Month: February 2023

Chain-walking cycloisomerization of 1,n-dienes catalyzed by pyridine-oxazoline palladium catalysts and its application to asymmetric synthesis was written by Hamasaki, Taro;Kakiuchi, Fumitoshi;Kochi, Takuya. And the article was included in Chemistry Letters in 2016.Quality Control of (S)-4-(tert-Butyl)-2-(4-(trifluoromethyl)pyridin-2-yl)-4,5-dihydrooxazole This article mentions the following:

Palladium catalysts possessing pyridine-oxazoline ligands, e.g., I, were found to catalyze the chain-walking cycloisomerization of 1,n-dienes, e.g., II, to form five-membered rings and were particularly effective for the reaction of 1,14-dienes, e.g., III. Asym. synthesis of cyclopentane derivatives was also achieved for the reaction of 1,n-dienes using chiral pyridine-oxazoline ligands. In the experiment, the researchers used many compounds, for example, (S)-4-(tert-Butyl)-2-(4-(trifluoromethyl)pyridin-2-yl)-4,5-dihydrooxazole (cas: 1257527-14-2Quality Control of (S)-4-(tert-Butyl)-2-(4-(trifluoromethyl)pyridin-2-yl)-4,5-dihydrooxazole).

(S)-4-(tert-Butyl)-2-(4-(trifluoromethyl)pyridin-2-yl)-4,5-dihydrooxazole (cas: 1257527-14-2) belongs to pyridine derivatives. Pyridine has a conjugated system of six 锜?electrons that are delocalized over the ring. The molecule is planar and, thus, follows the H鐪塩kel 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.Quality Control of (S)-4-(tert-Butyl)-2-(4-(trifluoromethyl)pyridin-2-yl)-4,5-dihydrooxazole

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Site-selective amide functionalization by catalytic azoline engrafting was written by Powell, Wyatt C.;Evenson, Garrett E.;Walczak, Maciej A.. And the article was included in ACS Catalysis in 2022.Application of 644-98-4 This article mentions the following:

Direct peptide and protein activation is a challenging transformation because of the stabilizing effect of the amide group. While enzymes can be considered as prototypical systems that have evolved to achieve high selectivity and specificity, small-mol. catalysts that functionalize the amide group may accommodate a much larger selection of substrates but currently remain scarce. Here, by combining the desired features from both catalytic regimes we designed an artificial cyclodehydratase, a catalytic system for the site-selective modification of peptides and natural products by engrafting heterocycles into their scaffolds. The catalytic system features a molybdenum(VI) center that was decorated with a sterically congested tripod ligand. The optimized catalyst can introduce azolines into small mols., natural products, and oligopeptides with high efficiency and minimal waste. We further demonstrate the utility of the new protocol in the direct functionalization of a single amide group in the presence of up to seven other chem. similar positions and in the direct conversion of these groups into amines and thioamides. This new mechanistic paradigm may address an unmet need for a general method for the selective and sustainable functionalization of peptides and natural products. 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’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. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Application of 644-98-4

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Mn(II) tags for DEER distance measurements in proteins via C-S attachment was written by Martorana, Andrea;Yang, Yin;Zhao, Yu;Li, Qing-Feng;Su, Xun-Cheng;Goldfarb, Daniella. And the article was included in Dalton Transactions in 2015.Category: pyridine-derivatives This article mentions the following:

Mn²⁺ chelating tags for Mn²⁺-Mn²⁺ distance measurements by pulse EPR spectroscopy were developed. They feature a stable C-S conjugation to the protein, high reactivity towards cysteine thiols and short and rigid linkers that can be used in distance measurements with high resolution under reductive conditions. Double electron-electron resonance measurements at 95 GHz on ubiquitin labeled with these tags showed the expected narrow distance distribution. In the experiment, the researchers used many compounds, for example, (4-Bromopyridin-2-yl)methanol (cas: 131747-45-0Category: pyridine-derivatives).

(4-Bromopyridin-2-yl)methanol (cas: 131747-45-0) 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, 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. Category: pyridine-derivatives

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Effects of Chain Length and Electrolyte on the Adsorption of n-Alkylpyridinium Bromide Surfactants at Sand-Water Interfaces was written by Paria, Santanu;Yuet, Pak K.. And the article was included in Industrial & Engineering Chemistry Research in 2006.Application of 104-73-4 This article mentions the following:

The kinetic and equilibrium studies of the adsorption of four cationic surfactants (pyridinium bromide) with different chain lengths (C₁₆, C₁₄, C₁₂, and C₁₀) onto sand are presented here. The adsorption and desorption behavior in the absence and presence of different electrolytes (NaCl, CaCl₂, and Na₂SO₄) are compared in batch and continuous column experiments The kinetic studies show that the rates of adsorption of pyridinium bromide surfactants on sand surfaces are very high (閳?0% of saturation adsorption occurs in 30 s) and are almost the same at low concentration (0.5 mM) for different chain lengths. The amount of surfactant adsorbed is enhanced by the presence of electrolyte because of a reduction in electrostatic repulsion among the headgroups, whereas the effect of the valence of coion does not appear to be important. Desorption studies based on column experiments show that a lower amount of surfactant is retained when eluted with electrolyte solution instead of pure water. In the experiment, the researchers used many compounds, for example, 1-Dodecylpyridin-1-ium bromide (cas: 104-73-4Application of 104-73-4).

1-Dodecylpyridin-1-ium bromide (cas: 104-73-4) 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. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Application of 104-73-4

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Orthogonal cross-coupling through intermolecular metathesis of unstrained C(aryl)-C(aryl) single bonds was written by Zhu, Jun;Zhang, Rui;Dong, Guangbin. And the article was included in Nature Chemistry in 2021.Recommanded Product: 4373-61-9 This article mentions the following:

Ruthenium-catalyzed reversible C-C single-bond metathesis reaction that allowed redox- and pH-neutral biaryl synthesis. Assisted by directing groups, unstrained homo-biaryl compounds underwent aryl exchanges to generate cross-biaryl products, catalyzed by a well-defined air-stable ruthenium(II) complex. Functional groups reactive under typical cross-coupling reactions, such as halogen, silyl and boronate moieties, were compatible under the metathesis conditions. Mechanistic studies disclosed an intriguing ‘olefin-metathesis-like’ pathway that involved an unexpected heptacoordinated, 18-electron closed-shell intermediate. The distinct reaction mode discovered here is expected to inspire the development of more general C-C single-bond metathesis and orthogonal cross-coupling reactions. 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 閳?8.7 鑴?10閳? cm3璺痬ol閳?.The molecular electric dipole moment is 2.2 debyes. The standard enthalpy of formation is 100.2 kJ璺痬ol閳? in the liquid phase and 140.4 kJ璺痬ol閳? in the gas phase. Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C閳ユ弻 in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Recommanded Product: 4373-61-9

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Quaternization at the picolinic carbon. Application to the synthesis of pyridylalkanecarboxylic acids was written by Pasquinet, Eric;Rocca, Patrick;Godard, Alain;Marsais, Francis;Queguiner, Guy. And the article was included in Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry in 1998.COA of Formula: C8H11N This article mentions the following:

This paper describes two different methodologies for the construction of a quaternary center at the picolinic site, and their application to the synthesis of pyridylalkanecarboxylic acids. The first one involves a one-pot acetylation-Michael addition procedure followed by an alkylative quaternization of the picolinic carbon. The second one is based on the deprotonation at the picolinic carbon of 2-(浼?浼?dialkyl)pyridines using the superbasic mixture BuLi-diisopropylamine-tert-BuOK (“KDA”). Both routes give very good yields. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4COA of Formula: C8H11N).

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 锜?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 锜?bonds. 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. COA of Formula: C8H11N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Structural Optimization of Indole Derivatives Acting at Colchicine Binding Site as Potential Anticancer Agents was written by Hwang, Dong-Jin;Wang, Jin;Li, Wei;Miller, Duane D.. And the article was included in ACS Medicinal Chemistry Letters in 2015.Application of 189230-41-9 This article mentions the following:

Diarylisoquinolines and (trimethoxyphenyl)(indolyl)imidazopyridines I (R = 2-indolyl, 3-indolyl, 4-indolyl, 6-indolyl, 7-indolyl), analogs of a previous trimethoxybenzoylphenylindole and I (R = 5-indolyl), were prepared as tubulin polymerization inhibitors acting at the colchicine binding site for potential use as antitumor agents with improved metabolic stabilities and cytotoxicities. I (R = 2-indolyl, 3-indolyl, 4-indolyl, 6-indolyl, 7-indolyl) inhibited tubulin polymerization with IC₅₀ values of 3 to 175 nM against a panel of human melanoma and prostate cancer cell lines. In particular, I (R = 6-indolyl) showed improved cytotoxic potency (average IC₅₀ of 9.75 nM vs 55.75 nM) and metabolic stability in human liver microsomes (half-life time was 56.3 min vs. 45.4 min) as compared to previously reported I (R = 5-indolyl). I (R = 6-indolyl) was effective against P-glycoprotein (P-gp) mediated multiple drug resistance (MDR) and taxol resistance. In the experiment, the researchers used many compounds, for example, 2-Bromopyridine-3,4-diamine (cas: 189230-41-9Application of 189230-41-9).

2-Bromopyridine-3,4-diamine (cas: 189230-41-9) 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.Application of 189230-41-9

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Simultaneous Estimation of Two Coupled Hydrogen Bond Geometries from Pairs of Entangled NMR Parameters: The Test Case of 4-Hydroxypyridine Anion was written by Tupikina, Elena Yu.;Sigalov, Mark V.;Tolstoy, Peter M.. And the article was included in Molecules in 2022.Application of 626-64-2 This article mentions the following:

The computational method for estimating the geometry of two coupled hydrogen bonds with geometries close to linear using a pair of spectral NMR parameters was proposed. The method was developed based on the quantum-chem. investigation of 61 complexes with two hydrogen bonds formed by oxygen and nitrogen atoms of the 4-hydroxypyridine anion with OH groups of substituted methanols. The main idea of the method is as follows: from the NMR chem. shifts of nuclei of atoms forming the 4-hydroxylpyridine anion, we select such pairs, whose values can be used for simultaneous determination of the geometry of two hydrogen bonds, despite the fact that every NMR parameter is sensitive to the geometry of each of the hydrogen bonds. For these parameters, two-dimensional maps of dependencies of NMR chem. shifts on interat. distances in two hydrogen bonds were constructed. It is shown that, in addition to chem. shifts of the nitrogen atom and quaternary carbon, which are exptl. difficult to obtain, chem. shifts of the carbons and protons of the CH groups can be used. The performance of the proposed method was evaluated computationally as well on three addnl. complexes with substituted alcs. It was found that, for all considered cases, hydrogen bond geometries estimated using two-dimensional correlations differed from those directly calculated by quantum-chem. methods by not more than 0.04 鑴? In the experiment, the researchers used many compounds, for example, Pyridin-4-ol (cas: 626-64-2Application of 626-64-2).

Pyridin-4-ol (cas: 626-64-2) belongs to pyridine derivatives. Pyridine has a dipole moment and a weaker resonant stabilization than benzene (resonance energy 117 kJ璺痬ol閳? in pyridine vs. 150 kJ璺痬ol閳? in benzene). Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Application of 626-64-2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem