Tag: 100-200

Synthesis of some fluorine-containing pyridinealdoximes of potential use for the treatment of organophosphorus nerve-agent poisoning was written by Timperley, Christopher M.;Banks, R. Eric;Young, Ian M.;Haszeldine, Robert N.. And the article was included in Journal of Fluorine Chemistry in 2011.Recommanded Product: 399-88-2 This article mentions the following:

Fluoroheterocyclic aldoximes were screened as therapeutic agents for the treatment of anticholinesterase poisoning. 2-Fluoropyridine-3- and -6-aldoxime and 3-fluoropyridine-2- and -4-aldoxime were synthesized. Attempts to obtain 3,5,6-trifluoropyridine-2,4-bis(aldoxime) and -2-aldoxime, however, proved unsuccessful. Pentafluorobenzaldoxime was prepared by oximation of pentafluorobenzaldehyde. Acid dissociation constants (pK_a) and second-order rate constants (k_ox-) of the fluorinated pyridinealdoximes towards sarin were measured. 2,3,5,6-Tetrafluoropyridine-4-aldoxime had the best profile: its k_ox– approached that of the therapeutic oxime P2S (310 vs. 120 l mol^-1 min^-1), but its higher pK_a (9.1 vs. 7.8) fell short of the target figure of 8 required for reactivation of inhibited acetylcholinesterase in vivo. N-alkylation of the fluorinated pyridine-aldoximes may reduce their pK_a nearer to 8 and enhance their therapeutic potential. In the experiment, the researchers used many compounds, for example, 3-Fluoro-4-methylpyridine (cas: 399-88-2Recommanded Product: 399-88-2).

3-Fluoro-4-methylpyridine (cas: 399-88-2) belongs to pyridine derivatives. Pyridine has a dipole moment and a weaker resonant stabilization than benzene (resonance energy 117 kJ·mol−1 in pyridine vs. 150 kJ·mol−1 in benzene). Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Recommanded Product: 399-88-2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Aqueous biphasic systems composed of ionic liquids and polypropylene glycol: insights into their liquid-liquid demixing mechanisms was written by Neves, Catarina M. S. S.;Shahriari, Shahla;Lemus, Jesus;Pereira, Jorge F. B.;Freire, Mara G.;Coutinho, Joao A. P.. And the article was included in Physical Chemistry Chemical Physics in 2016.Product Details of 125652-55-3 This article mentions the following:

Novel ternary phase diagrams of aqueous biphasic systems (ABSs) composed of polypropylene glycol with an average mol. weight of 400 g mol^-1 (PPG-400) and a vast number of ionic liquids (ILs) were determined The large array of selected ILs allowed us to evaluate their tuneable structural features, namely the effect of the anion nature, cation core and cation alkyl side chain length on the phase behavior. Addnl. evidence on the mol.-level mechanisms which rule the phase splitting was obtained by ¹H NMR (NMR) spectroscopy and by COSMO-RS (Conductor-like Screening Model for Real Solvents). Some systems, for which the IL-PPG-400 pairs are completely miscible, revealed to be of type “0”. All data collected suggest that the formation of PPG-IL-based ABSs is controlled by the interactions established between the IL and PPG, contrarily to previous reports where a “salting-out” phenomenon exerted by the IL over the polymer in aqueous media was proposed as the dominant effect in ABS formation. The influence of temperature on the liquid-liquid demixing was also evaluated. In general, an increase in temperature favors the formation of an ABS in agreement with the lower critical solution temperature (LCST) phase behavior usually observed in polymer-IL binary mixtures Partition results of a dye (chloroanilic acid, in its neutral form) further confirm the possibility of tailoring the phases’ polarities of IL-PPG-based ABSs. In the experiment, the researchers used many compounds, for example, 1-Butyl-3-methylpyridinium Chloride (cas: 125652-55-3Product Details of 125652-55-3).

1-Butyl-3-methylpyridinium Chloride (cas: 125652-55-3) belongs to pyridine derivatives. Pyridine is diamagnetic and has a diamagnetic susceptibility of −48.7 × 10−6 cm3·mol−1.The molecular electric dipole moment is 2.2 debyes. The standard enthalpy of formation is 100.2 kJ·mol−1 in the liquid phase and 140.4 kJ·mol−1 in the gas phase. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Product Details of 125652-55-3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Visible Light-Induced Sulfonylation/Arylation of Styrenes in a Double Radical Three-Component Photoredox Reaction was written by Lipp, Benjamin;Kammer, Lisa Marie;Kuecuekdisli, Murat;Luque, Adriana;Kuehlborn, Jonas;Pusch, Stefan;Matuleviciute, Gita;Schollmeyer, Dieter;Sackus, Algirdas;Opatz, Till. And the article was included in Chemistry – A European Journal in 2019.Safety of 4-Methylpicolinonitrile This article mentions the following:

Simultaneous sulfonylation/arylation of styrene derivatives is achieved in a photoredox-catalyzed three-component reaction using visible light. A broad variety of difunctionalized products is accessible in mostly excellent yields and high diastereoselectivity. The developed reaction is scalable and suitable for the modification of styrene-functionalized biomols. Mechanistic investigations suggest the transformation to be operating through a designed sequence of radical formation and radical combination. In the experiment, the researchers used many compounds, for example, 4-Methylpicolinonitrile (cas: 1620-76-4Safety of 4-Methylpicolinonitrile).

4-Methylpicolinonitrile (cas: 1620-76-4) belongs to pyridine derivatives. Pyridine’s the lone pair does not contribute to the aromatic system but importantly influences the chemical properties of pyridine, as it easily supports bond formation via an electrophilic attack. One of the examples of pyridines is the well-known alkaloid lithoprimidine, which is an A3 adenosine receptor antagonist and N,N-dimethylaminopyridine (DMAP) analog, commonly used in organic synthesis.Safety of 4-Methylpicolinonitrile

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Transfer hydrogenation via generation of hydride intermediate and base-free alcohol oxidation activity studies on designed ruthenium complexes derived from NNN pincer type ligands was written by Singh, Prasoon Raj;Maji, Ankur;Singh, Ovender;Singh, Udai P.;Ghosh, Kaushik. And the article was included in Applied Organometallic Chemistry in 2020.Electric Literature of C12H9NO This article mentions the following:

Ruthenium complexes(1-3) were synthesized using pincer-type ligands L¹ = (E)-2-((2-phenyl-2-(pyridin-2-yl)hydrazono)methyl)pyridine, L² = (E)-2-(1-phenyl-2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)pyridine, L³ = (E)-2-(phenyl(2-phenyl-2-(pyridin-2-yl)hydrazono) Me)pyridine. The mol. structures of all the complexes 1, 2 and 3 were determined by using single crystal x-ray diffraction. These complexes showed excellent catalytic activities such as transfer hydrogenation and alc. oxidation Theor. calculations were performed to understand the electronic properties of all the complexes using B3LYP as a function and LANL2DZ as a basis set. In the experiment, the researchers used many compounds, for example, Phenyl(pyridin-2-yl)methanone (cas: 91-02-1Electric Literature of C12H9NO).

Phenyl(pyridin-2-yl)methanone (cas: 91-02-1) belongs to pyridine derivatives. The ring atoms in the pyridine molecule are sp2-hybridized. The nitrogen is involved in the π-bonding aromatic system using its unhybridized p orbital. The lone pair is in an sp2 orbital, projecting outward from the ring in the same plane as the σ bonds. One of the examples of pyridines is the well-known alkaloid lithoprimidine, which is an A3 adenosine receptor antagonist and N,N-dimethylaminopyridine (DMAP) analog, commonly used in organic synthesis.Electric Literature of C12H9NO

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Fast olefin metathesis: synthesis of 2-aryloxy-substituted Hoveyda-type complexes and application in ring-closing metathesis was written by Kos, Pavlo;Savka, Roman;Plenio, Herbert. And the article was included in Advanced Synthesis & Catalysis in 2013.SDS of cas: 85838-94-4 This article mentions the following:

Compounds I (R = NMe₂, H, Cl, NO₂) were reacted with the ruthenium complexes [RuCl₂(NHC)(3-phenylindenylidene)(py)] in the presence of a protic resin to result in the formation of the resp. Hoveyda-type complexes II (R = NMe₂, H, Cl, NO₂) and III (R = NMe₂, H, Cl, NO₂) in 66-84% yield. The lower steric bulk and the decreased donation of the diaryl ether oxygen atoms in complexes II and III led to rapidly initiating precatalysts. The Ru(II/III) redox potentials of complexes III were determined (ΔE=0.89-1.08 V). In the crystal structure of II (R = H) two independent mols. were observed in the unit cell, displaying Ru-O distances of 226.6(4) and 230.5(3) pm. The catalytic performance of complexes 5 and 6 in various ring-closing metathesis (RCM) reactions was studied. Catalyst loadings of between 15-200 ppm are sufficient for the formation of >90% yield of the resp. cyclic products. Complex III (R = H) catalyzes the formation of N-protected 2,5-dihydropyrroles with up to TON 64,000 and TOF 256,000 h^-1, of the N-protected 1,2,3,6- tetrahydropyridines with up to TON 18,200 and TOF 73,000 h^-1 and of the N-protected 2,3,6,7-tetrahydroazepines with up to TON 8,100 and TOF 32,000 h^-1 with yields ranging between 77 and 96%. In the experiment, the researchers used many compounds, for example, tert-Butyl 5,6-dihydropyridine-1(2H)-carboxylate (cas: 85838-94-4SDS of cas: 85838-94-4).

tert-Butyl 5,6-dihydropyridine-1(2H)-carboxylate (cas: 85838-94-4) belongs to pyridine derivatives. The ring atoms in the pyridine molecule are sp2-hybridized. The nitrogen is involved in the π-bonding aromatic system using its unhybridized p orbital. The lone pair is in an sp2 orbital, projecting outward from the ring in the same plane as the σ bonds. Reduced pyridines, namely tetrahydropyridines, dihydropyridines and piperidines, are found in numerous natural and synthetic compounds. The synthesis and reactivity of these compounds have often been driven by the fact many of these compounds have interesting and unique pharmacological properties. SDS of cas: 85838-94-4

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

A structure-activity relationship study of the toxicity of ionic liquids using an adapted Ferreira-Kiralj hydrophobicity parameter [Erratum to document cited in CA162:240673] was written by de Melo, Eduardo Borges. And the article was included in Physical Chemistry Chemical Physics in 2016.Recommanded Product: 17281-59-3 This article mentions the following:

The author discovered an error in the parameter N_H used in the published article; the study was carried out using the correct values and the corrected result values are given. In the experiment, the researchers used many compounds, for example, 1-(Cyanomethyl)pyridin-1-ium chloride (cas: 17281-59-3Recommanded Product: 17281-59-3).

1-(Cyanomethyl)pyridin-1-ium chloride (cas: 17281-59-3) belongs to pyridine derivatives. In contrast to benzene, Pyridine’s electron density is not evenly distributed over the ring, reflecting the negative inductive effect of the nitrogen atom. Pyridine derivatives are also useful as small-molecule α-helix mimetics that inhibit protein-protein interactions, as well as functionally selective GABA ligands.Recommanded Product: 17281-59-3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

A QSPR-approach to the estimation of the pK_HB of six-membered nitrogen-heterocycles using quantum mechanically derived descriptors was written by Hennemann, Matthias;Clark, Timothy. And the article was included in Journal of Molecular Modeling [online computer file] in 2002.Safety of 2-Isopropylpyridine This article mentions the following:

Descriptors derived from semiempirical (AM1) MO calculations have been used to construct a quant. structure-property relationship (QSPR) for the thermodn. hydrogen-bond basicity, pK_HB, of a series of six-membered aromatic nitrogen-heterocycles. The resulting model uses four-descriptors (the Coulson charge on the nitrogen atom, the energy of the localized nitrogen lone-pair orbital, the p-orbital contribution to this MO and an accessibility angle). The model gives r²_ev=0.95 for 51 compounds with a standard deviation between calculation and experiment of 0.13 log units. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Safety of 2-Isopropylpyridine).

2-Isopropylpyridine (cas: 644-98-4) belongs to pyridine derivatives. The ring atoms in the pyridine molecule are sp2-hybridized. The nitrogen is involved in the π-bonding aromatic system using its unhybridized p orbital. The lone pair is in an sp2 orbital, projecting outward from the ring in the same plane as the σ bonds. Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Safety of 2-Isopropylpyridine

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Oxidant-Induced Azolation of Electron-Rich Phenol Derivatives was written by Wang, Xiaoyu;Wang, Shengchun;Gao, Yiming;Sun, He;Liang, Xing’an;Bu, Faxiang;Abdelilah, Takfaoui;Lei, Aiwen. And the article was included in Organic Letters in 2020.Reference of 51834-97-0 This article mentions the following:

An oxidant-induced intermol. azolation of phenol derivatives was demonstrated under catalyst-free condition. Both monoazolation and diazolation of phenols was successfully achieved via this practical and powerful method. In the experiment, the researchers used many compounds, for example, 5-Hydroxy-2-methoxylpyridine (cas: 51834-97-0Reference of 51834-97-0).

5-Hydroxy-2-methoxylpyridine (cas: 51834-97-0) belongs to pyridine derivatives. The ring atoms in the pyridine molecule are sp2-hybridized. The nitrogen is involved in the π-bonding aromatic system using its unhybridized p orbital. The lone pair is in an sp2 orbital, projecting outward from the ring in the same plane as the σ bonds. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Reference of 51834-97-0

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Heterogeneous catalytic oxidation of pyridines to N-oxides under mild conditions using tungsten-loaded TiO₂ was written by Li, Qing-Feng;Luo, Wen;Lu, Wei;Wang, Zhenling. And the article was included in Reaction Kinetics, Mechanisms and Catalysis in 2016.Electric Literature of C7H9NO This article mentions the following:

The heterogeneous catalytic oxidation of pyridines to pyridine N-oxides has been studied using tungsten-loaded TiO₂ as the catalyst and hydrogen peroxide as the green oxidant. The catalysts were synthesized by a simple impregnation technique and characterized by X-ray powder diffraction, Raman spectroscopy, transmission electron microscopy, energy dispersion X-ray spectroscopy, XPS. The catalytic performances of the catalysts were evaluated by the N-oxidation of pyridines with 30 weight% H₂O₂ solution as an environmentally friendly oxidant at room temperature These processes serve as an efficient method to prepare a variety of pyridine-N-oxides in modest to high yields, and the pyridine N-oxides could be easily separated from the heterogeneous catalytic system. This study will provide a useful strategy for preparation of heterocyclic N-oxides in the mild condition. In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Electric Literature of C7H9NO).

3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8) belongs to pyridine derivatives. Pyridine has a dipole moment and a weaker resonant stabilization than benzene (resonance energy 117 kJ·mol−1 in pyridine vs. 150 kJ·mol−1 in benzene). One of the examples of pyridines is the well-known alkaloid lithoprimidine, which is an A3 adenosine receptor antagonist and N,N-dimethylaminopyridine (DMAP) analog, commonly used in organic synthesis.Electric Literature of C7H9NO

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Radical-Based Regioselective C-H Functionalization of Electron-Deficient Heteroarenes: Scope, Tunability, and Predictability was written by O’Hara, Fionn;Blackmond, Donna G.;Baran, Phil S.. And the article was included in Journal of the American Chemical Society in 2013.Reference of 59718-84-2 This article mentions the following:

Radical addition processes can be ideally suited for the direct functionalization of heteroaromatic bases, yet these processes are only sparsely used due to the perception of poor or unreliable control of regiochem. A systematic investigation of factors affecting the regiochem. of radical functionalization of heterocycles using alkylsulfinate salts revealed that certain types of substituents exert consistent and additive effects on the regioselectivity of substitution. This allowed us to establish guidelines for predicting regioselectivity on complex π-deficient heteroarenes, including pyridines, pyrimidines, pyridazines, and pyrazines. Since the relative contribution from opposing directing factors was dependent on solvent and pH, it was sometimes possible to tune the regiochem. to a desired result by modifying reaction conditions. This methodol. was applied to the direct, regioselective introduction of iso-Pr groups into complex, biol. active mols., such as diflufenican (I; R = H → R = iso-Pr) and nevirapine (II; R = H → R = iso-Pr). In the experiment, the researchers used many compounds, for example, Methyl 3-methylpicolinate (cas: 59718-84-2Reference of 59718-84-2).

Methyl 3-methylpicolinate (cas: 59718-84-2) belongs to pyridine derivatives. Pyridine has a conjugated system of six π electrons that are delocalized over the ring. The molecule is planar and, thus, follows the Hückel criteria for aromatic systems. Pyridine derivatives are also useful as small-molecule α-helix mimetics that inhibit protein-protein interactions, as well as functionally selective GABA ligands.Reference of 59718-84-2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem