scholarly journals ESI-MS Analysis of Thiol-yne Click Reaction in Petroleum Medium

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2896
Author(s):  
Evgeniya S. Degtyareva ◽  
Julia V. Burykina ◽  
Valentine P. Ananikov
Keyword(s):  
Click Reaction ◽  
Ionization Mass ◽  
Chemical Transformations ◽  
Reaction Conditions ◽  
Esi Ms ◽  
Future Developments ◽  
Low Concentrations ◽  
Vinyl Sulfides ◽  
Sustainability Concept ◽  
Heteroatomic Compounds

Petroleum contains a large number of heteroatomic compounds, but today, most of them are not efficiently utilized. The constant development of the sustainability concept recalls for rethinking the usage of fossil resources with improved chemical utility. In order to initiate research aimed at involving active petroleum compounds in chemical transformations, a new analytical method for product detection is needed. Here, we study the click reaction of thiols with alkynes, leading to the formation of α-vinyl sulfides directly in the petroleum environment. The reaction was carried out using an (IMes)Pd(acac)Cl catalyst, which demonstrated tolerance to petroleum components. In this study, the concentration of thiols ranged from 1 M to 0.01 M (from 8% to 0.1%). To detect products at low concentrations, a special alkyne labeled with an imidazole moiety was used. This approach made it possible to observe the formation of vinyl sulfides by electrospray ionization mass spectrometry (ESI-MS), which provides an opportunity for further optimization of the reaction conditions and future developments for the direct involvement of oil components in chemical reactions.

Possible intermediates of Cu(phen)-catalyzed C–O cross-coupling of phenol with an aryl bromide by in situ ESI-MS and EPR studies

2014 ◽  
Vol 43 (29) ◽  
pp. 11410-11417 ◽  
Author(s):  
Hong-Jie Chen ◽  
I-Jui Hsu ◽  
Mei-Chun Tseng ◽  
Shin-Guang Shyu
Keyword(s):  
Mass Spectrometry ◽  
Electrospray Ionization ◽  
Catalytic Reaction ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Ionization Mass ◽  
Aryl Bromide ◽  
Reaction Conditions ◽  
Esi Ms

Cu(phen) complexes were observed in the copper(i)-catalyzed C–O coupling reaction using K2CO3 as the base and phen as the ligand under the catalytic reaction conditions by in situ electrospray ionization mass spectrometry (ESI-MS) and EPR analysis.

scholarly journals A highly sensitive octopus-like azobenzene fluorescent probe for determination of abamectin B1 in apples

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhenlong Guo ◽  
YiFei Su ◽  
Kexin Li ◽  
MengYi Tang ◽  
Qiang Li ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Ionization Mass ◽  
Limit Of Quantification ◽  
Visible Absorption ◽  
Esi Ms ◽  
Relative Standard ◽  
Ft Ir

AbstractThe development of detecting residual level of abamectin B1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5′-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B1 in apples. The TPB molecule has been characterized by ultraviolet–visible absorption spectrometry, 1H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectra. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L−1 and 4.4 μg L−1, respectively. The mechanism of this probe to identify abamectin B1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B1 in apples was achieved. Good reproducibility was present based on relative standard deviation of 2.2%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B1 of this fluorescent probe demonstrated reasonable sensitivity, specificity and selectivity. The results indicate that the octopus-like azobenzene fluorescent probe can be expected to be reliable for evaluating abamectin B1 in agricultural foods.

A Dynamic Substrate is Required for MhuD-catalyzed Degradation of Heme to Mycobilin

2021 ◽  
Author(s):  
Biswash Thakuri ◽  
Bruce O'Rourke ◽  
Amanda Graves ◽  
Matthew Liptak
Keyword(s):  
Dynamic Equilibrium ◽  
Ionization Mass ◽  
Esi Ms ◽  
Enzymatic Mechanism ◽  
Single Turnover ◽  
Rate Limiting Step ◽  
Planar Substrate ◽  
Out Of Plane ◽  
Substrate Conformation ◽  
Rate Limiting

The non-canoncial heme oxygenase MhuD from <i>Mycobacterium tuberculosis</i> binds a heme substrate that adopts a dynamic equilibrium between planar and out-of-plane ruffled conformations. MhuD degrades this substrate to an unusual mycobilin product via successive monooxygenation and dioxygenation reactions. This article establishes a causal relationship between heme substrate dynamics and MhuD-catalyzed heme degradation resulting in a refined enzymatic mechanism. UV/Vis absorption (Abs) and electrospray ionization mass spectrometry (ESI-MS) data demonstrated that a second-sphere substitution favoring population of the ruffled heme conformation changed the rate-limiting step of the reaction resulting in a measurable build-up of the monooxygenated meso-hydroxyheme intermediate. In addition, UV/Vis Abs and ESI-MS data for a second-sphere variant that favored the planar substrate conformation showed that this change altered the enzymatic mechanism resulting in an alpha-biliverdin product. Single-turnover kinetic analyses for three MhuD variants revealed that the rate of heme monooxygenation depends upon the population of the ruffled substrate conformation. These kinetic analyses also revealed that the rate of meso-hydroxyheme dioxygenation by MhuD depends upon the population of the planar substrate conformation. Thus, the ruffled haem conformation supports rapid heme monooxygenation by MhuD, but further oxygenation to the mycobilin product is inhibited. In contrast, the planar substrate conformation exhibits altered heme monooxygenation regiospecificity followed by rapid oxygenation of meso-hydroxyheme. Altogether, these data yielded a refined enzymatic mechanism for MhuD where access to both substrate conformations is needed for rapid incorporation of three oxygen atoms into heme yielding mycobilin.<br>

scholarly journals New Bis-Alkenoic Acid Derivatives from a Marine-Derived Fungus Fusarium solani H915

Marine Drugs ◽  
2018 ◽  
Vol 16 (12) ◽  
pp. 483 ◽  
Author(s):  
Shun-Zhi Liu ◽  
Xia Yan ◽  
Xi-Xiang Tang ◽  
Jin-Guo Lin ◽  
Ying-Kun Qiu
Keyword(s):  
Fusarium Solani ◽  
Zebrafish Embryo ◽  
Pathogenic Fungi ◽  
Fungal Species ◽  
Ionization Mass ◽  
Alkenoic Acid ◽  
Low Concentrations ◽  
Significant Toxicity ◽  
New Compounds ◽  
Acid Esters

Fusarium solani H915 is a fungus derived from mangrove sediments. From its ethyl acetate extract, a new alkenoic acid, fusaridioic acid A (1), three new bis-alkenoic acid esters, namely, fusariumester A1 (2), A2 (3) and B (4), together with three known compounds (5–7), were isolated. The structures of the new compounds were comprehensively characterized by high resolution electrospray ionization-mass spectrometry (HR-ESI-MS), 1D and 2D nuclear magnetic resonance (NMR). Additionally, the antifungal activities against tea pathogenic fungi Pestalotiopsis theae and Colletotrichum gloeosporioides were studied. The new compound, 4, containing a β-lactone ring, exhibited moderate inhibitory activity against P. theae, with an MIC of 50 μg/disc. Hymeglusin (6), a typical β-lactone antibiotic and a terpenoid alkaloid, equisetin (7), exhibited potent inhibitory activities against both fungal species. The isolated compounds were evaluated for their effects on zebrafish embryo development. Equisetin clearly imparted toxic effect on zebrafish even at low concentrations. However, none of the alkenoic acid derivatives exhibited significant toxicity to zebrafish eggs, embryos, or larvae. Thus, the β-lactone containing alkenoic acid derivatives from F. solani H915 are low in toxicity and are potent antifungal agents against tea pathogenic fungi.

scholarly journals A Flexible Synthesis of 68Ga-Labeled Carbonic Anhydrase IX (CAIX)-Targeted Molecules via CBT/1,2-Aminothiol Click Reaction

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 23 ◽  
Author(s):  
Kuo-Ting Chen ◽  
Kevin Nguyen ◽  
Christian Ieritano ◽  
Feng Gao ◽  
Yann Seimbille
Keyword(s):  
Carbonic Anhydrase ◽  
Half Life ◽  
Reaction Rate ◽  
Click Reaction ◽  
Tumor Hypoxia ◽  
Carbonic Anhydrase Ix ◽  
Reaction Conditions ◽  
Positron Emitter ◽  
Radiochemical Yields ◽  
Gallium 68

We herein describe a flexible synthesis of a small library of 68Ga-labeled CAIX-targeted molecules via an orthogonal 2-cyanobenzothiazole (CBT)/1,2-aminothiol click reaction. Three novel CBT-functionalized chelators (1–3) were successfully synthesized and labeled with the positron emitter gallium-68. Cross-ligation between the pre-labeled bifunctional chelators (BFCs) and the 1,2-aminothiol-acetazolamide derivatives (8 and 9) yielded six new 68Ga-labeled CAIX ligands with high radiochemical yields. The click reaction conditions were optimized to improve the reaction rate for applications with short half-life radionuclides. Overall, our methodology allows for a simple and efficient radiosynthetic route to produce a variety of 68Ga-labeled imaging agents for tumor hypoxia.

scholarly journals Analysis of Inositol Phosphate Metabolism by Capillary Electrophoresis Electrospray Ionization Mass Spectrometry (CE-ESI-MS)

2020 ◽  
Author(s):  
Danye Qiu ◽  
Miranda S. Wilson ◽  
Verena B. Eisenbeis ◽  
Robert K. Harmel ◽  
Esther Riemer ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Capillary Electrophoresis ◽  
Electrospray Ionization ◽  
Electrospray Ionization Mass Spectrometry ◽  
Inositol Phosphate ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Phosphate Metabolism ◽  
Esi Ms ◽  
Inositol Phosphate Metabolism

