Month: December 2022

Rhenium(I)-Catalyzed ortho-C-H Addition to Bicyclic Alkenes was written by Prakash, Sekar;Chang, Yu-Che;Cheng, Chien-Hong. And the article was included in Chemistry – An Asian Journal in 2018.COA of Formula: C12H11N This article mentions the following:

Hydroarylation of bicyclic alkenes was developed using a low-valent Re^I-catalyzed, directing group-assisted C-H bond activation strategy. The addition of sodium acetate significantly improves the reaction efficiency; moreover, bicyclic alkenes such as 7-oxa and aza benzonorbornadienes worked efficiently under this reaction condition. Preliminary mechanistic studies suggest that, after the alkene insertion, the rhenacycle preferentially undergoes protonolysis rather than reductive elimination. In the experiment, the researchers used many compounds, for example, 2-(m-Tolyl)pyridine (cas: 4373-61-9COA of Formula: C12H11N).

2-(m-Tolyl)pyridine (cas: 4373-61-9) belongs to pyridine derivatives. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. Several pyridine derivatives play important roles in biological systems. While its biosynthesis is not fully understood, nicotinic acid (vitamin B3) occurs in some bacteria, fungi, and mammals.COA of Formula: C12H11N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Nickel-Catalyzed Amination of (Hetero)aryl Halides Facilitated by a Catalytic Pyridinium Additive was written by Han, Dongyang;Li, Sasa;Xia, Siqi;Su, Mincong;Jin, Jian. And the article was included in Chemistry – A European Journal in 2020.COA of Formula: C6H3BrF3N This article mentions the following:

An efficient and operationally simple Ni-catalyzed amination protocol has been developed. This methodol. features a simple Ni^II salt, an organic base and catalytic amounts of both a pyridinium additive and Zn metal. A diverse number of (hetero)aryl halides RX (R = 4-methanesulfonylphenyl, 3-cyanopyridin-2-yl, 1,3-benzoxazol-2-yl, etc.; X = Br, Cl) were coupled successfully with primary and secondary alkyl amines and anilines such as cyclohexanamine, pyrrolidine, 4-methylaniline, etc. in good to excellent yields RR¹ [R¹ = cyclohexylaminyl, pyrrolidin-1-yl, (4-methylphenyl)aminyl, etc.]. Similarly, benzophenone imine gave the corresponding N-arylation product N-(4-(methylsulfonyl)phenyl)-1,1-diphenylmethanimine in an excellent yield. In the experiment, the researchers used many compounds, for example, 2-Bromo-3-(trifluoromethyl)pyridine (cas: 175205-82-0COA of Formula: C6H3BrF3N).

2-Bromo-3-(trifluoromethyl)pyridine (cas: 175205-82-0) 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. 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.COA of Formula: C6H3BrF3N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Infrared spectra of heterocyclic compounds. V. Infrared spectra of substituted pyridine 1-oxides was written by Shindo, Hideyo. And the article was included in Chemical & Pharmaceutical Bulletin in 1958.Synthetic Route of C7H9NO This article mentions the following:

The following derivatives of pyridine 1-oxide (I) were prepared by previously described methods (Ochiai, C.A. 48, 3359i)(substituent and m.p. given): 4-O₂N, 160°; 4-Cl, 169.5° (decomposition); 4-Br, 146° (decomposition); 4-MeO, 83°; 4-PhCH₂O, 176°; 3-O₂N, 172°; 3-NC, 178°; 3-Ac, 147°; 3-Br, about 40°; 3-Cl, 60°. The infrared spectra of these compounds were measured in CS₂ solution or in Nujol and the results tabulated, together with those of the 4-NC, 4-NaO₃S, 2-Me, 3-Me, 3-Et, 4-Me, 4-Et, 3,5-Me₂, 3,4-Me(O₂N), 3,4-Me(H₂N), 2,4-Me(O₂N), 2,6,4-Me₂(O₂N), 4-Ac, 4-EtO₂C, 3-EtO₂C, 3-H₂NCO, 4-H₂NCO, 3-H₂N, 4-H₂N, and 2-H₂N derivatives of I, and 4,4′-, 3,3′-, and 2,2′-bipyridine N,N’-dioxides. The results were discussed in terms of an electronic effect of the N-oxide group with relation to (1) its stretching frequencies (strong absorption in the region 1200-1300 cm.^-1) as affected by the electronic effect of the substituent, whereby a linear relation was found between these frequencies and the σ-value of the substituent, (2) the ring CH out-of-plane bending frequencies, which were shifted from those of the parent pyridines to a higher frequency for 2- and 4-substituted derivatives and to a lower for 3-substituted, (3) the ring CH in-plane bending mode and the ring double-bond stretching vibrations at 900-1200 and 1450-1630 cm.^-1, resp., both correlated with the positions of the substituents, and (4) the effect of the N-oxide group in shifting the absorption frequencies of the substituents, whereby the σ-values 0.25 and 1.18 were obtained for the 4- and 3-positions, resp., of I. In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Synthetic Route of C7H9NO).

3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8) 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 groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Synthetic Route of C7H9NO

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Electron paramagnetic resonance study of the radiolysis of pyridine N-oxide in a methanol vitreous matrix was written by Quaegebeur, J. P.;Perly, B.;Surpateanu, G.;Lablache-Combier, A.. And the article was included in Canadian Journal of Chemistry in 1977.Recommanded Product: 3718-65-8 This article mentions the following:

The title ESR spectra showed a mixture of radicals I and II, identified by comparison with ESR of substituted pyridine N-oxides. Addition of the HOCH₂• radical to the 3-position was not detected. In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Recommanded Product: 3718-65-8).

3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8) 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. 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.Recommanded Product: 3718-65-8

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Effect of 1-butyl-4-methylpyridinium and 1-butyl-3-methylimidazolium halide ionic liquids on the interactions of lactic acid in the aqueous solutions of polyethylene glycol was written by Mehrdad, Abbas;Shekaari, Hemayat;Noorani, Narmin. And the article was included in Journal of Chemical Thermodynamics in 2017.Recommanded Product: 1-Butyl-4-methylpyridin-1-ium bromide This article mentions the following:

In this study, effect of some ionic liquids on the thermodn. and transport properties of L(+)-lactic acid in aqueous polyethylene glycol solutions have been investigated. D., speed of sound, and viscosity of L(+)-lactic acid in the aqueous solutions of polyethylene glycol, polyethylene glycol +1-butyl-3-methylimidazolium bromide, polyethylene glycol +1-butyl-3-methylimidazolium chloride, polyethylene glycol +1-butyl-4-methylpyridinium bromide, and polyethylene glycol +1-butyl-4-methylpyridinium chloride were measured at T/K = (288.15, 298.15, 308.15 and 318.15). Infinite dilution apparent molar volumes, transfer apparent molar volume, infinite dilution apparent molar isentropic compressibility and viscosity B-coefficient of L(+)-lactic acid were calculated using exptl. data and were discussed in terms of solute-solute and solute-solvent interactions. The results reveal that solute-solvent interactions were decreased with increasing temperature, size of halide anion. Also solute-solvent interactions in the presence pyridinium ionic liquids are stronger than those of imidazolium ionic liquids The obtained results from spectroscopic reveal that λ_max of imidazolium based ionic liquids were red shifted in the presence of lactic acid and this behavior confirmed existence hydrogen bound between lactic acid and imidazolium based ionic liquids In the experiment, the researchers used many compounds, for example, 1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6Recommanded Product: 1-Butyl-4-methylpyridin-1-ium bromide).

1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6) 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). 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. Recommanded Product: 1-Butyl-4-methylpyridin-1-ium bromide

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Stepwise Formation of Molecular Rectangles of Half-Sandwich Rhodium and Ruthenium Complexes Containing Bridging Chloranilate Ligands was written by Han, Ying-Feng;Jia, Wei-Guo;Lin, Yue-Jian;Jin, Guo-Xin. And the article was included in Organometallics in 2008.Recommanded Product: 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole This article mentions the following:

Binuclear complexes [Cp^*₂Rh₂(μ-CA)Cl₂] (2a) and [(p-cymene)₂Ru₂(μ-CA)Cl₂] (2b) (CA = chloranilate) were obtained by the reactions of [Cp^*RhCl(μ-Cl)]₂ (1a) or [(p-cymene)RuCl(μ-Cl)]₂ (1b) with H₂CA in the presence of base, resp. Treatment of 2a or 2b with bidentate ligands (L) such as pyrazine, 4,4′-dipyridine (bpy), 2,5-bis(4-pyridyl)-1,3,5-oxadiazole (bpo), and E-1,2-bis(4-pyridyl)ethene (bpe) in the presence of AgOTf (OTf = CF₃SO₃) in CH₃OH gave the corresponding tetranuclear complexes, with the general formulas [Cp^*₄Rh₄(μ-CA)₂(μ-L)₂](OTf)₄ (3a–d) and [(p-cymene)₄Ru₄(μ-CA)₂(μ-L)₂](OTf)₄ (4a–d), resp. The mol. structures of [Cp^*₄Rh₄(μ-CA)₂(μ-bpy)₂](OTf)₄ (3b), [(p-cymene)₄Ru₄(μ-CA)₂(μ-bpy)₂](OTf)₄ (4b), and [(p-cymene)₄Ru₄(μ-CA)₂(μ-bpe)₂](OTf)₄ (4d) have been determined by single-crystal x-ray anal. and revealed that the metal centers were connected by pyridyl ligands and bis-bidentate chloranilate (CA) ligands to construct a rectangular cavity with different dimensions and strong π interactions between independent mols. to form rectangle channels in the solid state. In the experiment, the researchers used many compounds, for example, 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole (cas: 15420-02-7Recommanded Product: 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole).

2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole (cas: 15420-02-7) 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 derivatives are also useful as small-molecule α-helix mimetics that inhibit protein-protein interactions, as well as functionally selective GABA ligands.Recommanded Product: 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Polymeric reagents in organic chemistry. Catalytic activity of macromolecular matrixes with definite primary and secondary structures in polyphase reactions was written by Chiellini, Emo;Solaro, Roberto. And the article was included in Chimica e l’Industria (Milan, Italy) in 1978.COA of Formula: C10H16BrN This article mentions the following:

The alkylation of PhCH₂CN by alkyl bromides was catalyzed by quaternary ammonium salts prepared from poly[4-(chloromethyl)styrene]; trialkylamines, pyridines, and poly(vinylpyridines) also catalyzed the reaction. The above catalysts were also effective in the reaction of PhCHO with CHCl₃ to yield PhCH(OH)CO₂H and in the cycloaddition reaction of PhCH:CH₂ with :CCl₂(from CHCl₃). In the experiment, the researchers used many compounds, for example, 1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6COA of Formula: C10H16BrN).

1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6) 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. Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.COA of Formula: C10H16BrN

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Single-Step versus Stepwise Two-Electron Reduction of Polyarylpyridiniums: Insights from the Steric Switching of Redox Potential Compression was written by Fortage, Jerome;Peltier, Cyril;Perruchot, Christian;Takemoto, Yohei;Teki, Yoshio;Bedioui, Fethi;Marvaud, Valerie;Dupeyre, Gregory;Pospisil, Lubomir;Adamo, Carlo;Hromadova, Magdalena;Ciofini, Ilaria;Laine, Philippe P.;M. And the article was included in Journal of the American Chemical Society in 2012.Formula: C7H9NO This article mentions the following:

Contrary to 4,4′-dipyridinium (i.e., archetypal Me viologen), which is reduced by two single-electron transfers (stepwise reduction), the 4,1′-dipyridinium isomer (so-called “head-to-tail” isomer) undergoes two electron transfers at apparently the same potential (single-step reduction). A combined theor. and exptl. study has been undertaken to establish that the latter electrochem. behavior, also observed for other polyarylpyridinium electrophores, is due to potential compression originating in a large structural rearrangement. Three series of branched expanded pyridiniums (EPs) were prepared: N-aryl-2,4,6-triphenylpyridiniums (Ar-TP), N-aryl-2,3,4,5,6-pentaphenylpyridiniums (Ar-XP), and N-aryl-3,5-dimethyl-2,4,6-triphenylpyridinium (Ar-DMTP). The intramol. steric strain was tuned via N-pyridinio aryl group (Ar) Ph (Ph), 4-pyridyl (Py), and 4-pyridylium (qPy) and their bulky 3,5-di-Me counterparts, xylyl (Xy), lutidyl (Lu), and lutidylium (qLu), resp. Ferrocenyl subunits as internal redox references were covalently appended to representative electrophores in order to count the electrons involved in EP-centered reduction processes. Depending on the steric constraint around the N-pyridinio site, the two-electron reduction is single-step (Ar = Ph, Py, qPy) or stepwise (Ar = Xy, Lu, qLu). This steric switching of the potential compression is accurately accounted for by ab initio modeling (D. Functional Theory, DFT) that proposes a mechanism for pyramidalization of the N_pyridinio atom coupled with reduction When the hybridization change of this atom is hindered (Ar = Xy, Lu, qLu), the first reduction is a one-electron process. Theory also reveals that the single-step two-electron reduction involves couples of redox isomers (electromers) displaying both the axial geometry of native EPs and the pyramidalized geometry of doubly reduced EPs. This picture is confirmed by a combined UV-vis-NIR spectroelectrochem. and time-dependent DFT study: comparison of in situ spectroelectrochem. data with the calculated electronic transitions makes it possible to both evidence the distortion and identify the predicted electromers, which play decisive roles in the electron-transfer mechanism. Last, this mechanism is further supported by in-depth anal. of the electronic structures of electrophores in their various reduction states (including electromeric forms). In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Formula: C7H9NO).

3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8) belongs to pyridine derivatives. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. 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.Formula: C7H9NO

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Separation and identification by gas chromatography and gas chromatography-mass spectrometry of the nitrogen compounds from a deasphalted heavy oil. Evolution of their distribution after a catalytic hydrotreatment was written by Ignatiadis, I.;Schmitter, J. M.;Arpino, P.. And the article was included in Journal of Chromatography in 1985.Application of 644-98-4 This article mentions the following:

Basic and neutral N fractions were selectively isolated from a deasphalted heavy crude oil and were characterized by gas chromatog. and gas chromatog. mass spectrometry. Most chromatog. peaks were identified. Basic substances included C_5-10-alkylpyridines, C_1-9-alkylquinolines, and C_1-4-alkylbenzoquinolines; neutral fractions comprised C_1-4-alkylcarbazoles and C_1-4-alkylbenzocarbazoles. Only a few specific structures were isolated compared to the large total number of possible isomers. Pseudo-homologous series were recognized, a noticeable example being 8-isopropylalkylquinoline. These results were compared to the distribution of N substances from this sample after catalytic hydrotratment. Alkylpyridines totally disappeared, whereas C_1-7-alkylanilines were found. Identification of specific pseudo-homologous series of N substances in the hydrotreated sample confirm previous results on the resistance to hydrogenation of carbazoles and azaarenes bearing a Me substituent in α position to the N atom. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Application of 644-98-4).

2-Isopropylpyridine (cas: 644-98-4) 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.Application of 644-98-4

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

The role of ion/neutral complexes in the fragmentation of N-benzyl-(alkylpyridinium) ions was written by Kuck, Dietmar;Gruetzmacher, Hans-Friedrich;Barth, Dieter;Heitkamp, Sandra;Letzel, Matthias C.. And the article was included in International Journal of Mass Spectrometry in 2011.Computed Properties of C8H11N This article mentions the following:

N-Benzylpyridinium ions bearing an alkyl group at the pyridine nucleus were studied as potential precursors of gaseous ion/neutral complexes. The occurrence of I/N complexes [C₆H₅CH₂⁺ ··· alkylpyridine] was probed by the reactivity of the potential benzylic hydride donor sites present in the ortho-, meta- and para-alkyl groups (R = Me, Et, iso-Pr and benzyl). Collision-induced dissociation of the ions, carried out in an elec. ion cage mass spectrometer, revealed that hydride transfer strongly depends both on the energy requirements of the hydride transfer but also on the position of the hydride donor. Hydride transfer, giving rise to the loss of toluene, was found to occur exclusively with those N-benzylpyridinium ions which bear an iso-Pr or a benzyl substituent in the ortho position of the pyridine ring, thus reflecting the intermediacy of I/N complexes. All of the putative hydride donor alkyl groups were found to be non-reactive in the meta and para positions, as were Me and Et groups even in the ortho positions. D. functional calculations (B3LYP/6-311+G/3d,2p)//(B3LYP/6-31+G(d)) on the hydride-transfer and simple-cleavage channels were carried out to help rationalize these observations. The results suggest that the intra-complex hydride abstraction from the 3- and 4-isopropyl- and from the 3- and 4-benzylpyridine neutrals, although being thermodynamically favorable, is suppressed by substantial intra-complex rotational (or reorientation) barriers. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Computed Properties of C8H11N).

2-Isopropylpyridine (cas: 644-98-4) belongs to pyridine derivatives. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. 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.Computed Properties of C8H11N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem