Month: December 2022

Chesnokova, Alexandra N. published the artcileSynthesis and properties of composite membranes for polymer electrolyte membrane fuel cells, Application In Synthesis of 636-73-7, the publication is Advanced Materials Research (Durnten-Zurich, Switzerland) (2014), 251-256, database is CAplus.

The paper is devoted to the sol-gel synthesis of proton conductive organic-silicon composite membranes based on tetra-Et orthosilicate (TEOS) and copolymers of 2-methyl-5-vinylpyridine and vinyl chloride (MVP-VC), 2-methyl-5-vinylpyridine and vinyl acetate (MVP-VA), copolymers of ethylene glycol vinyl glycidyl ether and styrene (KS-1 and KS-2), and nitrogen-containing heteroaromatic derivatives of sulfonic acids: 2-phenyl-5-benzimidazolsulfonic acid (PBISA) and pyridine-3-sulfonic acid (PSA). Properties of synthesized membranes, such as proton conductivity, activation energy, ion exchange capacity, dimensional stability have been investigated.

Advanced Materials Research (Durnten-Zurich, Switzerland) published new progress about 636-73-7. 636-73-7 belongs to pyridine-derivatives, auxiliary class Pyridine,Sulfonic acid, name is Pyridine-3-sulfonic acid, and the molecular formula is C5H5NO3S, Application In Synthesis of 636-73-7.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Cox, Paul A. published the artcileProtodeboronation of Heteroaromatic, Vinyl, and Cyclopropyl Boronic Acids: pH-Rate Profiles, Autocatalysis, and Disproportionation, Name: 2-Pyridinylboronic acid, the publication is Journal of the American Chemical Society (2016), 138(29), 9145-9157, database is CAplus and MEDLINE.

PH-rate profiles for aqueous-organic protodeboronation of 18 boronic acids, many widely viewed as unstable, have been studied by NMR and DFT. Rates were pH-dependent, and varied substantially between the boronic acids, with rate maxima that varied over 6 orders of magnitude. A mechanistic model containing five general pathways (k₁-k₅) has been developed, and together with input of [B]_tot, K_W, K_a, and K_aH, the protodeboronation kinetics can be correlated as a function of pH (1-13) for all 18 species. Cyclopropyl and vinyl boronic acids undergo very slow protodeboronation, as do 3- and 4-pyridyl boronic acids (t_0.5 > 1 wk, pH 12, 70 °C). In contrast, 2-pyridyl and 5-thiazolyl boronic acids undergo rapid protodeboronation (t_0.5 â‰?25-50 s, pH 7, 70 °C), via fragmentation of zwitterionic intermediates. Lewis acid additives (e.g., Cu, Zn salts) can attenuate (2-pyridyl) or accelerate (5-thiazolyl and 5-pyrazolyl) fragmentation. Two addnl. processes compete when the boronic acid and the boronate are present in sufficient proportions (pH = pK_a ± 1.6): (i) self-/autocatalysis and (ii) sequential disproportionations of boronic acid to borinic acid and borane.

Journal of the American Chemical Society published new progress about 197958-29-5. 197958-29-5 belongs to pyridine-derivatives, auxiliary class Pyridine,Boronic acid and ester, name is 2-Pyridinylboronic acid, and the molecular formula is C5H6BNO2, Name: 2-Pyridinylboronic acid.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Kerric, Gaelle published the artcileUse of polymer-supported phenyltin for the creation of aryl-aryl or aryl-heteroaryl bonds via Stille cross-coupling reactions, Synthetic Route of 89076-64-2, the publication is Journal of Organometallic Chemistry (2009), 695(1), 103-110, database is CAplus.

An insoluble polymer-supported phenyltin reagent was successfully used in Stille cross-coupling reactions with aryl- and heteroaryl halides. Cross-coupling products were isolated in good to high yields with very low contamination by tin and palladium residues after removal of the residual supported organotin halide. The regeneration and recyclability of the supported phenyltin reagent were also examined and proved to be possible, but required palladium cleaning of the grafted polymer to be efficient along 4 cycles when Pd(PPh₃)₄ was used as catalyst.

Journal of Organometallic Chemistry published new progress about 89076-64-2. 89076-64-2 belongs to pyridine-derivatives, auxiliary class Pyridine,Nitro Compound,Benzene, name is 5-Nitro-2-phenylpyridine, and the molecular formula is C11H8N2O2, Synthetic Route of 89076-64-2.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Fenger, Isabelle published the artcileReusable polymer-supported palladium catalysts: an alternative to tetrakis(triphenylphosphine)palladium in the Suzuki cross-coupling reaction, Recommanded Product: 5-Nitro-2-phenylpyridine, the publication is Tetrahedron Letters (1998), 39(24), 4287-4290, database is CAplus.

The Suzuki cross-coupling reaction of a boronic acid and a bromoarom. compound requires palladium catalysis. Almost identical yields were obtained under the usual conditions, with 30 mequivalent of Pd(PPh₃)₄, and with 2 mequiv of a polymer-supported catalyst, which was easily prepared in two steps from Merrifield polymer. Recovery and reuse of the catalyst is easy, and only 0.60% of the initial amount of palladium is lost during a reaction.

Tetrahedron Letters published new progress about 89076-64-2. 89076-64-2 belongs to pyridine-derivatives, auxiliary class Pyridine,Nitro Compound,Benzene, name is 5-Nitro-2-phenylpyridine, and the molecular formula is C11H8N2O2, Recommanded Product: 5-Nitro-2-phenylpyridine.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Gragg, B. R. published the artcileA carbon-13 NMR study on some phenylborane derivatives, SDS of cas: 971-66-4, the publication is Journal of Organometallic Chemistry (1977), 132(1), 29-36, database is CAplus.

The intensity of 13C NMR signals of C atoms bonded to B can frequently be increased by recording the spectra at low temperatures Though this procedure results in a loss of fine structure, it enables the determination of chem. shift data for NMR signals that are either broad or unobservable at ambient temperature High temperature recording of spectra seems to be a useful technique for resolving multiplet resonance signals that are collapsed in ambient temperature spectra. 13C NMR data are reported for a variety of phenylborane derivatives; no simple correlation seems to exist between δ13C of the phenyl C atom bonded to B and δ11B of the phenylborane species.

Journal of Organometallic Chemistry published new progress about 971-66-4. 971-66-4 belongs to pyridine-derivatives, auxiliary class Pyridine,Benzene, name is Triphenyl(pyridin-1-ium-1-yl)borate, and the molecular formula is C23H20BN, SDS of cas: 971-66-4.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Ulivieri, Alessandra published the artcileThyroid hormones regulate cardiac repolarization and QT-interval related gene expression in hiPSC cardiomyocytes, Name: Dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate, the publication is Scientific Reports (2022), 12(1), 568, database is CAplus and MEDLINE.

Prolongation of cardiac repolarization (QT interval) represents a dangerous and potentially life-threatening elec. event affecting the heart. Thyroid hormones (THs) are critical for cardiac development and heart function. However, little is known about THs influence on ventricular repolarization and controversial effects on QT prolongation are reported. Human iPSC-derived cardiomyocytes (hiPSC-CMs) and multielectrode array (MEA) systems were used to investigate the influence of 3,3′,5-triiodo-L-Thyronine (T3) and 3,3′,5,5′-tetraiodo-L-Thyronine (T4) on corrected Field Potential Duration (FPDc), the in vitro analog of QT interval, and on local extracellular Action Potential Duration (APD). Treatment with high THs doses induces a significant prolongation of both FPDc and APD, with the strongest increase reached after 24 h exposure. Preincubation with reverse T3 (rT3), a specific antagonist for nuclear TH receptor binding, significantly reduces T3 effects on FPDc, suggesting a TRs-mediated transcriptional mechanism. RNA-seq anal. showed significant deregulation in genes involved in cardiac repolarization pathways, including several QT-interval related genes. In conclusion, long-time administration of high THs doses induces FPDc prolongation in hiPSC-CMs probably through the modulation of genes linked to QT-interval regulation. These results open the way to investigate new potential diagnostic biomarkers and specific targeted therapies for cardiac repolarization dysfunctions.

Scientific Reports published new progress about 21829-25-4. 21829-25-4 belongs to pyridine-derivatives, auxiliary class Membrane Transporter/Ion Channel,Calcium Channel, name is Dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate, and the molecular formula is C9H5Cl2F3, Name: Dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Motornov, Vladimir published the artcileCopper(I)-Catalyzed Regioselective Chan-Lam N2-Vinylation of 1,2,3-Triazoles and Tetrazoles, Name: (1-(tert-Butoxycarbonyl)-1,2,3,6-tetrahydropyridin-4-yl)boronic acid, the publication is Advanced Synthesis & Catalysis (2019), 361(14), 3306-3311, database is CAplus.

Copper-catalyzed coupling of π-deficient NH-azoles with vinylboronic acids or vinyltrifluoroborate salt provided a direct route to N2-vinyl-1,2,3-triazoles and N2-vinyltetrazoles. The coupling reaction was efficiently catalyzed by (phen)Cu(PPh₃)Br with low catalyst loading (5 mol%) under base-free conditions. The method was applicable for vinylation of unsubstituted, monosubstituted and disubstituted 1,2,3-triazoles with various functionalities with high N2-selectivity.

Advanced Synthesis & Catalysis published new progress about 844501-00-4. 844501-00-4 belongs to pyridine-derivatives, auxiliary class Pyridine,Boronic acid and ester,Amide,Boronic Acids,Boronic acid and ester, name is (1-(tert-Butoxycarbonyl)-1,2,3,6-tetrahydropyridin-4-yl)boronic acid, and the molecular formula is C10H18BNO4, Name: (1-(tert-Butoxycarbonyl)-1,2,3,6-tetrahydropyridin-4-yl)boronic acid.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Montes, Rafael published the artcileCoupling of redox and complex formation processes for the kinetic determination of palladium, Safety of 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, the publication is Analyst (Cambridge, United Kingdom) (1985), 110(11), 1339-41, database is CAplus.

A kinetic-spectrophotometric procedure for the determination of μg amounts of Pd(II) with pyridine-2-aldehyde 2-pyridylhydrazone (I) is described. The bromate oxidation of the dye is followed at 372 nm. The method is based on the decrease in the reaction rate produced by Pd complexation of I. A relative standard deviation of 2.5% was obtained in the range 0.5-3.2 μg/mL of Pd. Factors influencing the sensitivity and interferences from model solutions are discussed.

Analyst (Cambridge, United Kingdom) published new progress about 2215-33-0. 2215-33-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, and the molecular formula is C11H10N4, Safety of 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Montes, R. published the artcileKinetic determination of nitrite in drinking water by fluorometry, Application of 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, the publication is Analytical Sciences (1991), 7(3), 467-71, database is CAplus.

A method for the kinetic determination of nanogram amounts of NO₂^– is based on its acceleration of the rate of bromination of pyridine-2-aldehyde 2-pyridylhydrazone in acidic medium. The reaction is followed by fluorometry while monitoring the formation of a fluorescent product using an excitation wavelength of 291 nm and an emission wavelength of 432 nm. The method was applied to drinking water anal., with a detection limit of 4.6 ng/mL and recoveries 92-105%. The relative standard deviation of the method is 2.4%. The major advantages of this method are simplicity, absence of a reagent blank, selectivity, and sensitivity.

Analytical Sciences published new progress about 2215-33-0. 2215-33-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, and the molecular formula is C11H10N4, Application of 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Montes, R. published the artcileSpectrophotometric reaction-rate method for the determination of nitrite in waters with pyridine-2-aldehyde 2-pyridylhydrazone, Recommanded Product: 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, the publication is Talanta (1987), 34(12), 1021-6, database is CAplus and MEDLINE.

A method for the kinetic determination of submicrogram amounts of NO₂^– was developed, based on the bromate oxidation of pyridine-2-aldehyde 2-pyridylhydrazone in an acidic medium by NO₂^–. The reaction is monitored spectrophotometrically at 372 nm. A comparative study with HCl and HClO₄ media shows that the anal. parameters are affected by the type of acid used. Within-day precision, based on 10 replicate determinations, was >0.011 μg/mL, which corresponds to 2.2-1.5% relative standard deviation at the concentrations examined Application of this method in the determination of NO₂^– in water is discussed. The recovery of NO₂^– from drinking waters was 90-117%, and the average relative standard deviation for NO₂^– determination is polluted river water was 3.2%. Large amounts of NO₂^– and NH₄⁺ do not interfere. However, there is interference by Cu²⁺, Pd²⁺, and electroactive substances. Major advantages for the method are simplicity, absence of a reagent blank, and the wide determination range.

Talanta published new progress about 2215-33-0. 2215-33-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, and the molecular formula is C11H10N4, Recommanded Product: 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem