Day: December 7, 2022

Vogt, Matthias published the artcileAnionic Nickel(II) Complexes with Doubly Deprotonated PNP Pincer-Type Ligands and Their Reactivity toward CO₂, Category: pyridine-derivatives, the publication is Organometallics (2013), 32(1), 300-308, database is CAplus.

The aromatization-dearomatization reaction of pincer-type complexes prompted by protonation-deprotonation of the pincer “arm” is a key step in bond activation chem. and atom-economic catalytic transformations. However, the possibility of double deprotonation of ancillary pincer ligands is rarely discussed in the literature. Here authors report on square-planar cationic nickel(II) complexes of PNP^R type ligands (PNP = 2,6-bis[(dialkylphosphino)methyl]pyridine with R = ⁱPr, ^tBu), which can be readily transformed into the doubly deprotonated anionic species. The complexes [Ni(PNP^R)Cl]Cl (3, R = ⁱPr; 4, R = ^tBu) are readily prepared from the reaction of NiCl₂·6H₂O and the PNP^R ligand in THF. Treatment of the cationic chloro complexes 3 and 4 with 2 equivalent of MeLi gives the nickel(II) Me complexes [Ni(PNP^R*)Me] (7, R = ⁱPr; 8, R = ^tBu), the asterisk indicates the deprotonated pincer arm. Reaction of 7 and 8 with an addnl. 1 equivalent of MeLi gives the anionic complexes [Li(DME)₃][Ni(PNP^iPr**)Me] (9-DME, DME = 1,2-dimethoxyethane) and [Li(Et₂O)₂][Ni(PNP^tBu**)(Me)] (10-Et₂O), resp. Single-crystal x-ray diffraction studies exhibit doubly deprotonated PNP-pincer ligands coordinated to a nickel(II) center. DFT calculations, as well as multinuclear NMR spectroscopy and the x-ray structures, suggest a conjugated π-system with delocalization of the neg. charge throughout the carbon backbone of the pincer ligand. The electrophilic attack of complex 9 by CO₂ and tautomerization gives [Li][Ni(PNP^iPr*-COO)(Me)] (11). The dearomatized complex that is formed contains an exocyclic methylene carbon atom and a carboxylate moiety adjacent to the second pincer arm.

Organometallics published new progress about 338800-13-8. 338800-13-8 belongs to pyridine-derivatives, auxiliary class Bis-phosphine Ligands, name is 2,6-Bis((di-tert-butylphosphino)methyl)pyridine, and the molecular formula is C21H20BrNO4S, Category: pyridine-derivatives.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Henrick, C. A. published the artcilePyridinium ylides in synthesis. II. Acylation and the synthesis of β-dicarbonyl compounds, Safety of 1-(Cyanomethyl)pyridin-1-ium chloride, the publication is Australian Journal of Chemistry (1967), 20(11), 2455-65, database is CAplus.

The acylation of N-pyridinium ylides with acid chlorides or anhydrides yields C-acylated ylides which may be reductively cleaved to yield β-diketones or β-keto esters, depending on the starting materials. The uv, ir, and N.M.R. spectra of the ylides are discussed. 34 references.

Australian Journal of Chemistry published new progress about 17281-59-3. 17281-59-3 belongs to pyridine-derivatives, auxiliary class Pyridine,Nitrile,Salt, name is 1-(Cyanomethyl)pyridin-1-ium chloride, and the molecular formula is C7H7ClN2, Safety of 1-(Cyanomethyl)pyridin-1-ium chloride.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Grimstrup, Marie published the artcileNovel selective thiazoleacetic acids as CRTH2 antagonists developed from in silico derived hits. Part 2, Safety of (6-Amino-5-methylpyridin-3-yl)boronic acid, the publication is Bioorganic & Medicinal Chemistry Letters (2010), 20(3), 1181-1185, database is CAplus and MEDLINE.

Structure-activity relationships have been established by exploring the eastern and western side of 5-thiazolyleacetic acids as CRTH2 (chemoattractant receptor-homologous mol. expressed on Th2 cells) antagonists. Benzhydryl motifs in the 2-position of the thiazole was found to be most advantageous. The 4-thiazole position should either carry 3- or 4-fluorophenyl rings or a 4-pyridyl suitably substituted in the flanking 2-position. Several compounds with single digit nanomolar binding affinity and full antagonistic efficacy for human CRTH2 receptor were obtained. The compound series display a good PK profile and selectivity over a large number of other targets.

Bioorganic & Medicinal Chemistry Letters published new progress about 1032759-01-5. 1032759-01-5 belongs to pyridine-derivatives, auxiliary class Boronic acid and ester,Boronic acid and ester, name is (6-Amino-5-methylpyridin-3-yl)boronic acid, and the molecular formula is C6H9BN2O2, Safety of (6-Amino-5-methylpyridin-3-yl)boronic acid.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Profft, E. published the artcileThe preparation of 4-halo-2-methylpyridines, SDS of cas: 18437-58-6, the publication is Journal fuer Praktische Chemie (Leipzig) (1959), 164-72, database is CAplus.

Diazotization of 2-methyl-4-aminopyridine (I) (Boekelheide, C.A. 49, 5256f) with HBr and NaNO₂ at -15°, decomposition of the diazonium salt by bringing slowly to room temperature, addition of aqueous NaOH, and steam distillation gave 72% 2-methyl-4-bromopyridine (II), b. 184°, b₁₄74-6°, n²⁰_D 1.5542. II treated with MeI in C₆H₆ 10 hrs. at room temperature gave the methiodide, m. 214° (decomposition); II picrate m. 186°. II, AcOH, and H₂O₂ gave 55% 2-methyl-4-bromopyridine N-oxide (III), b₁₄ 178°, also prepared from 2-methyl-4-nitropyridine N-oxide and HBr in an autoclave at 160° (Suzuki, C.A. 47, 8074b). III was reduced to II by powd. Fe in AcOH at 100°. II.HCl and Reinecke salt in H₂O gave on standing II reineckate, m. 152-3°. From I, dilute H₂SO₄, and NaNO₂ at -15°, followed by addition of cold aqueous KI, warming to room temperature, addition of NaOH, and extraction with Et₂O was obtained 52% 2-methyl-4-iodopyridine (IV), b₁₄ 84-6°, m. 42°; picrate, yellow, decomposed 209°; reineckate m. 156-7°; methiodide m. 238° (decomposition). IV, AcOH, and H₂O₂ gave 2-methyl-4-iodopyridine N-oxide, b₁₄ 192-4°. I with HBF₄ and NaNO₂ at -15° followed by warming, NaOH addition, and steam distillation gave 43% 2-methyl-4-fluoropyridine (V), b. 128-32°, n²⁰_D 1.4713, more easily soluble in H₂O than the Br and iodo analogs; V picrate m. 152°; reineckate m. 158-9°; methiodide m. 191°; N-oxide (made by both methods shown for III) b₁₄ 136-8°. IV (5 g.) refluxed at 210° with 10 g. powd. Cu gave a solid mass, which ground in a mortar, extracted with 2N HCl, the solution neutralized with NaOH, extracted with Et₂O, and the extract evaporated gave 52% 2,2′-dimethyl-4,4′-bipyridyl, yellowish, m. 83°; picrate, yellow, decompose 237°.

Journal fuer Praktische Chemie (Leipzig) published new progress about 18437-58-6. 18437-58-6 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 4-Amino-2-picoline, and the molecular formula is C6H8N2, SDS of cas: 18437-58-6.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Brook, David J. R. published the artcileStrong ferromagnetic metal-ligand exchange in a nickel bis(3,5-dipyridylverdazyl) complex, Recommanded Product: 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, the publication is Chemical Communications (Cambridge, United Kingdom) (2010), 46(35), 6590-6592, database is CAplus and MEDLINE.

A new 1,5-dipyridyl verdazyl, synthesized from the corresponding dipyridyl hydrazone, coordinates nickel(II) to form a structurally characterized, pseudooctahedral complex analogous to Ni(terpy)₂²⁺. The unusually short Ni-verdazyl distance results in strong ferromagnetic exchange (J_Ni-rad = +300, J_rad-rad = +160 cm^-1) between all three paramagnetic species along with a metal-ligand charge transfer band in the electronic spectrum.

Chemical Communications (Cambridge, United Kingdom) published new progress about 2215-33-0. 2215-33-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, and the molecular formula is C11H10N4, Recommanded Product: 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Verheijen, Jeroen C. published the artcileDiscovery of 4-Morpholino-6-aryl-1H-pyrazolo[3,4-d]pyrimidines as Highly Potent and Selective ATP-Competitive Inhibitors of the Mammalian Target of Rapamycin (mTOR): Optimization of the 6-Aryl Substituent, Name: (6-Hydroxypyridin-3-yl)boronic acid, the publication is Journal of Medicinal Chemistry (2009), 52(24), 8010-8024, database is CAplus and MEDLINE.

Design and synthesis of a series of 4-morpholino-6-aryl-1H-pyrazolo[3,4-d]pyrimidines, e.g. I, as potent and selective inhibitors of the mammalian target of rapamycin (mTOR) are described. Optimization of the 6-aryl substituent led to the discovery of inhibitors carrying 6-ureidophenyl groups, the first reported active site inhibitors of mTOR with subnanomolar inhibitory concentrations The data presented in this paper show that 6-arylureidophenyl substituents led to potent mixed inhibitors of mTOR and phosphatidylinositol 3-kinase α (PI3K-α), whereas 6-alkylureidophenyl appendages gave highly selective mTOR inhibitors. Combination of 6-alkylureidophenyl groups with 1-carbamoylpiperidine substitution resulted in compounds with subnanomolar IC₅₀ against mTOR and greater than 1000-fold selectivity over PI3K-α. In addition, structure based drug design resulted in the preparation of several 6-arylureidophenyl-1H-pyrazolo[3,4-d]pyrimidines, substituted in the 4-position of the arylureido moiety with water solubilizing groups. These compounds combined potent mTOR inhibition (IC₅₀ < 1 nM) with unprecedented activity in cellular proliferation assays (IC₅₀ < 1 nM).

Journal of Medicinal Chemistry published new progress about 903899-13-8. 903899-13-8 belongs to pyridine-derivatives, auxiliary class Pyridine,Boronic acid and ester,Alcohol,Boronic Acids,Boronic acid and ester, name is (6-Hydroxypyridin-3-yl)boronic acid, and the molecular formula is C6H8O3, Name: (6-Hydroxypyridin-3-yl)boronic acid.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Lavit, Kseniya published the artcileZooming in on the hydrated imidazoline ring expansion: Factors influencing the rate of N â†?N’ aroyl migration in N-aroyl-N-(hetero)aryl ethylenediamines, Related Products of pyridine-derivatives, the publication is Tetrahedron Letters (2020), 61(42), 152423, database is CAplus.

The influence of electronic factors on the rates of N â†?N’ aroyl migration in N-aroyl-N-(hetero)aryl ethylenediamines was examined Electron-withdrawing substituents on the aroyl group weakly accelerate the reaction (in linear correlation with the Hammett σ_p constants). Much stronger influence came from the nitrogen-bound aromatic group which gave a strong linear correlation with the Hammett σ^–_p constants For electron-deficient heteroaromatics and nitroaroms., the migration was nearly instantaneous in basic medium. These findings will significantly impact the planning of mechanistically related transformations of N-(2-aminoethyl) lactams through the hydrated imidazoline ring expansion (HIRE) process.

Tetrahedron Letters published new progress about 197958-29-5. 197958-29-5 belongs to pyridine-derivatives, auxiliary class Pyridine,Boronic acid and ester, name is 2-Pyridinylboronic acid, and the molecular formula is C5H6BNO2, Related Products of pyridine-derivatives.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Ramya, G. published the artcileInvestigations on pyridine-3-sulfonic acid doped polyaniline and polypyrrole: Metal loading through dopant molecules, Safety of Pyridine-3-sulfonic acid, the publication is Reactive & Functional Polymers (2008), 68(3), 701-709, database is CAplus.

Polyniline and polypyrrole were chem. and electrochem. synthesized in presence of pyridine-3-sulfonic acid. These conducting polymers were characterized by FT-IR, UV-vis, XRD, TGA and SEM techniques. Polyaniline showed a conductivity of 4 × 10^-4 S/cm while polypyrrole exhibited a conductivity of 6.2 × 10^-2 S/cm. The presence of pyridine ring in the dopant enabled the polymers to anchor Pd/or PdO through which the composite can work as catalytic material.

Reactive & Functional Polymers published new progress about 636-73-7. 636-73-7 belongs to pyridine-derivatives, auxiliary class Pyridine,Sulfonic acid, name is Pyridine-3-sulfonic acid, and the molecular formula is C5H5NO3S, Safety of Pyridine-3-sulfonic acid.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Hegde, V. B. published the artcileA general and versatile synthesis of 2-alkyl-4-aminopyridines, Category: pyridine-derivatives, the publication is Tetrahedron Letters (2001), 42(10), 1847-1849, database is CAplus.

A versatile 2-step synthesis of 2-alkyl-4-pyridinamines from com. available cis-1-methoxy-1-buten-3-yne is described. Acylation of the alkyne followed by amination and cyclization in NH₃ produced the desired substituted pyridines in high yield.

Tetrahedron Letters published new progress about 18437-58-6. 18437-58-6 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 4-Amino-2-picoline, and the molecular formula is C6H8N2, Category: pyridine-derivatives.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Panchaud, Philippe published the artcile3-Pyridinesulfonyl azide: A useful reagent for radical azidation, Name: Pyridine-3-sulfonic acid, the publication is Advanced Synthesis & Catalysis (2004), 346(8), 925-928, database is CAplus.

Radical azidations and carboazidations have been achieved using 3-pyridinesulfonyl azide as azidating agent. Due to its base properties and its polarity, the excess of reagent is readily removed at the end of the reaction by filtration through silica gel or by extraction with either aqueous 1M HCl or 1M CuSO₄. The use of this reagent greatly facilitates the tedious purifications of the final azides frequently encountered when reactions are run according to the original procedure involving benzenesulfonyl azide. Thus, reaction of Et 2-iodoacetate with 1-octene in presence of Bu₆Sn₂/di-tert-Bu hyponitrite/3-pyridinesulfonyl azide in C₆H₆ gave 80% Et 4-azidodecanoate.

Advanced Synthesis & Catalysis published new progress about 636-73-7. 636-73-7 belongs to pyridine-derivatives, auxiliary class Pyridine,Sulfonic acid, name is Pyridine-3-sulfonic acid, and the molecular formula is C5H5NO3S, Name: Pyridine-3-sulfonic acid.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem