Tag: 100-200

Effects of the Cationic Structure on the Adsorption Performance of Ionic Polymers toward Au(III): an Experimental and DFT Study was written by Kou, Xin;Ma, Yutian;Pan, Congming;Huang, Yong;Duan, Yulai;Yang, Ying. And the article was included in Langmuir in 2022.Related Products of 628-13-7 This article mentions the following:

Ionic polymers have been proven to be promising adsorbents in recovering Au(III) due to their advantages of simple synthesis and high adsorption efficiency. However, the unclarity of the relationship between the adsorption ability of ionic polymers and their cationic structures hinders further optimization of their adsorption performance. This study synthesized a series of ionic polymers with pyridinium, imidazolium, piperidinium, pyrrolidinium, and triethylammonium cations to discover the effects of the cationic structure on their adsorption properties. Exptl. results show that the existence of anion-π interaction between aromatic cations and [AuCl₄]^– makes the aromatic cations-anion interaction stronger, which does not enhance the adsorption performance of the aromatic-based ionic polymer. This is due to the charge delocalization in the aromatic ring, resulting in a lower electrostatic potential (ESP) of aromatic cations than that of aliphatic cations with a localized charge. The higher the ESP of cations, the better the adsorption performance of the corresponding ionic polymer. This study serves as a deep understanding of the cationic structure-adsorptive performance relationship of the ionic polymer at the mol. level and further provides a theor. guidance to optimize the adsorption performance of ionic polymers. In the experiment, the researchers used many compounds, for example, Pyridinehydrochloride (cas: 628-13-7Related Products of 628-13-7).

Pyridinehydrochloride (cas: 628-13-7) 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.Related Products of 628-13-7

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Structure-toxicity analyses of Tetrahymena pyriformis exposed to pyridines – an examination into extension of surface-response domains was written by Seward, J. R.;Cronin, M. T. D.;Schultz, T. W.. And the article was included in SAR and QSAR in Environmental Research in 2001.COA of Formula: C6H6N2O3 This article mentions the following:

A selection of mechanistically diverse substituted pyridines were tested in the Tetrahymena pyriformis population growth impairment assay. The response-surface approach was used to derive multiple-regression type structure-toxicity relationships between T. pyriformis population growth impairment toxicity data (log (IGC₅₀^-1)) and the 1-octanol/water partition coefficient (log K_ow) and one of two different descriptors of MO interaction: energy of the LUMO (E_LUMO) and maximum acceptor superdelocalizability (S_MAX). A statistically robust model (log (IGC₅₀^-1) = -3.91+0.50 (log K_ow) + 10.70(S_MAX); n = 83, r² = 0.756, s = 0.38, F = 124, Pr > F = 0.0001) was developed with S_MAX as the indicator of reactivity. This model was not statistically different in fit from the model (log (IGC₅₀^-1) = -1.19+0.56 (log K_ow) – 0.61 (E_LUMO); n = 86, r² = 0.749, s = 0.38, F = 124, Pr > F = 0.0001) derived using the alternative descriptor of electrophilic interaction. Compounds with high residual values were removed. An examination of these outliers from both response-surfaces, revealed that pyridines substituted in the 2-position with electron-releasing groups and halogenated nitro-substituted pyridines did not fit the above models well. A third group of outliers, the mono-halogenated pyridines, was unique to the S_MAX response-surface, which are neutral narcotics with potentially high volatility. A comparison of observed and predicted toxicities for a validation set of pyridines for the S_MAX surface (log (observed IGC₅₀^-1) = 0.10+0.75 (log (predicted IGC₅₀^-1)); n = 10, r² = 0.662, s = 0.49, F = 15.7, Pr > F = 0.004) and the E_LUMO surface (log (observed IGC₅₀^-1) = 0.17+0.80 (log (predicted IGC₅₀^-1)); n = 10, r² = 0.707, s = 0.45, F = 19.3, Pr > F = 0.002) validated the above models, with the fit in the same range as the parent model. The model derived with S_MAX was compared to the response-surface derived for substituted benzenes (log (IGC₅₀^-1) = -3.47+0.50 (log K_ow) + 9.85(S_MAX); n = 197, r² = 0.816, s = 0.34, F = 429, Pr > F = 0.0001) revealing the similarities in slope and intercept between the two response-surfaces. The model fit was poorer for the pyridine surface, which may be a factor of increased reactivity due to the presence of nitrogen and the associated pair of unshared electrons in the ring not present in benzene. However, the similarity of the pyridine and benzene response-surfaces suggests that the domain defined for benzenes may be extended to encompass nitrogen heterocyclic pyridines. In the experiment, the researchers used many compounds, for example, 3-Hydroxy-6-methyl-2-nitropyridine (cas: 15128-90-2COA of Formula: C6H6N2O3).

3-Hydroxy-6-methyl-2-nitropyridine (cas: 15128-90-2) 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. 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.COA of Formula: C6H6N2O3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Synthesis of some substituted methyl pyridinecarboxylates. II. Methyl 4-substituted picolinates, methyl 5-substituted picolinates, and methyl 5-substituted nicotinates was written by Deady, L. W.;Shanks, R. A.;Campbell, Arthur Derek;Chooi, S. Y.. And the article was included in Australian Journal of Chemistry in 1971.Application of 24103-75-1 This article mentions the following:

The preparation of substituted Me pyridinecarboxylates is described. Me 4-X-substituted picolinates and methyl 5-X-substituted picolinates (X = NO2, Br, MeO, Me2N) are prepared from 2-picoline via 4-nitro-2-picoline N-oxide and 2-amino-5-nitropyridine, resp. Me 5-X-substituted nicotinates (X = Br, MeO, Me2N) are prepared from 5-bromonicotinic acid. Preparations of Me 4-methylpicolinate and Me 5-methylnicotinate from the corresponding lutidines and Me 5-methylpicolinate from 2-amino-5-methylpyridine are described. In the experiment, the researchers used many compounds, for example, 4-Methoxy-2-methylpyridine (cas: 24103-75-1Application of 24103-75-1).

4-Methoxy-2-methylpyridine (cas: 24103-75-1) 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.Application of 24103-75-1

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

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

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

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

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

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

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