AbstractThe analysis of myo-inositol phosphates (InsPs) and myo-inositol pyrophosphates (PP-InsPs) is a daunting challenge due to the large number of possible isomers, the absence of a chromophore, the high charge density, the low abundance, and the instability of the esters and anhydrides. Given their importance in biology, an analytical approach to follow and understand this complex signaling hub is highly desirable. Here, capillary electrophoresis (CE) coupled to electrospray ionization mass spectrometry (ESI-MS) is implemented to analyze complex mixtures of InsPs and PP-InsPs with high sensitivity. Stable isotope labeled (SIL) internal standards allow for matrix-independent quantitative assignment. The method is validated in wild-type and knockout mammalian cell lines and in model organisms. SIL-CE-ESI-MS enables for the first time the accurate monitoring of InsPs and PP-InsPs arising from compartmentalized cellular synthesis pathways, by feeding cells with either [13C6]-myo-inositol or [13C6]-D-glucose. In doing so, we uncover that there must be unknown inositol synthesis pathways in mammals, highlighting the unique potential of this method to dissect inositol phosphate metabolism and signalling.

scholarly journals SYNTHESIS OF AN AZIDE–THIOL LINKER FOR HETEROGENEOUS POLYMER FUNCTIONALIZATION VIA THE “CLICK” REACTION

2018 ◽  
Vol 55 (1B) ◽  
pp. 152
Author(s):  
Thuy Thu Truong
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Click Reaction ◽  
Proton Nuclear Magnetic Resonance ◽  
Reaction Yield ◽  
Reaction Conditions ◽  
Click Reactions ◽  
Heterogeneous Polymer ◽  
Ft Ir ◽  
First Time ◽  
Layer Chromatography

In this study, the synthesis of a telechelic linker bearing both azide and thiol functional groups was described. The reaction conditions were investigated to optimize the reaction yield. The product was analyzed using thin layer chromatography (TLC) and proton nuclear magnetic resonance (1H NMR). The employment of the obtained azide–thiol linker in heterogeneous polymer “click” functionalization was demonstrated for the first time, which was monitored by an online FT–IR method. The obtained telechelic azide–thiol linker is envisioned to be useful chemical tools to link macromolecular chains via orthogonal click reactions.

scholarly journals The Peculiar Case of the Hyperthermostable Pyrimidine Nucleoside Phosphorylase from Thermus Thermophilus

2020 ◽  
Author(s):  
Felix Kaspar ◽  
Peter Neubauer ◽  
Anke Kurreck
Keyword(s):  
Thermus Thermophilus ◽  
Pyrimidine Nucleoside ◽  
Reaction Conditions ◽  
Nucleoside Phosphorylase ◽  
Pyrimidine Nucleosides ◽  
Low Concentrations ◽  
Pyrimidine Nucleoside Phosphorylase ◽  
Total Turnover ◽  
Nucleoside Phosphorylases ◽  
Peculiar Case

The poor solubility of many nucleoside and nucleobases in aqueous solution demands harsh reaction conditions (base, heat, cosolvent) in nucleoside phosphorylase-catalyzed processes to facilitate substrate loading beyond the low millimolar range. This, in turn, requires enzymes which withstand these conditions. Herein we report that the pyrimidine nucleoside phosphorylase from <i>Thermus thermophilus</i> is active over an exceptionally broad pH (4-10), temperature (up to 100 °C) and cosolvent space (up to 80% (v/v) non-aqueous medium) and displays tremendous stability under harsh reaction conditions with predicted total turnover numbers of more than 10<sup>6</sup> for various pyrimidine nucleosides. However, its use as a biocatalyst for preparative applications is critically limited due to its inhibition by nucleoside substrates at low concentrations, which is unprecedented among non-specific pyrimidine nucleoside phosphorylases.<br>

Ligand free copper(i)-catalyzed synthesis of diaryl ether with Cs2CO3via a free radical path

2015 ◽  
Vol 44 (27) ◽  
pp. 12086-12090 ◽  
Author(s):  
Hong-Jie Chen ◽  
Mei-Chun Tseng ◽  
I-Jui Hsu ◽  
Wei-Ting Chen ◽  
Chien-Chung Han ◽  
...  
Keyword(s):  
Free Radical ◽  
Catalytic Reaction ◽  
Coupling Reaction ◽  
Reaction Conditions ◽  
Esi Ms ◽  
Ms Analysis ◽  
Diaryl Ether ◽  
Ligand Free

Complexes [Cu(i)(2,4-dimethylphenoxy)2]− (A) and [Cu(ii)(2,4-dimethylphenoxy)2(p-tolyl)]− (B) were observed by in situ ESI-MS analysis of the ligand free copper(i)-catalyzed C–O coupling reaction using Cs2CO3 under the catalytic reaction conditions.

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