10.1016/j.cclet.2013.11.024
The research presented in the scholarly article focuses on the development of a highly selective two-photon fluorescent probe, ADNO (2-(α-(3,4-diaminophenoxy)acetyl)-6(dimethylamino)naphthalene), for imaging nitric oxide (NO) in living cells. The probe is designed based on the photoinduced electron transfer (PET) mechanism, utilizing o-phenylenediamine as the NO-sensitive fluorescence modulator and 2-acetyl-6-(dimethylamino)naphthalene (Acedan) as the two-photon fluorophore. The detection of NO is achieved by monitoring the alteration of electron-donating capacity of the o-phenylenediamine moiety, which quenches the fluorescence of Acedan but is reversed in the presence of NO due to the transformation into benzotriazole, thus reviving fluorescence. The probe's rapid response, remarkable fluorescent enhancement, and excellent chemoselectivity for NO over other reactive oxygen/nitrogen species (ROS/RNS) and common metal ions were demonstrated through a series of experiments. These experiments included the synthesis of ADNO, its spectral characterization, and its application in fluorescence imaging of NO in living cells using both one-photon microscopy (OPM) and two-photon microscopy (TPM). The study also assessed the probe's performance at various pH levels and its stability and selectivity in the presence of different ROS/RNS and metal ions. The research utilized various analytical techniques such as NMR, mass spectrometry, UV–vis, and fluorescence spectroscopy to characterize the probe and evaluate its performance.
10.14233/ajchem.2015.17567
The research primarily focuses on the synthesis and structural characterization of four novel 2-(hydroxyethoxy substituted)phenyl benzimidazoles, which are derivatives of benzimidazole known for their various biological and physiological activities. The study employs two distinct synthetic routes to produce these compounds, starting from commercially purchased materials without further purification. Route I involves the reaction of hydroxyl substituted benzaldehyde with o-phenylendiamine to form intermediates, which are then subjected to an o-hydroxyethylation reaction with chlorohydrin to yield the final products. This route is applicable for compounds where the hydroxyethoxy group is in the para- or meta-position relative to the benzimidazole in the benzene ring. Route II, used for ortho-substituted phenyl benzimidazole due to steric hindrance, synthesizes hydroxyethoxy substituted benzaldehyde first, which then reacts with o-phenylendiamine. The synthesized compounds were characterized using various analytical techniques including melting point determination, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and elemental analysis. Single-crystal X-ray diffraction analysis was also conducted to confirm the structures and provide insights into the stereochemistry of the molecules.
10.1016/j.tetlet.2008.11.123
The research focuses on the development of a novel three-component reaction for the synthesis of N-cyclohexyl-3-aryl-quinoxaline-2-amines, which are nitrogen-containing heterocyclic compounds with significant biological activity and applications in drug discovery and various chemical industries. The study utilizes a three-component condensation reaction catalyzed by ferric perchlorate, involving o-phenylenediamine, aromatic aldehydes, and cyclohexyl isocyanide, to produce the desired quinoxaline derivatives in good yields. The experiments were conducted by refluxing a mixture of the three reactants in acetonitrile with a catalytic amount of ferric perchlorate for 2 hours. The progress of the reactions was monitored by thin-layer chromatography (TLC), and the products were obtained without further purification after the reaction mixture was diluted, separated, and dried. The synthesized compounds were characterized using melting point determination, infrared spectroscopy (IR), proton and carbon nuclear magnetic resonance (1H NMR and 13C NMR), gas chromatography-mass spectrometry (GC/MS), and elemental analysis, which confirmed their structures and composition.
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.
10.1007/s10847-010-9878-1
The research focuses on the synthesis and metal ion complexation of acyclic Schiff base podands with lipophilic amide and ester end groups. The purpose of this study was to create a series of acyclic Schiff base podands (14–19) and investigate their ability to form complexes with transition metal ions, with the aim of enhancing complexing abilities and selectivity towards various metal ions. The researchers used conductometric methods in acetonitrile at 25°C to study the complexation, and they found that Schiff base podands 14–16 formed stable 1:1 complexes with Hg2+, Pb2+, Cu2+, Zn2+, and Cd2+, indicating a continuous decrease in molar conductances at a 1:1 mole ratio of crown-to-metal. The stability constants followed the order: Hg2+ > Pb2+ > Cu2+ > Zn2+ > Cd2+ > Ag+. The chemicals used in the synthesis process included ethylenediamine or 1,2-diaminobenzenes, aldehydes, and various metal salts such as AgNO3, Cu(ClO4)2·6H2O, Pb(ClO4)2·3H2O, Zn(ClO4)2·6H2O, Cd(ClO4)2, and Hg(ClO4)2·xH2O. The conclusions of the research were that the newly synthesized acyclic Schiff base ligands demonstrated good complexation ability for certain metal cations but showed low selectivity. Anomalous behavior was observed in the complexation of Hg2+, Cu2+, and Zn2+ ions with Schiff base ligands 18 and 19.
10.1080/00397910902985465
The research focuses on the facile and simple synthesis of novel 1-methyl-2-(2-substituted-oxazol-4-yl)-1H-benzimidazole derivatives, which are heterocyclic compounds with significant biological activity. The synthesis process involves the condensation of o-phenylenediamine with lactic acid to yield 2-(a-hydroxyethyl)benzimidazole, followed by oxidation to produce 2-acetyl benzimidazole. This compound undergoes N-methylation and bromination to form an intermediate, which is then converted into its ester form by reacting with various carboxylic acids in an acetone medium. The key step involves treating these esters with acetamide in the presence of BF3-etherate, a Lewis acid, to obtain the desired oxazole derivatives. The experiments utilized various analytical techniques, including 1H and 13C NMR, IR spectroscopy, mass spectrometry, and thin-layer chromatography (TLC), to monitor the progress of the reactions and characterize the synthesized compounds. The study successfully developed a facile synthetic process for the target benzimidazole derivatives and proposed a plausible mechanism for the conversion of esters to the corresponding oxazoles.
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