Day: February 13, 2023

Simultaneous Estimation of Two Coupled Hydrogen Bond Geometries from Pairs of Entangled NMR Parameters: The Test Case of 4-Hydroxypyridine Anion was written by Tupikina, Elena Yu.;Sigalov, Mark V.;Tolstoy, Peter M.. And the article was included in Molecules in 2022.Application of 626-64-2 This article mentions the following:

The computational method for estimating the geometry of two coupled hydrogen bonds with geometries close to linear using a pair of spectral NMR parameters was proposed. The method was developed based on the quantum-chem. investigation of 61 complexes with two hydrogen bonds formed by oxygen and nitrogen atoms of the 4-hydroxypyridine anion with OH groups of substituted methanols. The main idea of the method is as follows: from the NMR chem. shifts of nuclei of atoms forming the 4-hydroxylpyridine anion, we select such pairs, whose values can be used for simultaneous determination of the geometry of two hydrogen bonds, despite the fact that every NMR parameter is sensitive to the geometry of each of the hydrogen bonds. For these parameters, two-dimensional maps of dependencies of NMR chem. shifts on interat. distances in two hydrogen bonds were constructed. It is shown that, in addition to chem. shifts of the nitrogen atom and quaternary carbon, which are exptl. difficult to obtain, chem. shifts of the carbons and protons of the CH groups can be used. The performance of the proposed method was evaluated computationally as well on three addnl. complexes with substituted alcs. It was found that, for all considered cases, hydrogen bond geometries estimated using two-dimensional correlations differed from those directly calculated by quantum-chem. methods by not more than 0.04 鑴? In the experiment, the researchers used many compounds, for example, Pyridin-4-ol (cas: 626-64-2Application 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璺痬ol閳? in pyridine vs. 150 kJ璺痬ol閳? in benzene). Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Application of 626-64-2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Enantio- and Regioselective Ni-Catalyzed para-C-H Alkylation of Pyridines with Styrenes via Intermolecular Hydroarylation was written by Ma, Jun-Bao;Zhao, Xia;Zhang, Dongju;Shi, Shi-Liang. And the article was included in Journal of the American Chemical Society in 2022.Formula: C8H11N This article mentions the following:

Herein the first enantioselective para-C-H activation of pyridines through the use of a Ni-Al bimetallic catalyst system and N-heterocyclic carbene (NHC) ligand for intermol. hydroarylation of styrenes was described. The reaction proceeded in high to excellent enantioselectivities (up to 98.5:1.5 er) and high site-selectivities for both styrene and pyridine components (up to >98:2). Consequently, a broad range of enantioenriched 1,1-diarylalkanes containing pyridine moieties could be prepared in a single step with 100% atom economy. Computational studies supported a mechanism involving a ligand-to-ligand H-transfer (LLHT) and reductive elimination sequence, with LLHT being the rate- and enantioselectivity-determining step. DFT studies indicated that the 锜?锜?stacking interaction between the NHC aryl fragment and trans-styrenes was critical for high reactivity and enantiocontrol. 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. 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.Formula: C8H11N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Efficacy of difenoconazole emulsifiable concentrate with ionic liquids against cucumbers powdery mildew was written by Peng, Qingrong;Liu, Fengmao;Zhang, Chunrong. And the article was included in International Journal of Chemical Engineering in 2017.Category: pyridine-derivatives This article mentions the following:

Among eight ionic liquids (ILs) examined, 1-n-butyl-4-methyl-pyridinium bromide (BMPyBr, 5) was used in this study as an appropriate alternative to benzene homologs and derivatives to be used in 10 wt% water-insoluble difenoconazole emulsifiable concentrate (EC). Moreover, 10 wt% difenoconazole EC with BMPyBr (5) exhibited the same efficacy as 10 wt% difenoconazole wettable powder (WP) against powdery mildew on cucumbers under field conditions.The results revealed that difenoconazole EC with BMPyBr (5) had excellent stability at 268K and 327K after 14 days through high-performance liquid chromatog. (HPLC). Therefore, ILs can be considered as promising environment-friendly adjuvants for pesticides that are com. processed as EC formulation. In the experiment, the researchers used many compounds, for example, 1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6Category: pyridine-derivatives).

1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6) belongs to pyridine derivatives. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. 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.Category: pyridine-derivatives

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Preparation of new nitrogen-bridged heterocycles. 42. Synthesis and the reaction of pyridinium N-ylides using bifunctional ethyl thiocyanatoacetates was written by Kakehi, Akikazu;Ito, Suketaka;Hashimoto, Yasunobu. And the article was included in Bulletin of the Chemical Society of Japan in 1996.Formula: C7H7ClN2 This article mentions the following:

Various pyridinium (monosubstituted methylide)s I (R², R³, R⁴ = H, Me; R⁵ = cyano, CO₂Et, COMe, COPh) were smoothly attached to the cyano group in Et thiocyanatoacetate or Et 2-thiocyanatopropionate to afford the corresponding pyridinium (substituted cyanomethylide)s II in low-to-moderate yields, while pyridinium (unsubstituted amidate)s III (R¹, R², R³ = H, Me) reacted with the ester carbonyl group in the same reagents to give pyridinium (thiocyanatoacetato)- or (2-thiocyanatopropiono)amidates IV in considerable yields. The 1,3-dipolar cycloadditions of some pyridinium (unsym. substituted cyanomethylide)s with di-Me acetylenedicarboxylate (DMAD) in various solvents afforded only di-Me 3-cyanoindolizine-1,2-dicarboxylate, except for a few examples. On the other hand, the treatment of pyridinium (thiocyanatoaceto)- or (2-thiocyanatopropiono)amidates with a strong base, such as potassium tert-butoxide, gave new bicyclic mesoionic compounds, N-[2-(1,3,4-thiadiazolo[3,2-a]pyridinio)]acetamidate derivatives V, in moderate yields. The intermediacy of N-[1-(2-thiocyanatopyridinio)]acetamidates in the formation reactions of the latter compounds was also proven by independent syntheses. In the experiment, the researchers used many compounds, for example, 1-(Cyanomethyl)pyridin-1-ium chloride (cas: 17281-59-3Formula: C7H7ClN2).

1-(Cyanomethyl)pyridin-1-ium chloride (cas: 17281-59-3) 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. 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. Formula: C7H7ClN2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Discovery and optimization of adamantyl carbamate inhibitors of 11灏?HSD1 was written by Tice, Colin M.;Zhao, Wei;Krosky, Paula M.;Kruk, Barbara A.;Berbaum, Jennifer;Johnson, Judith A.;Bukhtiyarov, Yuri;Panemangalore, Reshma;Scott, Boyd B.;Zhao, Yi;Bruno, Joseph G.;Howard, Lamont;Togias, Jennifer;Ye, Yuan-Jie;Singh, Suresh B.;McKeever, Brian M.;Lindblom, Peter R.;Guo, Joan;Guo, Rong;Nar, Herbert;Schuler-Metz, Annette;Gregg, Richard E.;Leftheris, Katerina;Harrison, Richard K.;McGeehan, Gerard M.;Zhuang, Linghang;Claremon, David A.. And the article was included in Bioorganic & Medicinal Chemistry Letters in 2010.Category: pyridine-derivatives This article mentions the following:

Synthesis of 2-adamantyl carbamate derivatives of piperidines and pyrrolidines led to the discovery of 2-adamantanyl (3R)-3-tert.-butoxycarbonylaminopyrrolidine-1-carboxylate with an IC₅₀ of 15.2 nM against human 11灏?HSD1 in adipocytes. Optimization for increased adipocyte potency, metabolic stability and selectivity afforded 1-carbamoyladmanatan-4-yl (3R)-(3-cyano- and 5-cyanopyrdinylamino)pyrrolidine-1-carboxylate, both of which were >25% orally bioavailable in rat. In the experiment, the researchers used many compounds, for example, 2-Bromo-3-(trifluoromethyl)pyridine (cas: 175205-82-0Category: pyridine-derivatives).

2-Bromo-3-(trifluoromethyl)pyridine (cas: 175205-82-0) belongs to pyridine derivatives. Pyridine has a conjugated system of six 锜?electrons that are delocalized over the ring. The molecule is planar and, thus, follows the H鐪塩kel criteria for aromatic systems. Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Category: pyridine-derivatives

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Utilizing Selective Chlorination to Synthesize New Triangulenium Dyes was written by Jensen, Jesper Dahl;Bisballe, Niels;Kacenauskaite, Laura;Thomsen, Maria Storm;Chen, Junsheng;Hammerich, Ole;Laursen, Bo W.. And the article was included in Journal of Organic Chemistry in 2021.Quality Control of Pyridinehydrochloride This article mentions the following:

Functionalization of new sites on the triangulenium structure has been achieved by early stage chlorination with N-chlorosuccinimide (NCS), giving rise to two new triangulenium dyes (1 and 3). By introducing the chlorine functionalities in the acridinium precursor, positions complementary to those previously accessed by electrophilic aromatic substitution on the final dyes are accessed. The chlorination is selective, giving only one regioisomer for both mono- and dichlorination products. For the monochlorinated acridinium compound a highly selective ring-closing reaction was discovered, generating a single regioisomer of the cationic [4]helicene product. Further investigations into the mechanism of [4]helicene formation lead to the first isolation of the previously proposed intermediate of the two-step S_NAr reaction, key to all aza-bridged triangulenium and helicenium systems. Late-stage functionalization of DAOTA⁺ with NCS gave rise to a different dichlorinated compound (2). The fully ring closed chlorinated triangulenium dyes 1, 2 and 3 show red shift in absorption and emission, while maintaining relatively high fluorescence quantum yields of 36%, 26%, and 41%, and long fluorescence lifetimes of 15 ns, 12.5 and 16 ns, resp. Cyclic voltammetry shows that chlorination of the triangulenium dyes significantly lowers reduction potentials and thus allows for efficient tuning of redox and photoredox properties. In the experiment, the researchers used many compounds, for example, Pyridinehydrochloride (cas: 628-13-7Quality Control of Pyridinehydrochloride).

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.Quality Control of Pyridinehydrochloride

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Rhodium-Catalyzed Regioselective Synthesis of Isoindolium Salts from 2-Arylpyridines and Alkenes in Aqueous Medium under Oxygen was written by Upadhyay, Nitinkumar Satyadev;Jayakumar, Jayachandran;Cheng, Chien-Hong. And the article was included in Advanced Synthesis & Catalysis in 2016.Recommanded Product: 2-(m-Tolyl)pyridine This article mentions the following:

A highly regioselective synthesis of pyrido[2,1-a]isoindolium salts, e.g., I (X-rays single crystal structure shown), from 2-arylpyridines and two equivalent of electron-deficient alkenes catalyzed by rhodium is demonstrated. The reaction was carried out in aqueous medium at 110 鎺矯 using inexpensive oxygen as oxidant. Reverse aza-Michael addition of the isoindolium salt occurs when the salt was treated with base to give a 灏?disubstituted alkene product. A reaction mechanism involving an ortho C-H olefination of 2-arylpyridine by alkene, intramol. aza-Michael addition, deprotonation at the 灏?carbon of the alkene fragment followed by another Michael addition to give the final product is proposed. In the experiment, the researchers used many compounds, for example, 2-(m-Tolyl)pyridine (cas: 4373-61-9Recommanded Product: 2-(m-Tolyl)pyridine).

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. Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C閳ユ弻 in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Recommanded Product: 2-(m-Tolyl)pyridine

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Qualitative and quantitative structure activity relationships for the inhibitory effects of cationic head groups, functionalized side chains and anions of ionic liquids on acetylcholinesterase was written by Arning, Juergen;Stolte, Stefan;Boeschen, Andrea;Stock, Frauke;Pitner, William-Robert;Welz-Biermann, Urs;Jastorff, Bernd;Ranke, Johannes. And the article was included in Green Chemistry in 2008.Application In Synthesis of 1-Butyl-3-methylpyridinium Chloride This article mentions the following:

To contribute to a deeper insight into the hazard potential of ionic liquids to humans and the environment, an acetylcholinesterase (AchE) inhibition screening assay was used to identify toxicophore substructures and interaction potentials mediating enzyme inhibition. The pos. charged nitrogen atom, a widely delocalized aromatic system, and the lipophilicity of the side chains connected to the cationic head groups can be identified as the key structural elements in binding to the enzymes active site. With respect to this, the dimethylaminopyridinium, the quinolinium and the pyridinium head groups exhibit a very strong inhibitory potential to the enzyme with IC₅₀ values around 10 娓璏. In contrast, the polar and non-aromatic morpholinium head group is found to be only weakly inhibiting to the enzyme activity, with IC₅₀ values > 500 娓璏. The introduction of polar hydroxy, ether or nitrile functions into the alkyl side chain is shown to be a potent structural alteration to shift the corresponding ionic liquids to a lower inhibitory potential. Supporting this fact, for a series of imidazolium cations, a QSAR correlation was set up by the linear regression of the log IC₅₀ vs. the logarithm of the HPLC-derived lipophilicity parameter k₀. Addnl., a broad set of anion species (inorganic, organic and complex borate anions), commonly used as ionic liquid counterions, was tested and the vast majority exhibited no effect on AchE. Only the fluoride and fluoride containing anion species which readily undergo hydrolytic cleavage can be identified to act as AchE inhibitors. In the experiment, the researchers used many compounds, for example, 1-Butyl-3-methylpyridinium Chloride (cas: 125652-55-3Application In Synthesis of 1-Butyl-3-methylpyridinium Chloride).

1-Butyl-3-methylpyridinium Chloride (cas: 125652-55-3) 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). 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. Application In Synthesis of 1-Butyl-3-methylpyridinium Chloride

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Synthesis of 2-pyridinamines and their alkyl derivatives from 2-cyanopyridines was written by Dai, Liyan;Fang, Jun;Wang, Xiaozhong;Chen, Yingqi. And the article was included in Huagong Xuebao (Chinese Edition) in 2007.Recommanded Product: 3,6-Dimethyl-2-pyridinamine This article mentions the following:

The preparation of a series of 2-pyridinamines and their alkyl derivatives is described. The target compounds are synthesized starting from corresponding 2-cyanopyridines, via incomplete hydrolysis in the presence of hydrogen peroxide in the dilute alk. mixture of acetone-2% sodium hydroxide solution, and Hoffmann degradation reaction with freshly made NaBrO. This route is of industrial value because of cheap and readily available materials, moderate reaction conditions and convenient operations. In the experiment, the researchers used many compounds, for example, 3,6-Dimethyl-2-pyridinamine (cas: 823-61-0Recommanded Product: 3,6-Dimethyl-2-pyridinamine).

3,6-Dimethyl-2-pyridinamine (cas: 823-61-0) 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.Recommanded Product: 3,6-Dimethyl-2-pyridinamine

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem