Day: January 5, 2023

New Strategic Reactions for Organic Synthesis: Catalytic Asymmetric C-H Activation α to Nitrogen as a Surrogate for the Mannich Reaction was written by Davies, Huw M. L.;Venkataramani, Chandrasekar;Hansen, Tore;Hopper, Darrin W.. And the article was included in Journal of the American Chemical Society in 2003.Electric Literature of C10H17NO2 This article mentions the following:

The asym. C-H activation reactions of Me aryldiazoacetates are readily induced by the rhodium prolinate catalyst Rh₂(S-DOSP)₄ [DOSP = (4-dodecylphenylsulfonyl)prolinato] or the bridged prolinate catalysts, and the donor/acceptor-substituted carbenoids generated displayed remarkable chemoselectivity, which allows for highly regioselective, diastereoselective, and enantioselective reactions to be achieved. For example, the C-H activation/rhodium carbenoid induced insertion reactions of N-Boc-protected cyclic amines I (n = 1, 3, 4) with Me phenyldiazoacetate gave the corresponding esters II with excellent diastereoselectivity and enantioselectivity. Furthermore, the reactions can display high levels of double stereodifferentiation and kinetic resolution, as shown in the studies of the double C-H activation/carbenoid insertion reactions. In the experiment, the researchers used many compounds, for example, tert-Butyl 5,6-dihydropyridine-1(2H)-carboxylate (cas: 85838-94-4Electric Literature of C10H17NO2).

tert-Butyl 5,6-dihydropyridine-1(2H)-carboxylate (cas: 85838-94-4) 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, 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 C10H17NO2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Cost Efficient Synthesis of Diaryl Ethers Catalyzed by CuI, Imidazolium Chloride and Cs₂CO₃ was written by Paul, Sudeep;Joy, Bony P.;Rajendran, Rajarajan;Gudimetla, Vittal B.. And the article was included in ChemistrySelect in 2019.HPLC of Formula: 4783-68-0 This article mentions the following:

Synthetically versatile imidazolium chlorides, especially 1,3-bis-(2,6-diisopropylphenyl)-imidazolium chloride (IPrHCl) along with copper (I) iodide and cesium carbonate, were found to be useful to form C-O bonds via O-arylation of phenols with aryl halides to afford diaryl ethers ArOAr¹ [Ar = Ph, 4-MeC₆H₄, 4-ClC₆H₄, etc.; Ar¹ = Ph, 4-MeOC₆H₄, 2-pyridyl, etc.]. In this catalysis, the metal:ligand (Cu:IPr) loading was optimized to 1.0 mol%, making it an inexpensive and a simple one pot catalytic route for synthesizing a variety of diaryl ethers. The catalytic cycle was probed by UV-Vis, FT-IR and HRMS techniques confirming involvement of a copper-imidazolium-carbonate complex. In the experiment, the researchers used many compounds, for example, 2-Phenoxypyridine (cas: 4783-68-0HPLC of Formula: 4783-68-0).

2-Phenoxypyridine (cas: 4783-68-0) 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 derivatives are also useful as small-molecule α-helix mimetics that inhibit protein-protein interactions, as well as functionally selective GABA ligands.HPLC of Formula: 4783-68-0

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Effect of substituents on the nickel-induced contact shifts in aromatic amines. Comparison with spin delocalization in phenyl, benzyl, and related radicals was written by Underwood, Graham R.;Clyde, William C.;Zitter, Mark S.. And the article was included in Journal of Physical Chemistry in 1981.Reference of 644-98-4 This article mentions the following:

Ni[CH(COMe)₂]₂ (I)-induced proton and ¹³C NMR contact shifts were studied in a series of anilines, pyridines and heterocycles. Substituents have little effect on the shifts unless bonded directly to N or separated from it by just 1 atom. INDO calculations on 2-substituted Ph radicals suggest that the singly occupied orbital is bent slightly away from the substituent; the ESR hyperfine splitting constants as well as the Ni-induced shifts reflect this distortion. The specificity of I for the N lone pair, the relative constancy of its induced shifts, and their ready interpretation make this a useful NMR shift reagent for amines. 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’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. 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.Reference of 644-98-4

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Rapid determination of chemical composition in the particulate matter of cigarette mainstream smoke was written by Wang, Xinxin;Jiang, Qing;Li, Hongli;Chen, David D. Y.. And the article was included in Talanta in 2020.Quality Control of Pyridin-4-ol This article mentions the following:

Particulate matter from mainstream smoke (MSS) is significantly hazardous when inhaled into the human body. An ambient ionization mass spectrometric method, direct anal. in real time mass spectrometry (DART-MS), was applied to rapidly and simultaneously measure multiple particulate components in MSS. A variety of compounds were obtained in seconds, where different types of cigarettes and different solvent extracts generated distinct chem. constituents as validated by principle component anal. Chem. formula assignment and compound identification were based on accurate m/z values with mass errors <10 ppm. Quantitation of nicotine was achieved using an isotope internal standard with DART-MS. Method validation with chromatog.-MS anal. further proved the advantages of DART-MS with respect to anal. speed and operational simplicity for the direct evaluation of complex samples. DART-MS is feasible for the rapid acquisition of cigarette fingerprints for quality control as well as for quant. assessment of carcinogens for harm reduction In the experiment, the researchers used many compounds, for example, Pyridin-4-ol (cas: 626-64-2Quality Control of Pyridin-4-ol).

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). 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.Quality Control of Pyridin-4-ol

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Antiparasitic agents. 3. Synthesis and anthelmintic activities of novel 2-pyridinyl-5-isothiocyanatobenzimidazoles was written by Haugwitz, R. D.;Maurer, B. V.;Jacobs, G. A.;Narayanan, V. L.;Cruthers, L.;Szanto, J.. And the article was included in Journal of Medicinal Chemistry in 1979.Recommanded Product: 1620-76-4 This article mentions the following:

The title compounds I (R¹ = H, Cl, O, Me, MeO, NCS; R² = H, Cl, or Me; R³ = H or NCS) were prepared and tested for anthelmintic activity in mice exptl. infected with Nematospiroides dubius (nematode) and Hymenolepis nana (Tapeworm), and in sheep naturally infected with gastrointestinal nematodes. The compounds were used at 0.2% in the mouse diet and at 50 mg/kg, orally in sheep. None of the compounds showed activity against N. dubius, 6 showed 100% activity against H. nana and 1-isothiocyanato-2-(2-pyridinyl)-1H-benzimidazole [71134-39-9] showed nematocidal activity in sheep. Maximum activity required attachment of SCN group at the 5(6) position. Structural activity relations are discussed. In the experiment, the researchers used many compounds, for example, 4-Methylpicolinonitrile (cas: 1620-76-4Recommanded Product: 1620-76-4).

4-Methylpicolinonitrile (cas: 1620-76-4) 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. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Recommanded Product: 1620-76-4

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Dual resonance functionality in pyridine 1-oxides. A double multinuclear NMR approach was written by Sawada, Masami;Takai, Yoshio;Yamano, Satoshi;Misumi, Soichi;Hanafusa, Terukiyo;Tsuno, Yuho. And the article was included in Journal of Organic Chemistry in 1988.Application In Synthesis of 3,5-Dimethylpyridine 1-oxide This article mentions the following:

Substituent effects on the nitrogen-15 NMR chem. shifts of 3- and 4-substituted pyridine 1-oxides in DMSO at natural abundance are reported for 26 derivatives A bilinear relationship is found between the ¹⁵N SCS (substituent chem. shift) of pyridine 1-oxides and the ¹³C SCS of the corresponding mono-substituted benzenes. Both the present ¹⁵N SCS data and the reported ¹⁷O SCS data of pyridine 1-oxides are analyzed by using the Ukawa-Tsuno’s LSFE and the Taft’s DSP LFER. The historically-accepted dual functionality of pyridine 1-oxides can be successfully expressed in terms of electron-donating and electron-accepting pi-electronic contributions by means of the LSFE treatment. The resulting internal consistency of the constant pi-electronic effect’s ratio, ρ_π⁺/ρ_π^– = 1.4, on the detecting nitrogen and oxygen is taken as evidence for justification of the dual functionality of the pyridinee 1-oxides and then, for rationalization of the LSFE treatment. 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. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. 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 3,5-Dimethylpyridine 1-oxide

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Biosilica as an efficient heterogeneous catalyst for ipso-hydroxylation of arylboronic acids was written by Mahanta, Abhijit;Adhikari, Pooja;Bora, Utpal;Thakur, Ashim Jyoti. And the article was included in Tetrahedron Letters in 2015.HPLC of Formula: 51834-97-0 This article mentions the following:

A mild and efficient protocol for the conversion of arylboronic acids to phenol via ipso-hydroxylation was developed using aqueous hydrogen peroxide as oxidant and biosilica as heterogeneous catalyst. The recyclability of the catalyst is also evaluated and could be reused up to six consecutive cycles without a significant loss in catalytic activity. In the experiment, the researchers used many compounds, for example, 5-Hydroxy-2-methoxylpyridine (cas: 51834-97-0HPLC of Formula: 51834-97-0).

5-Hydroxy-2-methoxylpyridine (cas: 51834-97-0) 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. 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.HPLC of Formula: 51834-97-0

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Adsorption of Brij 35-dodecylpyridinium bromide mixtures at air-aqueous solution and Teflon-aqueous solution interfaces was written by Pisaev, I. V.;Soboleva, O. A.;Ivanova, N. I.. And the article was included in Colloid Journal in 2009.Electric Literature of C17H30BrN This article mentions the following:

Tensiometry, spectrophotometry, the radioactive-tracer technique, and contact angle measurements are employed to study the adsorption of mixtures of a nonionic surfactant Brij 35 and a cationic surfactant dodecylpyridinium bromide (DDPB) at interfaces between their solutions and air or Teflon. It is established that adsorption layers at both of the interfaces are enriched with Brij 35. Brij 35 adsorption on Teflon is nearly independent of the presence of DDPB. On the contrary, DDPB adsorption is enhanced in the presence of Brij 35. Neg. deviations from the ideal behavior are revealed for mixtures with small fractions of Brij 35 with respect to a decrease in the interfacial tension in air-solution and Teflon-solution systems. In the experiment, the researchers used many compounds, for example, 1-Dodecylpyridin-1-ium bromide (cas: 104-73-4Electric Literature of C17H30BrN).

1-Dodecylpyridin-1-ium bromide (cas: 104-73-4) 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 derivatives are also useful as small-molecule α-helix mimetics that inhibit protein-protein interactions, as well as functionally selective GABA ligands.Electric Literature of C17H30BrN

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Reactions of Organomagnesates and Aryl Halides: Metalation and Nucleophilic Substitution was written by Farkas, Julius Jr.;Stoudt, Scott J.;Hanawalt, Erin M.;Pajerski, Anthony D.;Richey, Herman G. Jr.. And the article was included in Organometallics in 2004.Formula: C11H17N This article mentions the following:

Reactions with aryl halides (ArX) of preparations obtained in di-Et ether from an R₂Mg compound and a cryptand, an alkali-metal alkoxide, or tetrabutylammonium bromide lead to ArH and ArR. ArH results from magnesium-halogen exchange, and ArR results from aryne formation. Reactions of similar preparations with pyridine lead to formation of larger amounts of substitution product, and those with 2-cyclohexen-1-one to larger amounts of 1,4-addition product, than do reactions of R₂Mg alone. In the experiment, the researchers used many compounds, for example, 4-Hexylpyridine (cas: 27876-24-0Formula: C11H17N).

4-Hexylpyridine (cas: 27876-24-0) 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. 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: C11H17N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Gram-Scale Synthesis of β-(Hetero)arylethenesulfonyl Fluorides via a Pd(OAc)₂ Catalyzed Oxidative Heck Process with DDQ or AgNO₃ as an Oxidant was written by Zha, Gao-Feng;Bare, Grant A. L.;Leng, Jing;Shang, Zhen-Peng;Luo, Zhixiong;Qin, Hua-Li. And the article was included in Advanced Synthesis & Catalysis in 2017.HPLC of Formula: 1072951-54-2 This article mentions the following:

A practical oxidative Heck reaction between organoboronic acids and ethenesulfonyl fluoride (ESF) was developed. Aryl- and heteroaryl-boronic acids reacted efficiently and stereoselectively with ESF in the presence of a catalytic amount of Pd(OAc)₂ and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) or AgNO₃ in AcOH to afford the corresponding E-isomer of β-arylethenesulfonyl fluoride products. The utility of this reaction was exemplified by an expanded scope of 47 examples including N-, O-, and S-containing heteroaromatics, demonstrating chemoselectivity over aryliodides and gram-scale operation without the requirement for strict anhydrous or oxygen-free conditions. Furthermore, this procedure discriminated against the formation of arylboronic acids homo-coupling byproducts. In addition, the preparation of the first aryl vinylsulfonate polymer, a material with functionalizable Michael acceptor sites, from a starting arylboronic acid was described. In the experiment, the researchers used many compounds, for example, (2,6-Dichloropyridin-4-yl)boronic acid (cas: 1072951-54-2HPLC of Formula: 1072951-54-2).

(2,6-Dichloropyridin-4-yl)boronic acid (cas: 1072951-54-2) 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. 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. HPLC of Formula: 1072951-54-2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem