Day: February 13, 2023

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.Recommanded Product: 2-Phenoxypyridine 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鎺? 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 璋?parameters. In the experiment, the researchers used many compounds, for example, 2-Phenoxypyridine (cas: 4783-68-0Recommanded Product: 2-Phenoxypyridine).

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

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

A simple one-pot synthesis of benzoxazine- 2,4-diones and benzothiazine-2,4-diones was written by Zhu, Xiaoxiang;Yu, Qian-Sheng;Greig, Nigel H.;Flippen-Anderson, Judith L.;Brossi, Arnold. And the article was included in Heterocycles in 2003.Application of 28020-37-3 This article mentions the following:

A simple and efficient procedure has been developed for a one-pot synthesis of substituted benzoxazine-2,4-diones and benzothiazine-2,4-diones directly from salicylic acid (or thiosalicylic acid) and amines. The reaction of [2-(chlorocarbonyl)phenyl]carbonic acid Me ester with 3,4-dimethoxybenzeneethanamine gave 2-(acetyloxy)-N-[2-(3,4-dimethoxyphenyl)ethyl]benzamide. Deprotection of this gave 2-hydroxy-N-[2-(3,4-dimethoxyphenyl)ethyl]benzamide and sequential cyclocondensation with carbonochloridic acid Et ester gave 3-[2-(3,4-dimethoxyphenyl)ethyl]-2H-1,3-benzoxazine-2,4(3H)-dione (I). A similar reaction sequence starting from 2-mercaptobenzoic acid gave 3-(phenylmethyl)-2H-1,3-benzothiazine-2,4(3H)-dione (II). In the experiment, the researchers used many compounds, for example, 3-Amino-2,6-dimethoxypyridine (cas: 28020-37-3Application of 28020-37-3).

3-Amino-2,6-dimethoxypyridine (cas: 28020-37-3) 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). Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Application of 28020-37-3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Highly Regio- and Chemoselective Oxidative C-H/C-H Cross-Couplings of Anilines and Phenols Enabled by a Co-Oxidant-Free Rh(I)/Zn(NTf₂)₂/Air Catalytic System was written by Zhang, Luoqiang;Wang, Yanbing;Shi, Yang;Wu, Yimin;Lan, Jingbo;Ma, Weixin;You, Jingsong. And the article was included in ACS Catalysis in 2019.Electric Literature of C11H9NO This article mentions the following:

An urgent yet challenging task is to overcome the limitations in substrate scope and regio- and chemoselectivity in the oxidative couplings between two arenes for the construction of unsym. 2,2′-difunctional biaryls with diverse application requirements. In this work, a co-oxidant-free Rh(I)/Zn(NTf₂)₂/air catalytic system has been developed for dual chelation-assisted oxidative C-H/C-H cross-couplings between two anilines, between two phenols, and between phenols and anilines, which enables rapid assembly of rich libraries of 2,2′-bianilines, 2,2′-biphenols, and 2′-aminobiphenyl-2-ols. This protocol features air as the sole oxidant, complete regioselectivity, high chemoselectivity, low molar ratio of substrates (even 1:1), convenient operation, and scale-up synthesis. The established catalytic system is tolerant of the substrates having both electron-donating and electron-withdrawing substituents at different positions of the aryl ring. This work further discloses that the chemoselectivity of cross-coupling over homocoupling mainly relies on a suitable combination of two directing groups (i.e., a pair of strongly and weakly coordinating directing groups) rather than the electronically distinct properties between two substrates, which provides an inspiration for designing the matching directing group pair for the dual chelation-assisted oxidative Ar-H/Ar-H cross-couplings. Thus, this strategy allows the highly chemoselective cross-coupling between electronically similar coupling partners, which represents a challenging task in the oxidative Ar-H/Ar-H cross-coupling reactions. In the experiment, the researchers used many compounds, for example, 2-Phenoxypyridine (cas: 4783-68-0Electric Literature of C11H9NO).

2-Phenoxypyridine (cas: 4783-68-0) 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. Electric Literature of C11H9NO

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Ruthenium(II)-catalyzed ortho-C-H arylation of diverse N-heterocycles with aryl silanes by exploiting solvent-controlled N-coordination was written by Nareddy, Pradeep;Jordan, Frank;Szostak, Michal. And the article was included in Organic & Biomolecular Chemistry in 2017.Formula: C12H11N This article mentions the following:

The first method for the direct, regioselective Ru(II)-catalyzed oxidative arylation of C-H bonds in diverse N-heterocycles, e.g., 1-phenyl-1H-pyrazole with aryl silanes 4-RC₆H₄Si(OMe)₃ (R = H, Me, Cl, etc.) by exploiting solvent-controlled N-coordination has been reported. The reaction takes advantage of the attractive features of organosilanes as coupling partners, providing proof of concept for N-directed Ru(II)-catalyzed C-H arylation. This novel, operationally-simple and versatile protocol utilizes the Ru(II)/CuF₂ reagent system in which CuF₂ serves as a dual activator/oxidant in non-coordinating solvents to accommodate for ligand N-coordination. This first Ru(II)-catalyzed N-directed Hiyama C-H arylation offers broad implications to achieve numerous C-H bond functionalizations by versatile ruthenium(II) catalysis manifold. In the experiment, the researchers used many compounds, for example, 2-(m-Tolyl)pyridine (cas: 4373-61-9Formula: C12H11N).

2-(m-Tolyl)pyridine (cas: 4373-61-9) 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. Formula: C12H11N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Rh(III)-Catalyzed C-C coupling of unactivated C(sp³)-H bonds with iodonium ylides for accessing all-carbon quaternary centers was written by Xie, Pengfei;Gao, Huixing;Li, Xingwei;Jiang, Yuqin;Liu, Bingxian. And the article was included in Organic Chemistry Frontiers in 2022.Formula: C8H11N This article mentions the following:

Rhodium-catalyzed inert C(sp³)-H activation/carbene insertion, which enables the construction of all-carbon quaternary centers, has been realized. Iodonium ylides are used as C1 synthons for efficient C-C bond formation with PhI being the only byproduct. A rhodacycle has been synthesized and proved to be the active intermediate. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Formula: 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 groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Formula: C8H11N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Structure-Activity Relationships and X-ray Structures Describing the Selectivity of Aminopyrazole Inhibitors for c-Jun N-terminal Kinase 3 (JNK3) over p38 was written by Kamenecka, Ted;Habel, Jeff;Duckett, Derek;Chen, Weimin;Ling, Yuan Yuan;Frackowiak, Bozena;Jiang, Rong;Shin, Youseung;Song, Xinyi;LoGrasso, Philip. And the article was included in Journal of Biological Chemistry in 2009.HPLC of Formula: 89978-52-9 This article mentions the following:

C-Jun N-terminal kinase 3浼? (JNK3浼?) is a mitogen-activated protein kinase family member expressed primarily in the brain that phosphorylates protein transcription factors, including c-Jun and activating transcription factor-2 (ATF-2) upon activation by a variety of stress-based stimuli. In this study, we set out to design JNK3-selective inhibitors that had >1000-fold selectivity over p38, another closely related mitogen-activated protein kinase family member. To do this we employed traditional medicinal chem. principles coupled with structure-based drug design. Inhibitors from the aminopyrazole class, such as SR-3576, were found to be very potent JNK3 inhibitors (IC₅₀ = 7 nM) with >2800-fold selectivity over p38 (p38 IC₅₀ > 20 娓璏) and had cell-based potency of 閳? 娓璏. In contrast, indazole-based inhibitors exemplified by SR-3737 were potent inhibitors of both JNK3 (IC₅₀ = 12 nM) and p38 (IC₅₀ = 3 nM). These selectivity differences between the indazole class and the aminopyrazole class came despite nearly identical binding (root mean square deviation = 0.33 鑴? of these two compound classes to JNK3. The structural features within the compounds giving rise to the selectivity in the aminopyrazole class include the highly planar nature of the pyrazole, N-linked Ph structures, which better occupied the smaller active site of JNK3 compared with the larger active site of p38. In the experiment, the researchers used many compounds, for example, Ethyl 2-bromoisonicotinate (cas: 89978-52-9HPLC of Formula: 89978-52-9).

Ethyl 2-bromoisonicotinate (cas: 89978-52-9) 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. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.HPLC of Formula: 89978-52-9

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Rhodium(I)-catalysed decarbonylative direct C-H vinylation and dienylation of arenes was written by Xu, Jianbin;Chen, Changjun;Zhao, Haoqiang;Xu, Conghui;Pan, Yixiao;Xu, Xin;Li, Huanrong;Xu, Lijin;Fan, Baomin. And the article was included in Organic Chemistry Frontiers in 2018.Formula: C12H11N This article mentions the following:

Rh(I)-catalyzed decarbonylative direct C-H bond vinylation and dienylation of arenes with readily available acrylic acid and (E)-penta-2,4-dienoic acid under chelation assistance were developed for the first time. A significant effect of the ligand on the reactivity was observed with the bidentate phosphine ligand being optimal. This protocol was efficient under oxidant-free conditions to access synthetically valuable styrenes and 1-aryl-1,3-butadienes in high yields with a broad substrate scope and good functionality tolerance. In the experiment, the researchers used many compounds, for example, 2-(m-Tolyl)pyridine (cas: 4373-61-9Formula: 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.Formula: C12H11N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Reaction of 2-pyridones with benzyne was written by Bauer, Ludwig;Bell, Charles Leighton;Wright, George Edward. And the article was included in Journal of Heterocyclic Chemistry in 1966.Recommanded Product: 4783-68-0 This article mentions the following:

When 1-methyl-2-pyridone (I) was allowed to react with diazotized anthranilic acid (II) under conditions which generate benzyne (Friedman and Logullo, CA 59, 1556a), the adduct (III) was obtained in 10% yield, with acridone as a by product, which also forms from II under identical conditions even in the absence of I. On pyrolysis at 200鎺? III forms naphthalene. When benzyne was generated from PhCl and NaNH2 (Leake and Levine, CA 53, 16048f), the reaction with I gave 1-methyl-3-phenyl-2-pyridone in 5.4% yield, with 1,1′-dimethyl-2,2′-bipyridine-6,6′-dioneas by-product [which was also synthesized from 2,2′-bipyridine by quaternizing it with Me2SO4 to the bis(methosulfate), followed by the Decker oxidation with K3Fe(CN)6]. It also forms in small amounts in the reaction of I with NaNH2 in liquid NH3 in the absence of PhCl. In liquid NH3, ring opening of I was observed to give MeNHCH:CHCH:CHCONH2 in 6% yield. In the reaction of 2-pyridone with benzyne (from II) no Diels-Alder adduct could be isolated, the products found being 2-phenoxypyridine (3.9%), 1-phenyl-2-pyridone, and a little acridone. In the experiment, the researchers used many compounds, for example, 2-Phenoxypyridine (cas: 4783-68-0Recommanded Product: 4783-68-0).

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

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Decarboxylative Arylation of Pyridine 1-Oxides and Anilides with Benzoic Acid via Palladium-Catalyzed C-H Functionalization was written by Dabiri, Minoo;Alavioon, Seyed Iman;Movahed, Siyavash Kazemi. And the article was included in European Journal of Organic Chemistry in 2019.Product Details of 3718-65-8 This article mentions the following:

A novel method for the palladium-catalyzed decarboxylative ortho C-H bond arylation of pyridine 1-oxides I [R¹ = H, 3-Cl, 3-C(O)OCH₂CH₃, 4-CN, etc.] and anilides R²NHC(O)R³ [R² = C₆H₅, 4-BrC₆H₄, 3,4-(H₃CO)₂C₆H₃, etc.; R³ = C(CH₃)₃, C₆H₅] with benzoic acids R⁴C₆H₄C(O)OH [R⁴ = 4-CF₃, 4-F, 4-NO₂, 2-Br, 3-CH₃, etc.] as aryl sources is described. The established methodol. provides a direct approach for the synthesis of 2-arylpyridine 1-oxides II and 2-aryl anilides 4-R⁵-5-R⁶-2-(R⁴C₆H₄)C₆H₂NHC(O)R³ (R⁵ = H, Br, Me, CF₃, F, Cl, MeO; R⁶ = H, Cl, Me, MeO) in good isolated yields. In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Product Details of 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 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. Pyridine derivatives are also useful as small-molecule 浼?helix mimetics that inhibit protein-protein interactions, as well as functionally selective GABA ligands.Product Details of 3718-65-8

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem