10.1002/chem.201701346
The study focuses on the photocatalyzed synthesis of alkylpyridines using vinylpyridines as building blocks. The researchers utilized a decatungstate salt as a photocatalyst to facilitate the addition of various hydrogen donors, such as ethers, aldehydes, alkanes, and amides, onto vinylpyridines under sunlight or flow conditions. This approach successfully yielded alkylpyridines, which are significant as they serve as building blocks for compounds with biological activity, including those with potential pharmaceutical uses and umami flavor. The process is straightforward, cost-effective, and environmentally friendly, as it minimizes the use of harmful reagents and can be conducted using natural sunlight, showcasing the potential for green and sustainable chemical synthesis.
10.1081/SIM-100002039
The research focuses on the synthesis and characterization of a linear pentadentate ligand, N-(2-hydroxyethyl)-N′′-(2-hydroxybenzyl)-diethylenetriamine (HL), and its zinc(II) complex. The study investigates the promoted hydrolysis of 4-nitrophenyl acetate (NA) by the zinc(II) complex. The ligand and its complex were synthesized using reagents like 2-chloroethanol, diethylenetriamine, and salicylaldehyde, and characterized using IR spectra, 1H NMR spectra, and elemental analyses. The protonation constants of HL and the stability constants of its Zn(II) complexation were determined through pH potentiometric titration at 25°C and I = 0.1 mol/L KNO3. The kinetics of NA hydrolysis catalyzed by the complex were studied spectrophotometrically at 25°C and I = 0.1 mol/L KNO3 in a CH3CN solvent, with the second-order rate constants (kc) for NA hydrolysis being obtained. The experiments involved the preparation of the ligand and its complex, pH titration to determine protonation and complexation equilibria, and kinetic studies to measure the rate of NA hydrolysis catalyzed by the complex.
10.1016/j.tetlet.2008.01.008
The research focuses on the synthesis of 2-substituted 2H-chromenes, which are important oxygenated heterocyclic compounds with potential applications as inhibitors for TGF-b receptors. The synthesis is achieved using potassium vinyltrifluoroborates and salicylaldehyde in the presence of secondary amines, specifically dibenzylamine, at 80°C in dimethylformamide (DMF). The reactants include various substituted salicylaldehydes and potassium vinylboronic acids. The products, 2-substituted 2H-chromene derivatives, are obtained with yields ranging from 51% to 90%. The analyses used to characterize the synthesized compounds include thin layer chromatography, 1H NMR, 13C NMR, and high-resolution mass spectrometry, which confirm the purity and structure of the products.
10.1016/j.saa.2013.10.086
The study focuses on the synthesis and evaluation of novel azo dye-thiosemicarbazone derivatives (sensors 3a–f) as selective colorimetric chemosensors for anion detection, particularly for acetate anions. These sensors were synthesized through a condensation reaction between thiosemicarbazide and various azo salicylaldehydes. The chemicals used in the study include thiosemicarbazide, azo salicylaldehydes, and tetra-n-butylammonium salts of different anions (acetate, fluoride, chloride, iodide, and dihydrogenphosphate). The purpose of these chemicals was to create a series of sensors that could selectively recognize and detect acetate anions over other anions through a visible color change, which was confirmed by spectroscopic methods and UV–vis spectra. The study demonstrated that sensor 3e, with a nitrophenyl substituent, showed the most remarkable color change and selectivity for acetate anions, making it a potential candidate for practical analysis and application in detecting acetate ions in aqueous solutions.
10.1002/ejic.201500489
This research aimed to develop a colorimetric sensor for the detection of spermine, a biogenic amine, using the CuII complex of an imine-based organic nanoaggregate in aqueous medium. The study synthesized a Schiff-base receptor from dipicolinic acid hydrazide and characterized it using various spectroscopic techniques. The receptor was then processed into organic nanoaggregates (O1) and tested for metal ion recognition, showing selectivity for Cu2+. The CuII complex (O1·Cu2+) was used as a sensor for detecting biogenic amines, demonstrating selective sensing of spermine with a detection limit of 7.62 nM. The sensor exhibited a color change upon addition of spermine, which could be observed with the naked eye, and was stable within the physiological pH range. The chemicals used in the process included dipicolinic acid hydrazide, salicylaldehyde, and various metal nitrate salts for testing metal ion selectivity. The study concluded that the developed organic nanoaggregates could selectively chemosense spermine in aqueous medium, with the detection limit and UV/Vis spectral profile confirming the effectiveness of the O1·Cu2+ complex for this purpose.
10.1016/j.tetlet.2010.06.014
The research focuses on the development of an efficient and straightforward method for the synthesis of new benzopyranopyrimidines, which are compounds known for their anti-inflammatory, analgesic, and in vitro anti-aggregating activities, and have potential cytotoxic effects against cancer cell lines. The study reports a pseudo four-component reaction involving salicylic aldehydes, malononitrile, and various amines in the presence of a catalytic amount of lithium perchlorate (LiClO4) as a catalyst in ethanol (EtOH) at room temperature. The method offers mild reaction conditions, high product yields, and operational simplicity. The researchers tested different Lewis and protic acid catalysts and solvents to optimize the reaction conditions, ultimately achieving the best yield (93%) with LiClO4 in EtOH. The synthesized compounds were characterized by IR, 1H and 13C NMR spectroscopy, and elemental analysis, confirming the structure and purity of the products. The study concludes that this new procedure provides an efficient and simple pseudo four-component method for the synthesis of (5H-benzopyrano[2,3-d]pyrimidin-2-yl)phenols, which could be valuable in the growth of benzopyranopyrimidine chemistry.
10.1002/adsc.201000895
The study presents an efficient method for the one-pot copper(I)-catalyzed synthesis of 3-aminocoumarin and its derivatives, which are biologically and pharmaceutically significant compounds. The researchers utilized salicylaldehyde, ethyl isocyanoacetate, and 2-aminopyridine as the primary starting materials, along with copper(I) salts (CuI, Cu(OTf)2, etc.) as catalysts, and pyridine as a base. These chemicals served to construct molecular scaffolds that are valuable in medicinal chemistry due to their potential applications as CNS depressants, antitumor, anti-inflammatory, and antimicrobial agents, as well as their use as fluorescent markers. The study aimed to develop a straightforward and efficient approach to these molecular scaffolds, which are considered "privileged structures" in the pharmaceutical and agrochemical industries.
10.1080/00397919108020830
This study focuses on the synthesis and characterization of four novel β-cyclodextrin derivatives bearing a Schiff base moiety. The researchers aimed to create multi-functional host compounds that combine the hydrophobic binding site of β-cyclodextrin with the metal coordination site of the Schiff base moiety, potentially mimicking the activity of metalloenzymes. The new host molecules were synthesized using salicylaldehyde and various β-cyclodextrin derivatives (compounds 1, 2, 3, and 4) through a convenient method with satisfactory yields. The synthesized compounds (5, 6, 7, and 8) were characterized using 1H-NMR, FT-IR, and FAB-MS spectra, confirming the formation of the C=N bond and the disappearance of the CHO group. The study also demonstrated the formation of metal complexes, specifically with Cu(II), through FT-IR and UV-Vis spectra analysis. The results showed shifts in IR bands and the appearance of UV-Vis bands associated with d-d transitions, indicating successful coordination between the Schiff base group and Cu(II). The detailed analytical data for each compound is provided in the experimental section, highlighting the successful design and synthesis of these multi-functional host compounds.
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