0607101
The research focuses on the synthesis and evaluation of a series of lipophilic polyamines for DNA delivery and transfection efficiency. These polyamines, containing varying chain lengths and structures, were covalently attached to a 3,4-bis(oleyloxy)-benzyl motif and additionally linked via amide linkers for some derivatives. The study aimed to understand how the number and position of positive charges along the polyamine scaffold influence DNA delivery and transfection efficiency, competing with commercially available transfection reagents like Lipofectamine 2000. The experiments involved synthesizing the polyamine derivatives, evaluating their cytotoxicity in Chinese hamster ovary (CHO) cells, assessing their DNA delivery capabilities using AlexaFluor-488-labeled DNA, and measuring green fluorescent protein (GFP) expression after transfection with an eGFP DNA plasmid. Reactants used in the synthesis included 3,4-bis(oleyloxy)benzaldehyde, oleyl bromide, potassium carbonate, and various amines, while analyses were performed using techniques like NMR spectroscopy, high-resolution mass spectrometry, and flow cytometry to assess DNA uptake and GFP expression.
10.1007/s12039-012-0354-x
The research focuses on the synthesis and evaluation of a series of 2-(3-methyl-2-oxoquinoxalin-1(2H)-yl)acetamide-based azetidinone derivatives as potential antibacterial and antifungal agents. The study involved the synthesis of twelve compounds, which were subjected to in vitro antibacterial testing against E. coli, S. aureus, K. pneumoniae, P. aeruginosa, and antifungal testing against C. albicans, A. niger, and A. flavus using the cup-plate method. The synthesized compounds were confirmed through spectral data interpretation, including Fourier Transform-Infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (1H-NMR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and elemental analysis. The experiments utilized various reactants such as pyruvic acid, o-phenylenediamine, ethylchloroacetate, potassium carbonate, and different aromatic aldehydes, along with chloroacetylchloride and triethylamine for the final compound formation. The structures of the synthesized compounds were elucidated using these analytical techniques, and their biological activities were assessed and compared with standard drugs to determine their potential as antimicrobial agents.
10.1080/00397919108021779
The study presents a method for the synthesis of substituted N-monoalkylaromatic amines under phase-transfer catalysis (PTC) conditions. The researchers used various aromatic amides and amines as starting materials, which were converted to N-monoalkylated products using dimethyl sulphate as the alkylating agent. The reaction was facilitated by the presence of powdered sodium hydroxide, potassium carbonate, and tetrabutylammonium hydrogen sulphate as the PTC. The study found that compounds with ortho electron-withdrawing substituents exclusively yielded monoalkyl amines, while those with electron-donating substituents or no substituents resulted in alkyl amides. The researchers proposed a mechanism for the alkylation and deacylation processes and verified it experimentally. The study provides a simple, economical one-pot synthesis method for producing ortho substituted aromatic monoalkyl amines with electron-withdrawing substituents.
10.1021/jo010703e
The study describes a practical synthesis of a second-generation benzoin photolabile safety-catch (BPSC) linker for solid-phase organic synthesis (SPOS). The new linker, featuring a carboxylic acid functionality for resin attachment and a four-carbon tether for enhanced stability, can be loaded onto amine-terminating resins or preloaded with substrates in solution before resin immobilization. This approach offers improved control over linker loading and substrate attachment, making it versatile for SPOS applications. The research highlights the synthesis process, resin attachment, and photolytic cleavage efficiency, demonstrating the linker's potential utility in complex organic synthesis.
10.1021/ol202582c
The study presents an efficient method for the N-alkylation of sulfonamides and amines using alcohols as alkylating reagents, catalyzed by manganese dioxide (MnO2) under aerobic and solvent-free conditions. This approach is a greener alternative to traditional methods, as it avoids the use of noble metal catalysts, preformed complexes, and inert atmosphere protection. The researchers found that MnO2 is a less toxic, readily available, and recyclable catalyst that can facilitate the reaction at mild temperatures without the need for high pressure or large excess amounts of reagents. The method was successfully applied to a variety of sulfonamides and amines, yielding good to high product yields. Additionally, the study explores the potential mechanism of the reaction, suggesting a process involving Mn-mediated alcohol oxidation, condensation, transfer hydrogenation, and regeneration of the aldehyde, which completes the catalytic cycle. The developed method simplifies operation and workup procedures and may serve as a promising alternative to existing N-alkylation methods.
10.1039/c4ob02208d
The research focuses on the development of a mild and efficient method for the conversion of arylboronic acids into arylthiocyanates using a copper-catalyzed aerobic oxidative process. The study employs trimethylsilylisothiocyanate (TMSNCS) as a thiocyantion reagent and utilizes NaF as a promoter under an oxygen atmosphere, with CuCl serving as the catalyst. The cross-coupling reaction is conducted at ambient temperature and is found to be effective for a broad range of functional groups, including strong electron-withdrawing groups. The experiments involve the optimization of reaction conditions, including the evaluation of various catalysts, ligands, additives, and solvents, ultimately leading to the identification of an optimal condition that involves the use of 20 mol% CuCl, 20 mol% TMEDA as a ligand, 1 equiv. of NaF, and 4 equiv. of K2CO3 in acetonitrile at room temperature for 12 hours, with 3? molecular sieves. The substrate scope was also investigated, demonstrating the versatility of the method with both electron-donating and electron-withdrawing arylboronic acids. The reaction mechanism is proposed based on the formation and reactivity of CuSCN as an intermediate, with both TMEDA and O2 being essential for the transformation. The study concludes that the developed protocol offers a milder and more efficient approach for aromatic oxidative thiocyanation, with potential applications in the synthesis of a variety of aryl thiocyanates.
