Tag: 100-200

Pentamethylcyclopentadienyl rhodium(III)-chiral disulfonate hybrid catalysis for enantioselective C-H bond functionalization was written by Satake, Shun;Kurihara, Takumaru;Nishikawa, Keisuke;Mochizuki, Takuya;Hatano, Manabu;Ishihara, Kazuaki;Yoshino, Tatsuhiko;Matsunaga, Shigeki. And the article was included in Nature Catalysis in 2018.Application of 4373-61-9 This article mentions the following:

Here, a hybrid strategy for inducing chirality was reported for the synthesis of [(pyridin-2-yl)phenyl]alkanones I (R¹ = H, 4-Me, 5-Me; R² = H, 4-Me, 4-Cl, etc.; R³ = Me, PhCH₂CH₂; R⁴ = Me, Et, n-Bu, etc.) via pentamethylcyclopentadienyl rhodium(III)-chiral disulfonate hybrid catalyzed C-H activation and subsequent conjugate addition of 2-phenylpyridine derivatives to α,β-unsaturated ketones in good yields and enantioselectivity (enantiomeric ratio up to 95:5). In addition to 2-phenylpyridines, the conjugate addition of 6-arylpurines proceeded with an enantiomeric ratio of up to 91:9 using [Cp*RhL_N][(R)-SPISate] to afford [(9H-purin-6-yl)phenyl]alkanones II (R⁵ = i-Pr, PhCH₂; R⁶ = H, Me, OMe, t-Bu). The results demonstrated that a chiral organic anion could efficiently control the enantioselectivity of Cp*Rh(III)-catalyzed C-H bond functionalization without a chiral Cp^x ligand. In the experiment, the researchers used many compounds, for example, 2-(m-Tolyl)pyridine (cas: 4373-61-9Application of 4373-61-9).

2-(m-Tolyl)pyridine (cas: 4373-61-9) 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. 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.Application of 4373-61-9

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

The first (tripyrrinato)nickel(II) complexes, TrpyNiX with X = Cl, Br, I: synthesis, structures and solvent coordination was written by Broering, Martin;Prikhodovski, Serguei;Brandt, Carsten D.. And the article was included in Journal of the Chemical Society, Dalton Transactions in 2002.Safety of 3,5-Dimethylpyridine 1-oxide This article mentions the following:

A first series of Ni(II) complexes I (X = Cl, L = H₂O; X = Br, I, X = null) of the new tripyrrolic ligand 2,15-dimethyl-3,4,8,9,13,14-hexaethyltripyrrin was prepared and characterized by spectroscopic and structural means. The coordination geometry found for the four-coordinate, paramagnetic bromo- and iodo-derivatives in the solid state can best be described as distorted trigonal-bipyramidal with one ligand missing in the trigonal plane. For the chloro derivative, this empty site is occupied in the crystal by a H₂O ligand. As ¹H NMR studies on the paramagnetic TrpyNiCl reveal an equilibrium exists between the four- and five-coordinate form with solvent, but not a six-coordinate form, and for pyridine-N-oxide as the fifth ligand, thermodn. data of the ligand association could be obtained by a temperature dependent NMR titration study. In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Safety of 3,5-Dimethylpyridine 1-oxide).

3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8) 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.Safety of 3,5-Dimethylpyridine 1-oxide

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Reaction of Pyridine-N-Oxides with Tertiary sp²-N-Nucleophiles: An Efficient Synthesis of Precursors for N-(Pyrid-2-yl)-Substituted N-Heterocyclic Carbenes was written by Bugaenko, Dmitry I.;Yurovskaya, Marina A.;Karchava, Alexander V.. And the article was included in Advanced Synthesis & Catalysis in 2020.Related Products of 59718-84-2 This article mentions the following:

N-(Pyrid-2-yl)-substituted azolium and pyridinium salts, precursors for hybrid NHC-containing ligands, were obtained with excellent regioselectivity, employing a deoxygenative CH-functionalization of pyridine-N-oxides with substituted imidazoles, thiazoles, and pyridine. Unlike the traditional S_NAr-based methods, this approach provides high yields for substrates bearing substituents of different electronic nature. The utility of azolium and pyridinium salts thus prepared was also highlighted by the synthesis of pyridyl-substituted imidazolyl-2-thione, benzodiazepine as well as 2-aminopyridines. In the experiment, the researchers used many compounds, for example, Methyl 3-methylpicolinate (cas: 59718-84-2Related Products of 59718-84-2).

Methyl 3-methylpicolinate (cas: 59718-84-2) 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. Pyridine, its benzo and pyridine-based compounds play diverse roles in organic chemistry. Pyridine-based materials are valued for their optical and physical properties as well as their medical potential. Related Products of 59718-84-2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Mild C-H/C-C Activation by Z-Selective Cobalt Catalysis was written by Zell, Daniel;Bu, Qingqing;Feldt, Milica;Ackermann, Lutz. And the article was included in Angewandte Chemie, International Edition in 2016.Category: pyridine-derivatives This article mentions the following:

Cationic cobalt complexes enable unprecedented cobalt-catalyzed C-H/C-C functionalizations with unique selectivity features. The versatile cobalt catalyst proved broadly applicable, enabled efficient C-H/C-C cleavage at room temperature, and delivered Z-alkenes, e.g., I, with excellent diastereocontrol. In the experiment, the researchers used many compounds, for example, 2-(m-Tolyl)pyridine (cas: 4373-61-9Category: pyridine-derivatives).

2-(m-Tolyl)pyridine (cas: 4373-61-9) 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. 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. Category: pyridine-derivatives

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Rhodium-Catalyzed Selective Mono- and Diamination of Arenes with Single Directing Site “On Water” was written by Ali, Ashif Md;Yao, Xiayin;Li, Guigen;Lu, Hongjian. And the article was included in Organic Letters in 2016.Recommanded Product: 4373-61-9 This article mentions the following:

A Rh(III)-catalyzed selective C-H amination of 2-phenylpyridine derivatives is reported. With pyridine as a directing group, the reaction has high mono- or diamination selectivity, and a wide range of effective substrates, including electron-deficient and -rich aryl azides. Water helps to promote C-H activation, and the concept of a water-promoted rollover mechanism is postulated for the diamination step. The reactions were conducted using a Schlenk flask and proceeded smoothly “on water” under atm. conditions with nitrogen gas as the only byproduct. In the experiment, the researchers used many compounds, for example, 2-(m-Tolyl)pyridine (cas: 4373-61-9Recommanded Product: 4373-61-9).

2-(m-Tolyl)pyridine (cas: 4373-61-9) 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. 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.Recommanded Product: 4373-61-9

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

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

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

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

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