Month: October 2022

Schubert, Steffen; Bauer, Andrea; Hillen, Uwe; Werfel, Thomas; Geier, Johannes; Brans, Richard; IVDK published the artcile< Occupational contact dermatitis in painters and varnishers: Data from the Information Network of Departments of Dermatology ( IVDK ), 2000 to 2019>, Category: pyridine-derivatives, the main research area is occupational contact dermatitis paints varnish human; allergic contact dermatitis; epoxy resin; face dermatitis; methylchloroisothiazolinone; methylisothiazolinone; occupational dermatitis; painter; patch test; varnisher.

Painters and varnishers (“”painters””) are exposed to various contact allergens and skin irritants, and therefore, are at risk for developing occupational dermatitis (OD). To describe the spectrum of occupational sensitizations in painters and revise the corresponding current patch test recommendations. Retrospective anal. of Information Network of Departments of Dermatol. (IVDK) data from 2000 to 2019 with focus on male painters with OD, ages 20-59 years (n = 557) in comparison to age-matched male painters without OD (n = 422) and male OD patients who have had never worked as painters (n = 13 862). Male painters with OD have a significantly higher rate of allergic contact dermatitis and face dermatitis than male patients with OD who work in other professions. Pos. patch tests to epoxy resin, methylisothiazolinone (MI), and methylchloroisothiazolinone (MCI)/MI were significantly more frequent in painters with OD than in the other groups. Epoxy resin sensitization was significantly associated with face dermatitis. Epoxy resin, MI, and MCI/MI represent the most important occupational sensitizers in painters. In addition to baseline, resins and glues, and industrial biocides series, the patients′ own workplace materials should be tested in painters with suspected OD.

Contact Dermatitis published new progress about Alcohols, C16-18, ethoxylated Role: ADV (Adverse Effect, Including Toxicity), BIOL (Biological Study). 3811-73-2 belongs to class pyridine-derivatives, and the molecular formula is C5H4NNaOS, Category: pyridine-derivatives.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Kasting, Gerald B.; Miller, Matthew A.; Xu, Lijing; Yu, Fang; Jaworska, Joanna published the artcile< In Vitro Human Skin Absorption of Solvent-deposited Solids: Niacinamide and Methyl Nicotinate>, Application of C7H7NO2, the main research area is niacinamide methyl nicotinate skin absorption; Absorption; Disposition; Passive diffusion/transport; Percutaneous; Permeability; Skin; Transdermal; pathways.

A quant. understanding of the dose dependence of topical delivery is important to cosmetic and dermatol. product development and to risk assessment for hazardous chems. contacting the skin. Despite considerable research, predictive capability in this area remains limited. To this end we conducted an exptl. skin absorption study of two closely related skin care agents, niacinamide (nicotinamide, NA) and Me nicotinate (MN), and analyzed the results quant. using a transient diffusion model described sep. (Yu et al. submitted for publication). Radiolabeled test compounds were solvent-deposited onto ex vivo human skin mounted in Franz diffusion cells over a dose range exceeding 4.5 orders of magnitude, and permeation was measured over a 1-4 day period. At low doses, the permeation rate of NA was approx. 60-fold lower than that of its lower melting, more lipophilic analog, MN; at high doses an even greater difference was observed The difference can be qual. explained based on higher lipid solubility and lower crystallinity of MN relative to NA. Dissolution-limited mass transfer through a lipid layer at the SC surface is suggested. Relevance of the results to practical skin care formulations was confirmed by a parallel study of NA in an o/w emulsion.

Journal of Pharmaceutical Sciences (Philadelphia, PA, United States) published new progress about Crystallinity. 93-60-7 belongs to class pyridine-derivatives, and the molecular formula is C7H7NO2, Application of C7H7NO2.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Vezzu, Keti; Nawn, Graeme; Pagot, Gioele; Negro, Enrico; Nale, Angeloclaudio; Bang, Yannick Herve; Conti, Fosca; Cavinato, Gianni; Di Noto, Vito published the artcile< Relaxation phenomena and conductivity mechanisms in anion-exchange membranes derived from polyketone>, Safety of Pyridin-4-ylmethanamine, the main research area is relaxation conductivity anion exchange membrane polyketone.

A polyketone-b-poly[N-(4 Me-methylpyridium)-ethylenepyrrole+][X-], with X- = I- or OH-, was studied as an example of anion-exchange membrane with potential applications in fuel cells. The polyketone starting material PK and the functionalized polyketones Pyr-FPKmI and Pyr-FPKmOH were studied via Broadband Elec. Spectroscopy (BES) to understand the conductivity mechanism. BES signals are collected in the frequency range of 10-2 – 107 Hz and from -100° to 120°. BES measurements reveal up to three interdomain polarizations phenomena, one electrode polarization event and two β dielec. relaxation modes for both wet Pyr-FPKmI and Pyr-FPKmOH. Ion conductivity for Pyr-FPKmI and Pyr-FPKmOH is 0.0086 and 0.0105 S cm-1 at 80°, resp. The overall conductivity mechanism is attributed to the superposition of two conduction pathways, via delocalization bodies and via interdomain percolation pathways, which are associated with two different phys. phenomena.

Electrochimica Acta published new progress about Anion exchange membranes. 3731-53-1 belongs to class pyridine-derivatives, and the molecular formula is C6H8N2, Safety of Pyridin-4-ylmethanamine.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Kehner, Rebecca A.; Hewitt, Matthew Christian; Bayeh-Romero, Liela published the artcile< Expanding Zirconocene Hydride Catalysis: In Situ Generation and Turnover of ZrH Catalysts Enabling Catalytic Carbonyl Reductions>, Electric Literature of 350-03-8, the main research area is zirconium hydride in situ preparation zirconocene dichloride hydrosilane; ketone aldehyde enone ynone lactone reduction zirconium hydride catalyst.

Despite the wide use and popularity of metal hydride catalysis, methods utilizing zirconium hydride catalysts remain underexplored. Here, authors report the development of a mild method for the in situ prepatation. and use of zirconium hydride catalysts. This robust method requires only 2.5-5 mol % of zirconocene dichloride in combination with a hydrosilane as the stoichiometric reductant and does not necessitate careful air- or moisture-free technique. A key finding of this study concerns an amine-mediated ligand exchange en route to the active zirconocene hydride catalyst. Mechanistic investigation supports the intermediacy of an oxo-bridged dimer precatalyst. The application of this method to the reduction of a wide variety of carbonyl-containing substrates, including ketones, aldehydes, enones, ynones, and lactones is demonstrated with up to 92% yield and exhibiting broad functional group tolerability. These findings open up alternative avenues for the catalytic application of chlorozirconocenes, potentially serving as the foundation for broader applications of zirconium hydride catalysis.

ACS Catalysis published new progress about Alcohols Role: SPN (Synthetic Preparation), PREP (Preparation). 350-03-8 belongs to class pyridine-derivatives, and the molecular formula is C7H7NO, Electric Literature of 350-03-8.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Kamga, Justin; Leonte, Denisa; Ambassa, Pantaleon; Mbaveng, Armelle T.; Fotso, Ghislain W.; Coman, Fana-Maria; Ngadjui, Bonaventure T.; Kuete, Victor; Zaharia, Valentin; Ngameni, Bathelemy published the artcile< Heterocycles 45.Synthesis, characterization and biological evaluation of 3-indolyl-1-pyridyl-2-propenones as anticancer agents>, Reference of 350-03-8, the main research area is acetylpyridine indolyl carbaldehyde diastereoselective Claisen Schmidt condensation; indolyl pyridyl propenone preparation antitumor cytotoxicity.

A series of seven indolyl pyridyl propenones I [R = H, Me, Et, etc.; Ar = 3-pyridyl, 4-pyridyl] were synthesized via Claisen-Schmidt condensation with 68.8-91.8% yields. All the synthesized compounds I were purified and characterized by m.ps., IR, 1H NMR, 13C NMR and HRMS. The cytotoxicity of the synthesized indolyl pyridyl propenones I and doxorubicin, used as pos. control, was determined in a panel of nine human cancer cell lines including both sensitive and drug-resistant phenotypes, as well as in normal AML12 hepatocytes. Compounds I [R = Et, allyl; Ar = 4-pyridyl] and [R = Me; Ar = 3-pyridyl] displayed half maximal inhibitory concentration (IC50) values below 100μM in all tested cancer cell lines meanwhile, other compounds displayed selective activities.

Farmacia (Bucharest, Romania) published new progress about Antitumor agents. 350-03-8 belongs to class pyridine-derivatives, and the molecular formula is C7H7NO, Reference of 350-03-8.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Alijevic, Omar; McHugh, Damian; Rufener, Lucien; Mazurov, Anatoly; Hoeng, Julia; Peitsch, Manuel published the artcile< An electrophysiological characterization of naturally occurring tobacco alkaloids and their action on human α4β2 and α7 nicotinic acetylcholine receptors>, Category: pyridine-derivatives, the main research area is Nicotiana solanaceae tobacco alkaloids nAChR nicotine anabasine anatabine; Anabasine; Anatabine; Nicotiana tabacum; Nicotine; Nornicotine; Solanaceae; Tobacco alkaloids; nAChR; α4β2; α7.

Nicotinic acetylcholine receptor (nAChR) subtype-selective pharmacol. profiles of tobacco alkaloids are essential for understanding the physiol. effects of tobacco products. In this study, automated electrophysiol. was used to functionally characterize the effects of distinct groups of tobacco alkaloids on human α4β2 and α7 nAChRs. We found that, in tobacco alkaloids, pyridine as a hydrogen bond acceptor and a basic nitrogen atom at a distance of 4-7 Å are pharmacophoric elements necessary for mol. recognition by α4β2 and α7 nAChRs with various degrees of selectivity, potency, and efficacy. While four alkaloids-nicotine, nornicotine, anabasine and R-anatabine-potently activated α4β2, they were also weak agonists of α7 nAChRs. Nicotine was the most potent agonist of α4β2, while anabasine elicited the highest activation of α7. None of the tobacco alkaloids enhanced nAChR activity elicited by the endogenous ligand acetylcholine; therefore, none was considered to be a pos. allosteric modulator (PAM) of either α4β2 or α7 nAChRs. In contrast, we identified tobacco alkaloids, such as the tryptophan metabolite 6-hydroxykynurenic acid, that decreased the activity of both α4β2 and α7 nAChRs. Our study identified a class of alkaloids with pos. and neg. effects against human α4β2 and α7 nAChRs. It also revealed human α4β2 to be the principal receptor for sensing the most abundant alkaloids in tobacco leaves.

Phytochemistry (Elsevier) published new progress about Alkaloids Role: BSU (Biological Study, Unclassified), BIOL (Biological Study) (tobacco alkaloids). 581-47-5 belongs to class pyridine-derivatives, and the molecular formula is C10H8N2, Category: pyridine-derivatives.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Jalba, Angela; Regnier, Noemie; Ollevier, Thierry published the artcile< Enantioselective Aromatic Sulfide Oxidation and Tandem Kinetic Resolution Using Aqueous H2O2 and Chiral Iron-Bis(oxazolinyl)bipyridine Catalysts>, Application In Synthesis of 147409-41-4, the main research area is aromatic sulfoxide sulfone enantioselective preparation; arylsulfide enantioselective oxidation iron chiral ligand catalyst.

An efficient method for the oxidation of aromatic sulfides has been developed by using aqueous H2O2, catalyzed by the in situ generated chiral Fe/6,6′-bis(4-isopropyloxazolin-2-yl)-2,2′-bipyridine (bipybox-iPr) complex. The corresponding sulfoxides were obtained with high enantioselectivities (up to 98.5:1.5 er) and in good yields (up to 61 %) when the mono-oxidation of the sulfides was performed in combination with the kinetic resolution of the sulfoxide into the sulfone.

European Journal of Organic Chemistry published new progress about Amino alcohols, chiral Role: RCT (Reactant), RACT (Reactant or Reagent). 147409-41-4 belongs to class pyridine-derivatives, and the molecular formula is C22H26N4O2, Application In Synthesis of 147409-41-4.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Jiang, Xiaoli; Han, Bo; Xue, Yuhang; Duan, Mei; Gui, Zhuofan; Wang, You; Zhu, Shaolin published the artcile< Nickel-catalysed migratory hydroalkynylation and enantioselective hydroalkynylation of olefins with bromoalkynes>, Category: pyridine-derivatives, the main research area is benzylic alkyne preparation regioselective chemoselective; alkene bromoalkyne migratory hydroalkynation nickel catalyst; chiral benzylic alkyne preparation chemoselective enantioselective; styrene bromoalkyne hydroalkynation nickel catalyst.

Here, an NiH-catalyzed reductive migratory hydroalkynation of olefins such as, 4-phenyl-1-butene, (E)-1,2-diphenylethene, 1H-indene, etc. with bromoalkynes RCCBr [R = tris(propan-2-yl)silyl, triphenylmethyl, tert-butyldiphenylsilyl] that delivers the corresponding benzylic alkynation products ArCH(CH2R1)CCR [Ar = Ph, naphthalen-2-yl, thiophen-3-yl, etc.; R1 = H, Et, 2-cyclohexylethyl, Ph, etc.] in high yields with excellent regioselectivities was reported. Catalytic enantioselective hydroalkynation of styrenes (E/Z)-Ar1CH=CHR2 [Ar1 = Ph, 2-methoxyphenyl, thiophen-3-yl, etc.; R2 = H, Me, Et, Ph, etc.] has also been realized using a simple chiral PyrOx ligand. The obtained enantioenriched benzylic alkynes (S)-Ar1CH(CH2R2)CCR [R = tris(propan-2-yl)silyl, triethylsilyl, tert-butyldimethylsilyl, etc.] are versatile synthetic intermediates and can be readily transformed into synthetically useful chiral synthons.

Nature Communications published new progress about Alkenes Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 1416819-91-4 belongs to class pyridine-derivatives, and the molecular formula is C13H15F3N2O, Category: pyridine-derivatives.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Beddoe, Samuel V. F.; Lonergan, Rhona F.; Pitak, Mateusz B.; Price, Jason R.; Coles, Simon J.; Kitchen, Jonathan A.; Keene, Tony D. published the artcile< All about that base: investigating the role of ligand basicity in pyridyl complexes derived from a copper-Schiff base coordination polymer>, Recommanded Product: 2,4-Bipyridine, the main research area is copper hydroxybenzylideneaminophenol pyridine benzimidazole complex preparation; crystal structure copper hydroxybenzylideneaminophenol pyridine benzimidazole complex.

The role of ligand basicity in complex formation was studied using monodentate pyridyls or benzimidazole (mP) in combination with a solution-stable species derived form a coordination polymer, [Cu(L)] (L = 2-(2-hydroxybenzylidene-amino)phenol). The 12 [Cu(L)(mP)n] generated, combined with the {[Cu(L)]2(pP)} complexes from the authors’ previous work (pP is a polypyridyl ligand), allow the authors to gauge the likelihood of complex formation based on the pKa of the conjugate acid of the pyridyl ligands and Hammett parameter, σ. Above pKa ≈ 4.5, complexes are formed where the only ligands are L2- and mP or pP and the packing interactions are predominantly van der Waals. Below this value, complex formation is unlikely unless there are addnl. oxygen ligands in the Jahn-Teller axis of the Cu(II) ion. The structures of two literature [Cu(L)(bP)], where bP is a chelating bidentate pyridyl ligand are also reexamined to resolve the positional disorder in the [Cu(L)] moiety.

Dalton Transactions published new progress about Crystal structure. 581-47-5 belongs to class pyridine-derivatives, and the molecular formula is C10H8N2, Recommanded Product: 2,4-Bipyridine.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem