Month: February 2023

catena-Poly[[silver(I)-μ-2,5-bis(4-pyridyl)-1,3,4-oxadiazole] nitrate], a one-dimensional coordination polymer exhibiting a double-chain supramolecular structure through hydrogen bonds was written by Guo, Ya Mei;Liu, He;Leng, Xue Bing. And the article was included in Acta Crystallographica, Section E: Structure Reports Online in 2003.Application In Synthesis of 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole This article mentions the following:

Crystals of the title compound are. Each Ag(I) center is coordinated by two N atoms of the pyridine rings of the bridging ligand 2,5-bis(4-pyridyl)-1,3,4-oxadiazole and one O donor of the nitrate anion, giving a trigonal coordination geometry. The ligands bridge the Ag(I) centers to form a 1-dimensional linear structure, which is further linked into a double-chain motif through intermol. C-H···O H bonds. In the experiment, the researchers used many compounds, for example, 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole (cas: 15420-02-7Application In Synthesis of 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.Application In Synthesis of 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Regio-Divergent C-H Alkynylation with Janus Directing Strategy via Ir(III) Catalysis was written by Li, Xianwei;Liang, Guangxin;Shi, Zhang-Jie. And the article was included in Chinese Journal of Chemistry in 2020.Computed Properties of C8H11N This article mentions the following:

The ‘one-to-two’ activation model was achieved by slight modification of simple and practical ketoxime and amide functionality. With judicious choice of directing groups, Csp³-H and Csp²-H bond alkynylation reaction and more significantly, dehydrogenative Csp³-H alkynylation were realized by enabling the regio-divergent late-stage modifications of pharmaceuticals. 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. 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. Computed Properties of C8H11N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Enantioselective modification of sulfonamides and sulfonamide-containing drugs via carbene organic catalysis was written by Song, Runjiang;Liu, Yingguo;Majhi, Pankaj Kumar;Ng, Pei Rou;Hao, Lin;Xu, Jun;Tian, Weiyi;Zhang, Long;Liu, Hongmei;Zhang, Xinglong;Chi, Yonggui Robin. And the article was included in Organic Chemistry Frontiers in 2021.SDS of cas: 1075-62-3 This article mentions the following:

A carbene-catalyzed method for highly enantioselective modification of sulfonamides to 3-(N-substituted)aminophthalides I [R = R¹ = H, Me; RR¹ = OCH₂O; R² = Ph, 4-ClC₆H₄, Bn, etc.; Ar = Ph, 4-O₂NC₆H₄] was disclosed. The reaction proceeded under mild conditions with broad substrate scope, wide functional group tolerance and good to excellent yields. When multiple sulfonamides or amines were present in the same mol., the reaction occurred in a highly chemo-selective manner. Application of this method allowed for selective modification of sulfonamide-containing drug mols. to form the corresponding phthalidyl derivatives, e.g., II as potential prodrugs. Exptl. observations and DFT calculations suggested that the reaction proceeded via a stepwise addition pathway, assisted by Li⁺ ions or protons. Non-covalent interactions, such as cation-π interactions, play important roles in enhancing the reactivity and controlling the enantioselectivity of the reaction. In the experiment, the researchers used many compounds, for example, N-(6-Aminopyridin-2-yl)acetamide (cas: 1075-62-3SDS of cas: 1075-62-3).

N-(6-Aminopyridin-2-yl)acetamide (cas: 1075-62-3) 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). 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.SDS of cas: 1075-62-3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

A Dichotomy in Cross-Coupling Site Selectivity in a Dihalogenated Heteroarene: Influence of Mononuclear Pd, Pd Clusters, and Pd Nanoparticles-the Case for Exploiting Pd Catalyst Speciation was written by Scott, Neil W. J.;Ford, Mark J.;Jeddi, Neda;Eyles, Anthony;Simon, Lauriane;Whitwood, Adrian C.;Tanner, Theo;Willans, Charlotte E.;Fairlamb, Ian J. S.. And the article was included in Journal of the American Chemical Society in 2021.Recommanded Product: 54151-74-5 This article mentions the following:

Mechanism, regioselectivity and kinetics of Suzuki-Miyaura coupling of 2,4-dibromopyridine with arylboronic acids catalyzed with a variety of palladium catalysts and additives, were explored. Site-selective dihalogenated heteroarene cross-coupling with organometallic reagents usually occurs at the halogen proximal to the heteroatom, enabled by intrinsic relative electrophilicity, particularly in strongly polarized systems. An archetypical example is the Suzuki-Miyaura cross-coupling (SMCC) of 2,4-dibromopyridine with organoboron species, which typically exhibit C2-arylation site-selectivity using mononuclear Pd (pre)catalysts. Given that Pd speciation, particularly aggregation, is known to lead to the formation of catalytically competent multinuclear Pd_n species, the influence of these species on cross-coupling site-selectivity remains largely unknown. Herein, we disclose that multinuclear Pd species, in the form of Pd₃-type clusters and nanoparticles, switch arylation site-selectivity from C2 to C4, in 2,4-dibromopyridine cross-couplings with both organoboronic acids (SMCC reactions) and Grignard reagents (Kumada-type reactions). The Pd/ligand ratio and the presence of suitable stabilizing salts were found to be critically important in switching the site-selectivity. More generally, this study provides exptl. evidence that aggregated Pd catalyst species not only are catalytically competent but also alter reaction outcomes through changes in product selectivity. In the experiment, the researchers used many compounds, for example, 2-Bromo-4-phenylpyridine (cas: 54151-74-5Recommanded Product: 54151-74-5).

2-Bromo-4-phenylpyridine (cas: 54151-74-5) 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: 54151-74-5

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Iodine(III)-Catalyzed Electrophilic Nitration of Phenols via Non-Bronsted Acidic NO₂⁺ Generation was written by Juarez-Ornelas, Kevin A.;Jimenez-Halla, J. Oscar C.;Kato, Terumasa;Solorio-Alvarado, Cesar R.;Maruoka, Keiji. And the article was included in Organic Letters in 2019.Electric Literature of C6H6N2O3 This article mentions the following:

The first catalytic procedure for the electrophilic nitration of phenols was developed using iodosylbenzene as an organocatalyst based on iodine(III) and aluminum nitrate as a nitro group source. This atom-economic protocol occurs under mild, non-Bronsted acidic and open-flask reaction conditions with a broad functional-group tolerance including several heterocycles. D. functional theory (DFT) calculations at the (SMD:MeCN)Mo8-HX/(LANLo8+f,6-311+G*) level indicated that the reaction proceeds through a cationic pathway that efficiently generates the NO₂⁺ ion, which is the nitrating species under neutral conditions. In the experiment, the researchers used many compounds, for example, 3-Hydroxy-6-methyl-2-nitropyridine (cas: 15128-90-2Electric Literature of C6H6N2O3).

3-Hydroxy-6-methyl-2-nitropyridine (cas: 15128-90-2) belongs to pyridine derivatives. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. 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 C6H6N2O3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Tuning the structure of pyridinolate-based functional ionic liquids for highly efficient SO₂ absorption was written by Cui, Guokai;Lyu, Shuzhen;Wang, Huiyong;Li, Zhiyong;Zhang, Ruina;Wang, Jianji. And the article was included in Fuel in 2021.Reference of 626-64-2 This article mentions the following:

A series of pyridinolate anion-functional ionic liquids (ILs) containing different kinds of cations were designed and prepared, including tri-n-hexyltetradecylphosphonium [P₆₆₆₁₄], tri-n-butylethylphosphonium [P₄₄₄₂], and 1,1,3,3-tetramethylguandinium [TMG] cations and pyridinolate [PyO] anions with different N positions. Densities and viscosities at different temperatures were measured because of their importance for the absorption of SO₂. Effect of different structures on the absorption of SO₂ was studied, including the type and the alkyl chain length of cations, and the N positions of [PyO] anions (2-, 3-, and 4-). Addnl., effects of SO₂ concentration and temperature for absorption were investigated. Especially, up to 6.00 and 2.53 mol SO₂ per mol IL could be obtained by [P₆₆₆₁₄][4-PyO] at 1 bar and 0.1 bar of SO₂, resp., when absorptions performed at 20°C. The results indicate that (1) the aprotic cations weakened the cation···anion interaction and resulted in the released active sites on the anions, and (2) N position has an influence on charge distribution of [PyO] anions and resulted in the tunable absorption of SO₂. Reversible SO₂ absorption and [P₆₆₆₁₄][4-PyO] regeneration could be performed several times without losing efficiency. Furthermore, the mechanism of absorption was studied through FT-IR and NMR methods and the results showed that the absorption of SO₂ by [P₆₆₆₁₄][4-PyO] includes physisorption and chemisorption. In the experiment, the researchers used many compounds, for example, Pyridin-4-ol (cas: 626-64-2Reference 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·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. Reference of 626-64-2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Low catalyst loadings for copper-catalyzed O-arylation of phenols and heteroaryl halides under mild conditions was written by Yong, Fui-Fong;Teo, Yong-Chua;Yan, Yaw-Kai;Chua, Guan-Leong. And the article was included in Synlett in 2012.Synthetic Route of C11H9NO This article mentions the following:

A practical and mild strategy has been developed for the cross-coupling of O-arylation of phenol with differently substituted aryl halides and heteroaryl iodides using low catalyst loading of copper iodide under low operating temperature in DMF with TMHD as the ligand and Cs₂CO₃ as the base. This method tolerates a variety of functional groups including sterically hindered phenols and heteroaryl iodides to afford products in good to excellent yields (up to 95%). In the experiment, the researchers used many compounds, for example, 2-Phenoxypyridine (cas: 4783-68-0Synthetic Route of C11H9NO).

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·mol−1 in pyridine vs. 150 kJ·mol−1 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.Synthetic Route of C11H9NO

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Synthesis of 3-hydroxy- and 3-carboxy-Δ²-isoxazoline amino acids and evaluation of their interaction with GABA receptors and transporters was written by Conti, Paola;De Amici, Marco;Pinto, Andrea;Tamborini, Lucia;Grazioso, Giovanni;Frolund, Bente;Nielsen, Birgitte;Thomsen, Christian;Ebert, Bjarke;De Micheli, Carlo. And the article was included in European Journal of Organic Chemistry in 2006.Computed Properties of C10H17NO2 This article mentions the following:

A series of 3-hydroxy- and 3-carboxy-Δ²-isoxazoline amino acids acids, structurally related to the GABA_A agonist THIP and to the GABA uptake inhibitors THPO, was prepared by means of synthetic strategies involving the 1,3-dipolar cycloaddition of nitrile oxides. All derivatives were submitted to a pharmacol. investigation at both GABA receptors and transporters. Unfortunately, all amino acids were devoid of activity except for a very low affinity at GABA_A receptors, displayed by compounds I and II. In the experiment, the researchers used many compounds, for example, tert-Butyl 5,6-dihydropyridine-1(2H)-carboxylate (cas: 85838-94-4Computed Properties of C10H17NO2).

tert-Butyl 5,6-dihydropyridine-1(2H)-carboxylate (cas: 85838-94-4) 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). Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Computed Properties of C10H17NO2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Photochemistry of pyridine N-oxides was written by Lohse, Christian;Hagedorn, Linda;Albini, Angelo;Fasani, Elisa. And the article was included in Tetrahedron in 1988.Application In Synthesis of 3,5-Dimethylpyridine 1-oxide This article mentions the following:

Photolysis of pyridine N-oxide in aqueous basic solution yields the anion of 5-hydroxypentadienenitrile. Kinetic data are obtained from flash photolytic measurements. The reaction is extended to twenty substituted pyridine N-oxides, including deuterated derivatives, as well as 10 other exptl. conditions (amines as the base in organic solvents). The results can be rationalized as involving primary photorearrangement to open-chain nitrene (I) (τ 62 ms in water) , which rearranges in low yield to 2-formylpyrrole or undergoes polymerization to tars. In the presence of bases, this intermediate is efficiently deprotonated to the anion of 5-hydroxypentadienenitrile (k = 690 M^-1s^-1 for the reaction of I with OH^–). The relation of this new rearrangement to other photoprocesses of heterocyclic N-oxides is discussed. In the experiment, the researchers used many compounds, for example, 3,5-Dimethylpyridine 1-oxide (cas: 3718-65-8Application In Synthesis of 3,5-Dimethylpyridine 1-oxide).

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. 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.Application In Synthesis of 3,5-Dimethylpyridine 1-oxide

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Alkaloids containing the α-pyridone ring was written by Orjales, A.;Ribas, I.;Varela, A.. And the article was included in Anales de Quimica (1968-1979) in 1972.Recommanded Product: 13472-81-6 This article mentions the following:

Cytisine and anagyrine form dications in 6N HCl that have an aromatic character similar to that of 2-ethoxypyridine. Their dihydrobromides were isolated and arise from a amide-zwitterion equilibrium Halogenation of cytisine occurs in the 3- and 5-positions. PCl5 or POCl3 treatment of cytisine or its dichloro derivative gave 2-(4-chloromethyl-3-piperidyl)-3,5,6-trichloropyridine, which was oxidized with KMnO4 to 3,5,6-trichloropicolinic acid. In the experiment, the researchers used many compounds, for example, 3,5-Dibromo-2-hydroxypyridine (cas: 13472-81-6Recommanded Product: 13472-81-6).

3,5-Dibromo-2-hydroxypyridine (cas: 13472-81-6) 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. 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: 13472-81-6

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem