Tag: 100-200

Palladium-Catalyzed Oxidative Olefination of Phenols Bearing Removable Directing Groups under Molecular Oxygen was written by Liu, Bin;Jiang, Huai-Zhi;Shi, Bing-Feng. And the article was included in Journal of Organic Chemistry in 2014.SDS of cas: 4783-68-0 This article mentions the following:

An efficient Pd(II)-catalyzed oxidative olefination of phenols bearing removable directing groups with mol. oxygen as the sole oxidant has been developed. E.g., in presence of Pd(OAc)₂ under atm. O₂, oxidative olefination of 2-phenoxypyridine with Et acrylate gave 73% (E)-I and (E,E)-II (13.6:1). This reaction protocol provides an efficient and robust synthetic tool for the synthesis of o-alkenyl phenols under mild conditions. In the experiment, the researchers used many compounds, for example, 2-Phenoxypyridine (cas: 4783-68-0SDS of cas: 4783-68-0).

2-Phenoxypyridine (cas: 4783-68-0) 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. 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: 4783-68-0

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Oxidative chlorination of 4-pentenols and other functionalized hydrocarbons was written by Bruecher, Oliver;Hartung, Jens. And the article was included in Tetrahedron in 2014.Name: Pyridinehydrochloride This article mentions the following:

Substituted 4-pentenols undergo regio- and stereoselective chlorocyclization, when treated in solutions of di-Me carbonate with chloride, a terminal oxidant, and a buffered proton source. Effective oxidants for liberating chlorine-like reactivity from chloride in the temperature range between 20 and 40 °C are tert-Bu hydroperoxide, activated by a titanium(IV) or a molybdenum(VI) ONO-chelate complex, and potassium monoperoxysulfate from the ternary salt 2KHSO₅·KHSO₄·K₂SO₄ (oxone). Substituents in the flexible part of the alkenol direct oxidative chlorocyclization 2,5-trans- and 2,4-cis-selectively. (E)-Configuration at the alkene translates anti-specifically into relative configuration of substituents at the β-chlorohydrin ether entity. A Ph group bound to the terminal alkene carbon alters the inherent 5-exo-specificity for chlorocyclization of terminal 4-pentenols toward 6-endo-selectivity, as exemplified by synthesis of trans-3-chloro-2-phenyltetrahydropyran from (E)-5-phenyl-4-penten-1-ol in up to 74% yield. Competition kinetics show that 5-exo-chlorocyclization of 1-phenyl-4-penten-1-ol occurs at 40 °C 600 times faster than electrophilic aromatic chlorosubstitution of anisole. Prenyl-type alkenols undergo allylic chlorination with an ene-type selectivity, as exemplified in synthesis of a building block for the fragrance component rose oxide from citronellol. In the experiment, the researchers used many compounds, for example, Pyridinehydrochloride (cas: 628-13-7Name: Pyridinehydrochloride).

Pyridinehydrochloride (cas: 628-13-7) belongs to pyridine derivatives. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Name: Pyridinehydrochloride

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Thermodynamics of protonation of pyridine N-oxide and its methyl-substituted derivatives in aqueous media was written by Klofutar, C.;Paljk, S.;Kremser, D.. And the article was included in Spectrochimica Acta, Part A: Molecular and Biomolecular Spectroscopy in 1973.Safety of 3,5-Dimethylpyridine 1-oxide This article mentions the following:

Thermodn. protonation constants of pyridine N-oxide and its Me derivatives are measured spectrophotometrically from 20-60°. The substituent effect on the free energy of proton ionization is additive, and an approx. linear relation exists between the pKa values of pyridine N-oxides and those of the pyridines. The changes of reaction enthalpy and entropy are discussed in terms of internal and external contributions of thermodn. functions. 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. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Safety of 3,5-Dimethylpyridine 1-oxide

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Reaction of aromatic N-oxides with dipolarophiles. XII. Stereoselective exo cycloaddition of 3,5-lutidine N-oxide with N-substituted maleimides and a frontier molecular orbital and mechanistic study was written by Hisano, Takuzo;Harano, Kazunobu;Matsuoka, Toshikazu;Yamada, Hirotoshi;Kurihara, Masahiko. And the article was included in Chemical & Pharmaceutical Bulletin in 1987.Reference of 3718-65-8 This article mentions the following:

Pericyclic reactions of 3,5-lutidine N-oxide with N-phenylmaleimides were investigated. The primary cycloadducts are thermally labile and undergo 1,5-sigmatropic rearrangement to give the 2,3-dihydropyridine derivatives The proton NMR structural assignment of the 1,5-sigmatropy products implies that the primary cycloaddition proceeds through an exo transition state. The reaction behavior is discussed in terms of frontier MO theory, based on MINDO/3 and CNDO/2 calculations and kinetic data. The reaction falls into the category of a normal-type cycloaddition and the exo cycloaddition is brought about by the unfavorable secondary orbital interaction. In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Reference of 3718-65-8).

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. Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Reference of 3718-65-8

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

The selenium dioxide oxidation of 2,3- and 3,4-dimethylpyridines was written by Dunn, A. D.. And the article was included in Organic Preparations and Procedures International in 1999.Application In Synthesis of Methyl 3-methylpicolinate This article mentions the following:

The SeO₂ oxidation of 2,3-dimethylpyridine gave 3-methyl-2-pyridinecarboxaldehyde and 3-methyl-2-pyridinecarboxylic acid, isolated as its Me ester. The aldehyde was converted to its oxime which was dehydrated to the carbonitrile. 3,4-Dimethylpyridine similarly gave 3-methylisonicotinaldehyde and the acid and nitrile. In the experiment, the researchers used many compounds, for example, Methyl 3-methylpicolinate (cas: 59718-84-2Application In Synthesis of Methyl 3-methylpicolinate).

Methyl 3-methylpicolinate (cas: 59718-84-2) 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.Application In Synthesis of Methyl 3-methylpicolinate

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Comparative basicities of substituted pyridines and electronegativity series in pyridines was written by Grandberg, I. I.;Faizova, G. K.;Kost, A. N.. And the article was included in Khimiya Geterotsiklicheskikh Soedinenii in 1966.Reference of 4783-68-0 This article mentions the following:

From a comparison of the pKa values of pyridine and 74 substituted pyridines (I), the effects of substituent groups on basicity were distinguished. For 2-substituents the order of decreasing basicity is: Cl > Br ≥ I > PhO > Ac > MeO > m-O2NC6H4 > p-O2NC6H4 > CHO > 2,4-(O2N)2C6H3CH2 > Ph > CH(OH)Ph > CPh:CH2 > vinyl > H > benzyl > 1-cyclohexen-1-yl ≥ CMe:CH2 > CH2OH > Me2CHCH2 ≥ HOCH2CH2 > iso-Pr ≥ Me. For 3-substituents the corresponding order is: NO2 > Cl > Br > CO2Et > Ac > CHO > CCH > Ph > MeO > vinyl > H > OH > Me ≥ Et ≥ iso-Pr ≥ Me2CHCH2. For 4-substituents the order is: NO2 > Cl > CO2Et > Ac > CCPh > CHO > p-O2NC6H4 > m-O2NC6H4 > CH:CHC6H4NO2-p > H > vinyl > benzyl > Ph > CH:CHC6H4Cl-p > CH:CHPh > CH:CHC6H4Me-p > iso-Bu > CH:CHC6H4Pr-iso-p ≥ Me ≥ Et ≥ iso-Pr ≥ CH:CHC6H4OMe-p > MeO. Some data are given also for pyridine oxides. The results were interpreted in terms of inductive and mesomeric effects. The latter were found to be more important at the 4-position than at the 2-position. Hydroxy substitution in the 3-position showed a pronounced mesomeric effect. Hydroxy substitution in the 2- and 4-positions was not studied because of pyridone tautomerism. In the experiment, the researchers used many compounds, for example, 2-Phenoxypyridine (cas: 4783-68-0Reference of 4783-68-0).

2-Phenoxypyridine (cas: 4783-68-0) 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. Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Reference of 4783-68-0

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Rare-Earth-Catalyzed C-H Bond Addition of Pyridines to Olefins was written by Guan, Bing-Tao;Hou, Zhaomin. And the article was included in Journal of the American Chemical Society in 2011.Electric Literature of C8H11N This article mentions the following:

An efficient and general protocol for the ortho-alkylation of pyridines via C-H addition to olefins has been developed, using cationic half-sandwich rare-earth catalysts, which provides an atom-economical method for the synthesis of alkylated pyridine derivatives A wide range of pyridine and olefin substrates including α-olefins, styrenes, and conjugated dienes are compatible with the catalysts. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Electric Literature of C8H11N).

2-Isopropylpyridine (cas: 644-98-4) 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.Electric Literature of C8H11N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Enantioselective synthesis of tunable chiral pyridine-aminophosphine ligands and their applications in asymmetric hydrogenation was written by Liu, Youran;Chen, Fei;He, Yan-Mei;Li, Chenghao;Fan, Qing-Hua. And the article was included in Organic & Biomolecular Chemistry in 2019.Related Products of 644-98-4 This article mentions the following:

A small library of tunable chiral pyridine-aminophosphine ligands were enantioselectively synthesized based on chiral 2-(pyridin-2-yl)-substituted 1,2,3,4-tetrahydroquinoline scaffolds, which were obtained in high yields and with excellent enantioselectivities via Ru-catalyzed asym. hydrogenation of 2-(pyridin-2-yl)quinolines. The protocol features a wide substrate scope and mild reaction conditions, enabling scalable synthesis. These chiral P,N ligands were successfully applied in the Ir-catalyzed asym. hydrogenation of benchmark olefins and challenging seven-membered cyclic imines including benzazepines and benzodiazepines. Excellent enantio- and diastereoselectivity (up to 99% ee and >20 : 1 dr), and/or unprecedented chemoselectivity were obtained in the asym. hydrogenation of 2,4-diaryl-3H-benzo[b]azepines and 2,4-diaryl-3H-benzo[b][1,4]diazepines. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Related Products of 644-98-4).

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

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Determination of a new scale of ortho-steric parameters S⁰ from N-methylation of pyridines was written by Berg, Ulf;Gallo, Roger;Klatte, Gerd;Metzger, Jacques. And the article was included in Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry (1972-1999) in 1980.Quality Control of 2-Isopropylpyridine This article mentions the following:

The kinetics of quaternization by MeI of 33 substituted pyridines, e.g. 2-ethylpyridine, were measured in MeCN at 30°. The relative rate constants obtained were similar to those observed in other polar aprotic solvents. The magnitude of steric effects observed for all ortho-substituents were estimated from the Broensted plot. A scale of ortho-steric parameters (S⁰) was proposed. No correlation was observed between S⁰ and the electronic effect of substituents. S⁰ Is not solvent dependent. The relative S⁰ values agree with other exptl. values of the steric size of the substituents. The S⁰ parameters are discussed in terms of substituent structure relative to the Taft-Kutter-Hansch E_s and Charton ν parameters. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Quality Control of 2-Isopropylpyridine).

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

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Carboxylation of 2-hydroxypicolines was written by Weglinski, Zbigniew;Talik, Tadeusz. And the article was included in Roczniki Chemii in 1977.Recommanded Product: 65169-38-2 This article mentions the following:

Treatment of a mixture of 2-hydroxy-3-methylpyridine (I) and anhydrous K₂CO₃ with 55 atm CO₂ at 220° for 9 h gave 87% 2-hydroxy-3-methyl-5-pyridinecarboxylic acid (II). Carboxylation of the Na and K salts of I gave 49.5 and 53% II, resp. Similarly, 2-hydroxy-5-methyl-, 2-hydroxy-6-methyl-, and 2-hydroxy-4-methylpyridine gave 2-hydroxy-5-methyl-3-pyridinecarboxylic acid, 2-hydroxy-6-methyl-3-pyridinecarboxylic acid, and 2-hydroxy-4-methyl-5-pyridinecarboxylic acid, resp. The isomeric hydroxymethylpyridinecarboxylic acids were also prepared by hydrolysis of the corresponding isomeric chlorocyanopicolines. The latter were obtained from isomeric aminopicolines by successive nitration, hydroxylation, chlorination, reduction, and Sandmeyer cyanation. In the experiment, the researchers used many compounds, for example, 2-Chloro-4-methylpyridine-3-carbonitrile (cas: 65169-38-2Recommanded Product: 65169-38-2).

2-Chloro-4-methylpyridine-3-carbonitrile (cas: 65169-38-2) 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, 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. Recommanded Product: 65169-38-2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem