Day: February 7, 2023

Functional Supramolecular Polypeptides Involving π-π Stacking and Strong Hydrogen-Bonding Interactions: A Conformation Study toward Carbon Nanotubes (CNTs) Dispersion was written by Huang, Cheng-Wei;Mohamed, Mohamed Gamal;Zhu, Chao-Yuan;Kuo, Shiao-Wei. And the article was included in Macromolecules (Washington, DC, United States) in 2016.Recommanded Product: 1075-62-3 This article mentions the following:

New supramol. polypeptides have been prepared through simple ring-opening polymerization and “click” reactions. Postfunctionalization with diaminopyridine (DAP) moieties, capable of multiple hydrogen bonding, was an efficient approach toward forming α-helical-dominant polypeptides. The phys. crosslinked networks produced upon self-organization of the DAP units increased the glass transition temperature (T_g) of the polymers and sustained the secondary structures of the polypeptides. Addnl. thermal responsivity resulted from dynamic noncovalent bonding on the polymer side chains. Mol. recognition through heterocomplementary DAP···thymine (T) base pairs was revealed spectroscopically and then used to construct poly(γ-propargyl-L-glutamate)-g-N-(6-acetamidopyridin-2-yl)-11-undecanamide/thyminylpyrene (PPLG-DAP/Py-T) supramol. complexes. Transmission electron microscopy images revealed that this complex was an efficient dispersant of carbon nanotubes (CNTs). Indeed, it could disperse CNTs in both polar and nonpolar media, the direct result of combining two modes of secondary noncovalent bonding: multiple hydrogen bonding and π-π interactions. Furthermore, CNT composites fabricated with biocompatible polymers and high value of T_g should enable the development of bio-inspired carbon nanostructures and lead the way toward their biomedical applications. In the experiment, the researchers used many compounds, for example, N-(6-Aminopyridin-2-yl)acetamide (cas: 1075-62-3Recommanded Product: 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). 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: 1075-62-3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Copper-catalyzed, N-auxiliary group-controlled switchable transannulation/nitration initiated by nitro radicals: selective synthesis of pyridoquinazolones and 3-nitroindoles was written by Shoberu, Adedamola;Li, Cheng-Kun;Qian, Hai-Feng;Zou, Jian-Ping. And the article was included in Organic Chemistry Frontiers in 2021.Reference of 175205-82-0 This article mentions the following:

Herein, a strategy based on the judicious choice of N-auxiliaries, which stabilize the substrates as well as allow precise and predictable control over their reactivity with tert-Bu nitrite was described. Thus, the stage was set for the copper-assisted, controllable synthesis of pyridoquinazolones or 3-nitroindoles. Mechanistic studies implicate a switch in the mechanism, in which N-2-pyridylindoles reacted via a nitrosation/transannulation process and N-2-pyridoylindoles underwent an amide bond dissociation/nitration sequence. Notably, the subsequent removal of the auxiliary groups was not required in these reactions. In the experiment, the researchers used many compounds, for example, 2-Bromo-3-(trifluoromethyl)pyridine (cas: 175205-82-0Reference of 175205-82-0).

2-Bromo-3-(trifluoromethyl)pyridine (cas: 175205-82-0) belongs to pyridine derivatives. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Reference of 175205-82-0

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

High-throughput screening for ionic liquids dissolving (ligno-)cellulose was written by Zavrel, Michael;Bross, Daniela;Funke, Matthias;Buechs, Jochen;Spiess, Antje C.. And the article was included in Bioresource Technology in 2009.Synthetic Route of C10H16ClN This article mentions the following:

The recalcitrance of lignocellulosic biomass poses a major challenge for its sustainable and cost-effective utilization. Therefore, an efficient pretreatment is decisive for processes based on lignocellulose. A green and energy-efficient pretreatment could be the dissolution of lignocellulose in ionic liquids Several ionic liquids were identified earlier which are capable to dissolve (ligno-)cellulose. However, due to their multitude and high costs, a high-throughput screening on small scale is essential for the determination of the most efficient ionic liquid In this contribution two high-throughput systems are presented based on extinction or scattered light measurements. Quasi-continuous dissolution profiles allow a direct comparison of up to 96 ionic liquids per experiment in terms of their dissolution kinetics. The screening results indicate that among the ionic liquids tested EMIM Ac is the most efficient for dissolving cellulose. Moreover, it was observed that AMIM Cl is the most effective ionic liquid for dissolving wood chips. In the experiment, the researchers used many compounds, for example, 1-Butyl-3-methylpyridinium Chloride (cas: 125652-55-3Synthetic Route of C10H16ClN).

1-Butyl-3-methylpyridinium Chloride (cas: 125652-55-3) 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. Synthetic Route of C10H16ClN

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Pd₂dba₃/P(t-Bu)₃H.BF₄/Cy₂NMe Catalyzed Heck Coupling in Synthesis of 3-Alkenyl-1H-Isochromen-1-Ones was written by Dasaradhan, Changalaraya;Nawaz Khan, Fazlur-Rahman. And the article was included in Polycyclic Aromatic Compounds in 2022.Application of 85838-94-4 This article mentions the following:

An efficient catalytic system comprising Pd₂dba₃/P(t-Bu)₃H.BF₄/Cy₂NMe -for the Heck coupling in the synthesis of 3-alkenyl isochromen-1-ones, I (R = H, 6,7-(OMe)₂; R¹ = Ph, benzyl, pyridin-2-yl), II (R² = OH, OMe, NH₂, butoxy) and III (R³ = 3,6-dihydro-2H-pyran-4-yl, 1-[(tert-butoxy)(oxo)methane]-1,2,5,6-tetrahydropyridin-3-yl) has been developed. Air stable alkyl phosphonium salt, [(t-Bu)₃Ph]BF₄ was found to be vital for the activation of 3- chloroisochromen-1-one and 3-chloro-6,7-dimethoxy-1H-isochromen-1-one, in regio-selective Heck coupling reactions. The technique has addnl. been reached out to typharin I, penicilisorin II and artemidin analogs III. In the experiment, the researchers used many compounds, for example, tert-Butyl 5,6-dihydropyridine-1(2H)-carboxylate (cas: 85838-94-4Application of 85838-94-4).

tert-Butyl 5,6-dihydropyridine-1(2H)-carboxylate (cas: 85838-94-4) 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. Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Application of 85838-94-4

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Pd-Catalyzed Directed Thiocyanation Reaction by C-H Bond Activation was written by Gao, Melissa;Chen, Mu-Yi;Pannecoucke, Xavier;Jubault, Philippe;Besset, Tatiana. And the article was included in Chemistry – A European Journal in 2020.Name: 2-(m-Tolyl)pyridine This article mentions the following:

The Pd-catalyzed directed thiocyanation reaction of arenes and heteroarenes by C-H bond activation was achieved. In the presence of an electrophilic SCN source, this original methodol. offered an efficient tool to access a panel of functionalized thiocyanated compounds I (R = H, 2-F, 4-OMe, etc.; DG = pyridin-2-yl, pyrimidin-2-yl, pyrazol-1-yl) (21 examples, up to 78% yield). Post-functionalization reactions further demonstrated the synthetic utility of the approach by converting the SCN-containing mols. into value-added scaffolds. In the experiment, the researchers used many compounds, for example, 2-(m-Tolyl)pyridine (cas: 4373-61-9Name: 2-(m-Tolyl)pyridine).

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. Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Name: 2-(m-Tolyl)pyridine

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

2,2′-Homocoupled Azine N,N’-Dioxides or Azine N-Oxides: CDC- or S_NAr-Controlled Chemoselectivity was written by Jha, Abadh Kishor;Jain, Nidhi. And the article was included in European Journal of Organic Chemistry in 2017.Name: 2-(m-Tolyl)pyridine This article mentions the following:

An unprecedented Cu(OAc)₂– and LiOtBu-mediated homocoupling of azine N-oxides to yield 2,2′-azine N,N’-dioxides is reported. This is the first instance in which copper was used to catalyze the homodimerization reaction, especially of 2-phenylpyridine N-oxides. In the absence of catalytic copper, the reaction follows an alternative pathway, and instead of dioxides it yields 2,2′-azine N-monoxides. This latter protocol works efficiently with a range of N-heterocyclic oxides of pyridine, 2-phenylpyridine, quinoline and N-aryl-1,2,3-triazole. It is scalable, offers high regioselectivity and gives the products in moderate to high yields. The observed chemoselectivity between the copper-assisted and copper-free protocols is routed through oxidative cross-dehydrogenative coupling (CDC) and nucleophilic aromatic substitution of hydrogen (S_NAr) pathways, resp. In the experiment, the researchers used many compounds, for example, 2-(m-Tolyl)pyridine (cas: 4373-61-9Name: 2-(m-Tolyl)pyridine).

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

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Prediction of blood-brain barrier permeation using quantum chemically derived information was written by Hutter, Michael C.. And the article was included in Journal of Computer-Aided Molecular Design in 2003.Formula: C8H11N This article mentions the following:

A model for the prediction of the blood-brain distribution (logBB) is obtained by multiple regression anal. of mol. descriptors for a training set of 90 compounds The majority of the descriptors are derived from quantum chem. information using semi-empirical AM1 calculations to compute fundamental properties of the mols. investigated. The polar surface area of the compounds can be described appropriately by six descriptors derived from the mol. electrostatic potential. This set shows a strong correlation with the observed logBB. Addnl. quantum chem. computed properties that contribute to the final model comprise the ionization potential and the covalent hydrogen-bond basicity. Complementary descriptors account for the presence of certain chem. groups, the number of hydrogen-bond donors, and the number of rotatable bonds of the compounds The quality of the fit is further improved by including variables derived from principal component anal. of the mol. geometry. 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. 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 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

Preparation of isopropyl- and tert-butylpyridines from methylpyridines by phase-transfer catalyzed alkylation was written by Hart, Lionel S.;Killen, Christopher R. J.;Saunders, Kenwyn D.. And the article was included in Journal of the Chemical Society, Chemical Communications in 1979.Application In Synthesis of 2-Isopropylpyridine This article mentions the following:

2-Methylpyridine on quaternization with MeI, followed by alkylation with MeI in aqueous NaOH/CH₂Cl₂ catalyzed by Bu₄N⁺ OH^– and dequaternization with 4-MeC₆H₄SNa (I), gave 36% 2-isopropylpyridine. Similar sequential quaternization, phase-transfer-catalyzed methylation and dequaternization of 2,6-dimethylpyridine gave 40% 2,6-diisopropylpyridine, whereas 4-methylpyridine gave 37% 4-tert-butylpyridine. 4-tert-Butyl-2,6-diisopropylpyridine was similarly obtained (20%) from 2,4,6-trimethylpyridine. Contact with a CH₂Cl₂ solution of the dequaternization products may lead to an allergic reaction resulting in extreme sensitivity to contact with I. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Application In Synthesis 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.Application In Synthesis of 2-Isopropylpyridine

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Reactivity model for the Menschutkin reaction. Methylation of alkyl-substituted and heterosubstituted pyridines was written by Schug, John C.;Viers, Jimmy W.;Seeman, Jeffrey I.. And the article was included in Journal of Organic Chemistry in 1983.Reference of 644-98-4 This article mentions the following:

The relative activation energies for the methylation of pyridine and 37 alkyl- and 6 heterosubstituted pyridines were calculated using semiempirical all-valence electron (MINDO/3) SCF procedures. The alkylation rates covered >5 orders of magnitude. A reactivity model was constructed by placing a Me⁺ moiety 1.88 Å from the pyridine N and completely optimizing the Me⁺-substrate supermol. A transition-state (TS) model was determined by considering the dequaternization of the N-methylpyridinium cation. The energy difference between the TS model and the completely optimized ground-state mol. for the 44 compounds resulted in a good correlation with the logarithms of the methylation rate constants Implications of this work to nonadditive steric and electronic effects are considered. The model is used to evaluate changes in the TS position in these methylations. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Reference of 644-98-4).

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. 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.Reference of 644-98-4

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Rhodium-Catalyzed Pyridine N-Oxide Assisted Suzuki-Miyaura Coupling Reaction via C(O)-C Bond Activation was written by Zhong, Jing;Long, Yang;Yan, Xufei;He, Shiyu;Ye, Runyou;Xiang, Haifeng;Zhou, Xiangge. And the article was included in Organic Letters in 2019.Synthetic Route of C7H6N2 This article mentions the following:

A rhodium-catalyzed Suzuki-Miyaura coupling reaction via C(O)-C bond activation to form 2-benzoylpyridine N-oxide derivatives is reported. Both the C(O)-C(sp²) and C(O)-C(sp³) bond could be activated during the reaction with yields up to 92%. The N-oxide moiety could be employed as a traceless directing group, leading to free pyridine ketones. In the experiment, the researchers used many compounds, for example, 4-Methylpicolinonitrile (cas: 1620-76-4Synthetic Route of C7H6N2).

4-Methylpicolinonitrile (cas: 1620-76-4) 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.Synthetic Route of C7H6N2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem