Day: December 9, 2022

Alshreimi, Abdullah S. published the artcileSynthesis of Spirocyclic 1-Pyrrolines from Nitrones and Arynes through a Dearomative [3,3′]-Sigmatropic Rearrangement, Category: pyridine-derivatives, the publication is Angewandte Chemie, International Edition (2020), 59(35), 15244-15248, database is CAplus and MEDLINE.

A dearomative [3,3′]-sigmatropic rearrangement that converts N-alkenylbenzisoxazolines into spirocyclic pyrroline cyclohexadienones, e.g., I, has been developed by using the dipolar cycloaddition of an N-alkenylnitrone and an aryne to access these unusual transient rearrangement precursors. This cascade reaction affords spirocyclic pyrrolines that are inaccessible through dipolar cycloadditions of exocyclic cyclohexenones and provides a fundamentally new approach to novel spirocyclic pyrroline and pyrrolidine motifs that are common scaffolds in biol.-active mols. Diastereoselective functionalization processes have also been explored to demonstrate the divergent synthetic utility of the unsaturated spirocyclic products.

Angewandte Chemie, International Edition 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, Category: pyridine-derivatives.

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

Liu, Xuemei published the artcileEffect of halogenated substituents on the metabolism and estrogenic effects of the equine estrogen, equilenin, Application In Synthesis of 107263-95-6, the publication is Chemical Research in Toxicology (2003), 16(6), 741-749, database is CAplus and MEDLINE.

Estrogen replacement therapy has been correlated with an increased risk for developing breast and endometrial cancers. One potential mechanism of estrogen carcinogenesis involves metabolism of estrogens to 2- and 4-hydroxylated catechols, which are further oxidized to electrophilic/redox active o-quinones that have the potential to both initiate and promote the carcinogenic process. Previously, the authors showed that the equine estrogens, equilin and equilenin, which are major components of the estrogen replacement formulation Premarin (Wyeth-Ayerst), are primarily metabolized to the catechol, 4-hydroxyequilenin. This catechol was found to autoxidize to an o-quinone causing oxidation and alkylation of DNA in vitro and in vivo. To block catechol formation from equilenin, 4-halogenated equilenin derivatives were synthesized. These derivatives were tested for their ability to bind to the estrogen receptor, induce estrogen sensitive genes, and their potential to form catechol metabolites. The authors found that the 4-fluoro derivatives were more estrogenic than the 4-chloro and 4-bromo derivatives as demonstrated by a higher binding affinity for estrogen receptors α and β, an enhanced induction of alk. phosphatase activity in Ishikawa cells, pS2 expression in S30 cells, and PR expression in Ishikawa cells. Incubation of these compounds with tyrosinase in the presence of GSH showed that the halogenated equilenin compounds formed less catechol GSH conjugates than the parent compounds, equilenin and 17β-hydroxyequilenin. In addition, these halogenated compounds showed less cytotoxicity in the presence of tyrosinase than the parent compounds in S30 cells. Also, as stated above, the 4-fluoro derivatives showed similar estrogenic effects as compared with parent compounds; however, they were less toxic in S30 cells as compared to equilenin and 17β-equilenin. Because 17β-hydroxy-4-halogenated equilenin derivatives showed higher estrogenic effects than the halogenated equilenin derivatives in vitro, the authors studied the relative ability of the 17β-hydroxy-4-halogenated equilenin derivatives to induce estrogenic effects in the ovariectomized rat model. The 4-fluoro derivative showed higher activity than 4-chloro and 4-bromo derivatives as demonstrated by inducing higher vaginal cellular differentiation, uterine growth, and mammary gland branching. However, 17β-hydroxy-4-fluoroequilenin showed a lower estrogenic activity than 17β-hydroxyequilenin and estradiol, which could be due to alternative pharmacokinetic properties for these compounds These data suggest that the 4-fluoroequilenin derivatives have promise as alternatives to traditional estrogen replacement therapy due to their similar estrogenic properties with less overall toxicity.

Chemical Research in Toxicology published new progress about 107263-95-6. 107263-95-6 belongs to pyridine-derivatives, auxiliary class Fluorination reagent, name is 1-Fluoropyridiniumtriflate, and the molecular formula is C6H5F4NO3S, Application In Synthesis of 107263-95-6.

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

Liu, Lantao published the artcileAsymmetric Synthesis of Planar Chiral Ferrocenes by Enantioselective Intramolecular C-H Arylation of N-(2-Haloaryl)ferrocenecarboxamides, Application of 2-Bromopyridin-3-amine, the publication is Organic Letters (2014), 16(20), 5336-5338, database is CAplus and MEDLINE.

The palladium-catalyzed intramol. C-H arylation reaction of N-(2-bromoaryl)ferrocenecarboxamides furnishes planar chiral ferrocene derivatives TADDOL-derived phosphoramide ligands induce enantioselectivities ranging from 91:9 to 98:2 er.

Organic Letters published new progress about 39856-58-1. 39856-58-1 belongs to pyridine-derivatives, auxiliary class Pyridine,Bromide,Amine, name is 2-Bromopyridin-3-amine, and the molecular formula is C5H5BrN2, Application of 2-Bromopyridin-3-amine.

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

Yu, Han published the artcileVisible-Light-Activated Asymmetric Addition of Hydrocarbons to Pyridine-Based Ketones, Product Details of C12H9NO, the publication is ACS Catalysis (2022), 12(9), 5136-5144, database is CAplus.

A combined system involving Er(III)-based chiral Lewis acid catalysis, Ir(III)-based photoredox catalysis, and bromide-radical-mediated hydrogen atom transfer was disclosed. The introduction of a bulky and nonredox chiral Lewis acid through the photoredox pathway enabled the radical addition process and inhibited the above competitive reactions. The visible-light-promoted catalytic asym. alkylation of heteroaryl-based ketones with diverse hydrocarbons (mainly benzyl) delivered a variety of congested enantioenriched tertiary alcs. (up to 97% yield, 96% enantiomeric excess (ee)).

ACS Catalysis published new progress about 91-02-1. 91-02-1 belongs to pyridine-derivatives, auxiliary class Pyridine,Benzene,Ketone, name is Phenyl(pyridin-2-yl)methanone, and the molecular formula is C10H18O, Product Details of C12H9NO.

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

Dar’in, Dmitry published the artcileNon-chelating p-phenylidene-linked bis-imidazoline analogs of known influenza virus endonuclease inhibitors: Synthesis and anti-influenza activity, COA of Formula: C5H6BNO2, the publication is European Journal of Medicinal Chemistry (2019), 526-532, database is CAplus and MEDLINE.

A novel chemotype topol. similar to known influenza virus PA endonuclease inhibitors was designed. It was aimed to reproduce the extended topol. of the known metal-chelating ligands with a p-phenylidene-linked bis-imidazoline scaffold. It was envisioned that aromatic groups introduced to this scaffolds via metal-catalyzed N-arylation (Buchwald-Hartwig or Chan-Evans-Lam) would contribute to lipophilic binding to the target and one of the imidazoline nitrogen atoms would ensure non-chelating coordination to the prosthetic divalent metal ion. The compounds displayed appreciable anti-influenza activity in vitro and substantial concentration window from the general cytotoxicity range. Docking anal. of low-energy poses of the most active compound (as well as their comparison to the binding of an inactive compound) revealed that these compounds reproduced similar binding components to a known PA endonuclease inhibitor and displayed similar binding pose and desired monodentate metal coordination, as was initially envisioned. These findings warrant further study of the mechanism of action of the newly discovered series.

European Journal of Medicinal Chemistry 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, COA of Formula: C5H6BNO2.

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

Le Saux, Emilien published the artcilePhotochemical Organocatalytic Benzylation of Allylic C-H Bonds, Quality Control of 91-02-1, the publication is Journal of the American Chemical Society (2022), 144(3), 1113-1118, database is CAplus and MEDLINE.

Authors report a radical-based organocatalytic method for the direct benzylation of allylic C-H bonds. The process uses nonfunctionalized allylic substrates and readily available benzyl radical precursors and is driven by visible light. Crucial was the identification of a dithiophosphoric acid that performs two distinct catalytic roles, sequentially acting as a catalytic donor for the formation of photoactive electron donor-acceptor (EDA) complexes and then as a hydrogen atom abstractor. By mastering these orthogonal radical generation paths, the organic catalyst enables the formation of benzylic and allylic radicals, resp., to then govern their selective coupling. The protocol was also used to design a three-component radical process, which increased the synthetic potential of the chem.

Journal of the American Chemical Society published new progress about 91-02-1. 91-02-1 belongs to pyridine-derivatives, auxiliary class Pyridine,Benzene,Ketone, name is Phenyl(pyridin-2-yl)methanone, and the molecular formula is C12H9NO, Quality Control of 91-02-1.

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

Storozhenko, Olga A. published the artcileSynthesis of 2-aminochromene derivatives from 1-(2-imino-2H-chromen-3-yl)pyridin-1-ium perchlorates and nitromethane in basic medium, COA of Formula: C7H7ClN2, the publication is Chemistry of Heterocyclic Compounds (New York, NY, United States) (2020), 56(9), 1161-1166, database is CAplus.

Novel 2-amino-4-(nitromethylidene)chromenes were obtained as a result of the reaction of 1-(2-imino-2H-chromen-3-yl)pyridinium perchlorates and nitromethane by the action of DBU at reflux in trifluoroethanol. The starting 2-iminochromenes are readily accessible from the corresponding salicylic aldehydes and quaternary cyanomethyl pyridinium salts. The reaction is tolerant to substituents of different nature (alkyl, alkoxy, halogen); a limitation is the presence of strong electron-withdrawing substituents in the benzene ring of chromene. During the reaction, the products precipitate and can be isolated by filtration.

Chemistry of Heterocyclic Compounds (New York, NY, United States) published new progress about 17281-59-3. 17281-59-3 belongs to pyridine-derivatives, auxiliary class Pyridine,Nitrile,Salt, name is 1-(Cyanomethyl)pyridin-1-ium chloride, and the molecular formula is C9H5FO2, COA of Formula: C7H7ClN2.

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

Liu, Qilun published the artcileAbnormal Mesoionic Carbene Silver Complex: Synthesis, Reactivity, and Mechanistic Insight on Oxidative Fluorination, Recommanded Product: 1-Fluoropyridiniumtriflate, the publication is ACS Catalysis (2015), 5(11), 6732-6737, database is CAplus.

A silver-catalyzed intramol. amination of alkynyl-imine substrates has been extensively studied to build various isoquinoline derivatives efficiently. However, most of these transformations are limited to hydroamination, and the related oxidative reaction is quite rare. Importantly, the mechanistic details are still unknown, which retarded further progress in the field. In this work, a novel abnormal mesoionic carbene silver complex (MIC)_nAg(I) was isolated and fully characterized as the key intermediate. Further investigation on the oxidative transformation of the silver complex reveals that successful oxidative halogenation could be achieved with NXS (X = Cl, Br, and I), as well as F⁺ reagent. Surprisingly, the fluorination reaction occurred in the presence of both strong (SelectFluor) and weak (NFSI) fluorinating reagents, although the F-Py-type reagent, whose oxidative potential lies between, is ineffective. Further mechanistic studies disclosed that (1) from kinetic data, the (MIC)Ag(I) complex was proved to be the reactive intermediate in the fluorination reaction, and pyridyl-oxazoline (Pyox) ligand could significantly improve this transformation; (2) from DFT calculation results, two different mechanistic pathways were suggested to be involved, a metathesis process in the case of NFSI promoted by the chelation of sulfonyl group toward the silver center and a redox process in the case of SelectFluor due to its strong oxidative potential.

ACS Catalysis published new progress about 107263-95-6. 107263-95-6 belongs to pyridine-derivatives, auxiliary class Fluorination reagent, name is 1-Fluoropyridiniumtriflate, and the molecular formula is C6H5F4NO3S, Recommanded Product: 1-Fluoropyridiniumtriflate.

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

Dong, Jie published the artcileManganese-catalysed divergent silylation of alkenes, Application of 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, the publication is Nature Chemistry (2021), 13(2), 182-190, database is CAplus and MEDLINE.

Transition-metal-catalyzed, redox-neutral dehydrosilylation of alkenes is a long-standing challenge in organic synthesis, with current methods suffering from low selectivity and narrow scope. The authors report a general and simple method for the Mn-catalyzed dehydrosilylation and hydrosilylation of alkenes, with Mn₂(CO)₁₀ as a catalyst precursor, by using a ligand-tuned metalloradical reactivity strategy. This enables versatility and controllable selectivity with a 1:1 ratio of alkenes and silanes, and the synthetic robustness and practicality of this method are demonstrated using complex alkenes and light olefins. The selectivity of the reaction was studied using d. functional theory calculations, showing the use of an ⁱPrPNP ligand to favor dehydrosilylation, while a JackiePhos ligand favors hydrosilylation. The reaction is redox-neutral and atom-economical, exhibits a broad substrate scope and excellent functional group tolerance, and is suitable for various synthetic applications on a gram scale. [graphic not available: see fulltext].

Nature Chemistry 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

Zhang, Yin published the artcileDimensional Reduction of Eu-Based Metal-Organic Framework as Catalysts for Oxidation Catalysis of C(sp³)-H Bond, Formula: C12H9NO, the publication is Chinese Journal of Chemistry (2022), 40(4), 480-486, database is CAplus.

Developing new catalysts for highly selectivity and conversion of saturated C(sp³)-H bonds is of great significance. In order to obtain catalysts with high catalytic performance, six Eu-based MOFs with different structural characteristics were obtained by using europium ions and different organic acid ligands, namely Eu-1∼Eu-6. Eu-1, Eu-2 and Eu-3 featured three-dimensional structures, while Eu-4 and Eu-5 featured two-dimensional structures. Differently, a one-dimensional chain structure of Eu-6 was obtained by changing the ligand. All the six MOFs were applied to the catalytic reaction of C(sp³)-H bond, and it was found that the catalytic effect was gradually enhanced with the decrease of dimension and the increase of the size of channels. As expected, Eu-6 showed the highest selectivity (∼99%) and conversion (∼99%). Moreover, catalytic cycling and stability tests showed Eu-6 can be a reliable catalyst.

Chinese Journal of Chemistry published new progress about 91-02-1. 91-02-1 belongs to pyridine-derivatives, auxiliary class Pyridine,Benzene,Ketone, name is Phenyl(pyridin-2-yl)methanone, and the molecular formula is C14H10O4S2, Formula: C12H9NO.

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