10.2174/157017811799304098
The research focuses on the efficient synthesis of 1,4-disubstituted piperazine-2,5-diones, which are significant as biologically active natural products and important in drug discovery. The study developed a simple and efficient method for their synthesis using potassium iodide catalysis in aqueous media, specifically in an acetone/water mixture. The reactants used were N-substituted chloroacetamides, potassium carbonate as a base, and potassium iodide as a catalyst. The experiments involved refluxing these reactants and optimizing conditions to achieve high yields of the desired piperazinediones. The structures of the synthesized products were confirmed through elemental analyses, infrared (IR), proton (1H) and carbon-13 (13C) nuclear magnetic resonance (NMR) spectroscopy, and in some cases, single crystal X-ray diffraction analysis. The article also discusses the influence of solubility and steric hindrance on the reaction yields and mentions ongoing investigations into the biological activities of these compounds.
10.1007/s00044-010-9411-5
The research focuses on the design, synthesis, and evaluation of novel substituted-piperazine analogues for their antiplatelet aggregation activity, which is crucial for managing cardiovascular and thromboembolic diseases. The study involves the synthesis of new carbamoylpyridine and carbamoylpiperidine analogues containing a nipecotic acid scaffold, with a series of chemical reactions utilizing reactants such as nicotinoyl chloride, various aryl and aroyl-piperazines, alkyl or aroylhalides, and potassium carbonate. The synthesized compounds were evaluated for their inhibitory activity against platelet aggregation using different agonists like ADP, adrenaline, collagen, arachidonic acid, and ristocetin. The experiments included quaternization, catalytic hydrogenation, and molecular modeling investigations to understand the structure-activity relationship and the impact of lipophilicity on activity. The most active compounds identified were N1-[1-(4-bromobenzyl)-3-piperidino-carbonyl]-N4-(2-chlorophenyl)-piperazine hydrobromide (20) and 1,4-bis-[3-[N4-(2-chlorophenyl)-N1-(piperazino-carbonyl)]-piperidin-1-yl-methyl]-benzene dibromide (30), both exhibiting significant antiplatelet aggregating effects at a concentration of 0.06 μM. The analyses included NMR spectroscopy, mass spectrometry, and molecular docking studies to elucidate the compounds' structures and their interactions with the thrombin receptor.
10.1016/j.tet.2006.12.082
The research focuses on the molecular engineering of organic dyes containing the N-aryl carbazole moiety for application in solar cells, specifically dye-sensitized solar cells (DSSCs). The purpose of this study was to design and synthesize novel organic dyes that could overcome the limitations of low conversion efficiency and operational stability often associated with organic dyes in DSSCs, as compared to metal-based complexes. The researchers aimed to develop alternative, highly efficient organic dyes that could potentially rival the performance of ruthenium complexes, which are known for their high efficiency but are prohibitively expensive. In the process, various chemicals were used, including 2-iodo-9,9-dimethylfluorene, 3-iodocarbazole, 1-bromo-4-(2,2-diphenylvinyl)benzene, and (2-thienylmethyl)triphenylphosphonium bromide, which were synthesized using modified procedures from previous references. Other chemicals involved in the synthesis steps included tributyl(thiophen-2-yl)stannane, Pd(PPh3)4, copper bronze, potassium carbonate, 18-crown-6, n-butyl lithium, cyanoacetic acid, piperidine, rhodanine-3-acetic acid, and ammonium acetate, among others. These chemicals were utilized in a series of reactions such as coupling, lithiation, and condensation to synthesize the target dyes, which were then tested for their photovoltaic performance in DSSCs.
10.1021/ol8029627
The study presents an efficient method for nucleophilic fluoromethylation of alkyl and benzyl halides using fluorobis(phenylsulfonyl)methane (1) as a versatile reagent. The researchers achieved stereospecific one-pot synthesis of fluorovinyl compounds such as fluorostyrylsulfones, fluorocinnamates, and fluorochalcones using benzyl halides. The methodology was extended to synthesize R-substituted fluoroalkane derivatives through selective reductive desulfonylation. The study highlights the importance of fluorine in modifying the physicochemical and pharmacokinetic properties of drug molecules. The researchers used mild bases like potassium carbonate in DMF or cesium carbonate in acetonitrile to generate the soft carbanion [R-fluorobis(phenylsulfonyl)methide] from R-fluorobis(phenylsulfonyl)methane, which then reacted with primary alkyl iodides and bromides to produce alkylated products in moderate to excellent yields. For benzyl halides, the reaction led to the formation of fluorovinyl sulfones, indicating a second elimination step. The study also explored reductive desulfonylation using a Mg/HOAc/NaOAc system for monodesulfonylation and a Mg/MeOH system for didesulfonylation, yielding R-fluoro-R-(phenylsulfonyl)alkanes and R-fluoroalkanes, respectively.
Xn
Xn:Harmful;
