Tag: M.W=200-250

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

Liao, Lihao published the artcileSelenium-π-Acid Catalyzed Oxidative Functionalization of Alkynes: Facile Access to Ynones and Multisubstituted Oxazoles, Application In Synthesis of 107263-95-6, the publication is ACS Catalysis (2018), 8(7), 6745-6750, database is CAplus.

In the presence of di-Ph diselenide, N-fluoropyridinium triflates, and water, propargyl phosphonates such as PhCCCH₂P(:O)(OEt)₂ and β,γ-alkynoates underwent regioselective oxidation to yield γ-ketoalkynyl phosphonates such as PhCOCCP(:O)(OEt)₂ and γ-keto-α,β-alkynoates. Ynamides such as PhCCN(CH₂Ph)R (R = MeSO₂, PhSO₂, 4-MeC₆H₄SO₂, 4-O₂NC₆H₄) underwent regioselective oxidative cycloadditions with acetonitrile or butanenitrile mediated by Selectfluor in the presence of di-Ph selenide to yield aminooxazoles such as I (R = MeSO₂, PhSO₂, 4-MeC₆H₄SO₂, 4-O₂NC₆H₄). N-Propargylamides underwent oxidative cyclization in the presence of di-Ph diselenide and mediated by Selectfluor to give 2-substituted-5-oxazolecarboxaldehydes. In all cases, the reactions are likely to involve the reactions of cationic phenylselenium species with alkynes to generate vinylselenium cations. The mechanism of the reactions were studied; vinyl selenides were prepared by reactions of phenylselenium triflate with propargyl phosphonates and ynamides and shown to yield the observed ketone and oxazole products upon elimination, while isotopic labeling experiments were undertaken to determine the fate of added water.

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, Application In Synthesis of 107263-95-6.

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

Zhang, Yu published the artcileA new tetraphosphine and its application in Pd-catalyzed Suzuki cross-coupling reaction, Recommanded Product: 5-Nitro-2-phenylpyridine, the publication is Youji Huaxue (2012), 32(4), 790-793, database is CAplus.

A new tetraphosphine, N,N,N’,N’-tetra(diphenylphosphinomethyl)-cyclohexane-1,2-diamine has been designed and synthesized from the com. available cyclohexane-1,2-diamine as starting material. This tetraphosphine in combination with [Pd(η³-C₃H₅)Cl]₂ is a very efficient catalyst for Suzuki cross-coupling reaction. Various aryl and heteroaryl chlorides or bromides could be successfully transformed to the desired products in up to 99% yield with 0.1 mol% catalyst loading.

Youji Huaxue 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 C7H7ClN2S, Recommanded Product: 5-Nitro-2-phenylpyridine.

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

Baba, Daisuke published the artcileElectrolytic partial fluorination of organic compounds. Part 62. Highly diastereoselective anodic fluorination of chiral 1,3-oxathiolan-5-ones derived from camphorsulfonamides, Quality Control of 107263-95-6, the publication is Journal of Fluorine Chemistry (2003), 121(1), 93-96, database is CAplus.

Anodic fluorination of chiral 1,3-oxathiolan-5-ones, derived from camphorsulfonamide and thioglycolic acid, was carried out under various conditions. When dimethoxyethane (DME) containing Et₄NF·4HF was used, the corresponding monofluorinated products were obtained in good yield as a single diastereomer. Chem. fluorination was also attempted using N-fluoropyridinium salts; however, fluorination did not proceed at all. The anodic fluorination of (+)-(1R,2R,4R)-7,7-dimethyl-N,N-bis(1-methylethyl)-5′-oxo-spiro[bicyclo[2.2.1]heptane-2,2′-[1,3]oxathiolane]-1-methanesulfonamide gave (+)-(1R,2R,4R,4′S)-4′-Fluoro-7,7-dimethyl-N,N-bis(1-methylethyl)-5′-oxo-spiro[bicyclo[2.2.1]heptane-2,2′-[1,3]oxathiolane]-1-methanesulfonamide (I). Crystal and mol. structures of I were reported.

Journal of Fluorine Chemistry 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, Quality Control of 107263-95-6.

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

Lou, Shao-Jie published the artcilePd(OAc)₂-catalyzed regioselective aromatic C-H bond fluorination, Category: pyridine-derivatives, the publication is Chemical Communications (Cambridge, United Kingdom) (2013), 49(55), 6218-6220, database is CAplus and MEDLINE.

A novel Pd(OAc)₂-NFSI-TFA system was developed for the highly selective ortho-monofluorination directed by diverse aryl-N-heterocyclic directing groups e.g., quinoxaline, pyrazole, benzo[d]oxazole, and pyrazine derivatives A Pd(ii/iv) catalytic cycle was proposed based on the ESI-MS/MS studies.

Chemical Communications (Cambridge, United Kingdom) 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, Category: pyridine-derivatives.

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

Novak, Michael published the artcileNitrenium ions from food-derived heterocyclic arylamine mutagens, Name: 5-Nitro-2-phenylpyridine, the publication is Journal of the American Chemical Society (1998), 120(7), 1643-1644, database is CAplus.

The pivalic acid esters I (X = N, Y = CH, R = H, Me; X = CH, Y = N, R = H), models for the ultimate mutagenic and carcinogenic metabolites of heterocyclic arylamines, undergo spontaneous uncatalyzed hydrolysis under physiol. pH conditions, but become unreactive under acidic conditions in which the pyridyl N atom is protonated. Kinetic comparisons with the biphenyl ester I (X = Y = CH, R = H) show that the limiting hydrolysis rate constant, k₀, is reduced by substitution of an N atom for a C atom by ∼10⁴ for an ortho substitution and ∼30 for a meta substitution. The hydrolysis rates of these esters are insensitive to added N₃^–, but this nucleophile has considerable effect on reaction products. These results are consistent with a mechanism in which rate-limiting N-O bond heterolysis yields a nitrenium ion that is competitively trapped by solvent and N₃^–. The selectivity ratios, k_az/k_s, for the corresponding ions II (X ≠ Y) are ∼10-300-fold smaller than k_az/k_s for the 4-biphenylylnitrenium ion, II (X = Y = CH).

Journal of the American Chemical Society 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, Name: 5-Nitro-2-phenylpyridine.

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

Pereira, Raul published the artcileSynthesis and characterization of a novel N-F reagent derived from the ethano-Tröger’s base: ¹J_FN coupling constants as a signature for the N-F bond, Application In Synthesis of 107263-95-6, the publication is Chemical Communications (Cambridge, United Kingdom) (2016), 52(8), 1606-1609, database is CAplus and MEDLINE.

Methylation of 2,8-dimethyl-6H,12H-5,11-ethanodibenzo[b,f][1,5]-diazocine (ethano-Troddoger’s base) with Me iodide followed by ion metathesis and fluorination with N-fluoro-2,3,4,5,6-pentachloropyridinium triflate affords a new electrophilic N-F reagent, that is more reactive than Selectfluor. 2D ¹⁹F-¹⁵N HMQC experiments provide ¹J_NF coupling constants which are diagnostic for the N-F functional group.

Chemical Communications (Cambridge, United Kingdom) 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

Shen, Xuan published the artcileNew 2-phenyl-5-nitropyridyl containing iridium(III) cyclometalated complexes: syntheses, structures, electrochemistry and photophysical properties, Application of 5-Nitro-2-phenylpyridine, the publication is Inorganic Chemistry Communications (2011), 14(9), 1511-1515, database is CAplus.

New 2-phenyl-5-nitropyridyl containing iridium(III) cyclometalated complexes ([Ir(5-NO₂-ppy)₂Cl]₂ (1, 5-NO₂-ppy = 2-phenyl-5-nitropyridyl), [Ir(5-NO₂-ppy)₂(PPh₃)Cl] (2, PPh₃ = triphenylphosphine), [Ir(5-NO₂-ppy)₂(pic)] (3, pic = picolinic acid)) were synthesized and unambiguously characterized. The crystal structures of 2 and 3 were determined by x-ray diffraction analyses. The HOMO-LUMO energy gaps of 1–3 estimated by the cyclic voltammetry (CV) show values in the order of 2 > 3 > 1. The UV-visible absorption and the solid photoluminescence (PL) spectra of 1–3 also were measured, exhibiting the changing orders being consistent with that of the HOMO-LUMO energy gaps. Also, the UV-visible absorption spectra of 1–3 show obvious red shifts compared with those of the corresponding 2-phenylpyridyl (ppy) containing Ir(III) complexes ([Ir(ppy)₂Cl]₂, Ir(ppy)₂(PPh₃)Cl and Ir(ppy)₂(pic)) in which no strongly electron-withdrawing nitro groups are introduced to the pyridyl rings of the ppy ligands. Thus, the HOMO-LUMO energy gaps of 1–3 should be narrower than those of [Ir(ppy)₂Cl]₂, Ir(ppy)₂(PPh₃)Cl and Ir(ppy)₂(pic).

Inorganic Chemistry Communications 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 C13H10N2S, Application of 5-Nitro-2-phenylpyridine.

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

Zhao, Rui published the artcileSyntheses, structures and properties of cyclometalated iridium(III) complexes based on 2-phenyl-5-nitropyridyl and different strong-field ancillary ligands, HPLC of Formula: 89076-64-2, the publication is Inorganica Chimica Acta (2014), 409(PB), 372-378, database is CAplus.

The reactions of [Ir(5-NO₂-ppy)₂(PPh₃)Cl] (5-NO₂-ppy = 2-phenyl-5-nitropyridyl, PPh₃ = PPh₃, 1) with pseudohalides, replacing the weak π donor Cl^– with strong σ donors and π acceptors, lead to three new Ir(III) cyclometalated complexes [Ir(5-NO₂-ppy)₂(PPh₃)(L)] (L = NCO^–, 2; NCS^–, 3; N₃^–, 4) based on 2-phenylpyridyl (ppy) derivative, PPh₃ and different pseudohalogen strong-field ancillary ligands. 2–4 Are unambiguously characterized and their crystal structures are also determined by x-ray crystallog. The HOMO-LUMO electronic energy gaps of 1–4 estimated from the cyclic voltammetry measurements are comparable with those calculated from the UV-visible absorption spectra, which are both in the order of 3 > 1 > 2 > 4. Also, the electrochem. and photophys. properties of 1–4 show that the introduction of the electron-withdrawing nitro group to the pyridyl ring of the ppy backbone narrows the HOMO-LUMO electronic energy gaps, compared with those of corresponding ppy-containing Ir(III) complexes.

Inorganica Chimica Acta 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 C18H28B2O4, HPLC of Formula: 89076-64-2.

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