Category: pyridine-derivatives

Hopkins, Cameron C.; Haward, Simon J.; Shen, Amy Q. published the artcile< Upstream wall vortices in viscoelastic flow past a cylinder>, SDS of cas: 123-03-5, the main research area is cetylpyridinium chloride sodium salicylate viscoelastic flow rheol property.

We report a novel inertia-less, elastic flow instability for a viscoelastic, shear-thinning wormlike micellar solution flowing past a microcylinder in a channel with blockage ratio BR = 2R/W = 0.5 and aspect ratio α = H/W ≈5, where R ∼ 100μm is the cylinder radius, W is the channel width, and H is the channel height. The instability manifests upstream of the cylinder and changes form with increasing Weissenberg number over the range 0.5 ≤ Wi = Uλ/R ≤ 900, where U is the average flow velocity and λ is the terminal relaxation time of the fluid. Beyond a first critical Wi, the instability begins as a bending of the streamlines near the upstream pole of the cylinder that breaks the symmetry of the flow. Beyond a second critical Wi, small, time-steady, and approx. sym. wall-attached vortices form upstream of the cylinder. Beyond a third critical Wi, the flow becomes time dependent and pulses with a characteristic frequency commensurate with the breakage timescale of the wormlike micelles. This is accompanied by a breaking of the symmetry of the wall-attached vortices, where one vortex becomes considerably larger than the other. Finally, beyond a fourth critical Wi, a vortex forms attached to the upstream pole of the cylinder whose length fluctuates in time. The flow is highly time dependent, and the cylinder-attached vortex and wall-attached vortices compete dynamically for space and time in the channel. Our results add to the rapidly growing understanding of viscoelastic flow instabilities in microfluidic geometries.

Soft Matter published new progress about Dynamic viscosity. 123-03-5 belongs to class pyridine-derivatives, and the molecular formula is C21H38ClN, SDS of cas: 123-03-5.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Carrouel, F.; Goncalves, L. S.; Conte, M. P.; Campus, G.; Fisher, J.; Fraticelli, L.; Gadea-Deschamps, E.; Ottolenghi, L.; Bourgeois, D. published the artcile< Antiviral Activity of Reagents in Mouth Rinses against SARS-CoV-2>, Computed Properties of 123-03-5, the main research area is antiviral activity reagent mouth rinses against SARSCoV2 review; COVID-19; clinical trial; mouthwashes; oral; saliva; viral load.

A review. The oral cavity, an essential part of the upper aerodigestive tract, is believed to play an important role in the pathogenicity and transmission of SARS-CoV-2. The identification of targeted antiviral mouth rinses to reduce salivary viral load would contribute to reducing the COVID-19 pandemic. While awaiting the results of significant clin. studies, which to date do not exist, the com. availability of mouth rinses leads us to search among them for reagents that would have specific antiviral properties with respect to SARS-CoV-2. The challenges facing this target were examined for 7 reagents found in com. available mouth rinses and listed on the ClinicalTrials.gov website: povidone-iodine, chlorhexidine, hydrogen peroxide, cyclodextrin, Citrox, cetylpyridinium chloride, and essential oils. Because SARS-CoV-2 is an enveloped virus, many reagents target the outer lipid membrane. Moreover, some of them can act on the capsid by denaturing proteins. Until now, there has been no scientific evidence to recommend mouth rinses with an anti-SARS-CoV-2 effect to control the viral load in the oral cavity. This critical review indicates that current knowledge of these reagents would likely improve trends in salivary viral load status. This finding is a strong sign to encourage clin. research for which quality protocols are already available in the literature.

Journal of Dental Research published new progress about Antiviral agents. 123-03-5 belongs to class pyridine-derivatives, and the molecular formula is C21H38ClN, Computed Properties of 123-03-5.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Yang, Xiao; Sun, Rui; Zhang, Chunchun; Zhang, Yan; Su, Zhishan; Ge, Yicen; Chen, Hua; Fu, Haiyan; Li, Ruixiang published the artcile< Chichibabin-Type Phosphonylation of 2-(Hetero)aryl Pyridines: Selective Synthesis of 4-Phosphinoyl Pyridines via an Activated N-Benzylpyridinium Salt>, Related Products of 350-03-8, the main research area is Chichibabin phosphinylation phosphonylation benzylpyridinium hydrophosphonate preparation pyridylphosphine oxide pyridylphosphonate; metal free base catalyzed regioselective phosphinylation benzylpyridinium hydrophosphonate; potential energy surface mechanism phosphinylation phosphonylation benzylpyridinium hydrophosphonate.

A direct C-H phosphonylation of 2-aryl-N-benzylpyridinium salts by N-benzylating activation is reported, which afforded 4-pyridylphosphine oxides with high regioselectivity, without the employment of metal catalyst or expensive activator. By increasing the electrophilicity of pyridinium with electron-withdrawing substituents on the N-benzyl group, the phosphonylation process could be realized at room temperature Control experiments and NMR investigation confirmed the interaction between DBU and diphenylphosphine oxide which generated the true phosphorus nucleophile. Moreover, DFT calculations offered enough insight into an intermol. cooperative dehydrogenation-debenzylation mechanism, which helped to elucidate the origin of C4-regioselectivity in this metal-free Chichibabin-type phosphonylation.

Advanced Synthesis & Catalysis published new progress about Benzylation. 350-03-8 belongs to class pyridine-derivatives, and the molecular formula is C7H7NO, Related Products of 350-03-8.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Caron, Stephane; Do, Nga M.; Sieser, Janice E.; Whritenour, David C.; Hill, Paul D. published the artcile< Preparation of a Corticotropin-Releasing Factor Antagonist by Nucleophilic Aromatic Substitution and Copper-Mediated Ether Formation>, Formula: C9H9Cl2NO2, the main research area is butylamino aryloxy nicotinate preparation process development drug candidate; corticotropin releasing factor antagonist preparation process development drug candidate; nucleophilic aromatic substitution ether formation copper drug candidate preparation.

Several synthetic approaches to a corticotropin-releasing factor (CRF) antagonist containing a tetrasubstituted pyridine (I) were evaluated. In particular, nucleophilic aromatic substitutions on 2,4-dichloropyridine derivatives were attempted using 2,6-dimethyl-4-chlorophenol, (S)-2-aminobutanol, and several sulfur nucleophiles. It was found that a copper-mediated coupling of a phenoxymesylate was preferred for preparation of the diarylether followed by nucleophilic aromatic substitution to introduce the amine side chain, affording the desired drug candidate (I) in two steps from the com. available Me 2,4-dichloro-6-methylnicotinate.

Organic Process Research & Development published new progress about Etherification. 86129-63-7 belongs to class pyridine-derivatives, and the molecular formula is C9H9Cl2NO2, Formula: C9H9Cl2NO2.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Wu, Shijian; Mohammadigoushki, Hadi published the artcile< Linear versus branched: flow of a wormlike micellar fluid past a falling sphere>, Quality Control of 123-03-5, the main research area is linear branched microstructure micellar fluid flow falling sphere.

We report experiments on flow of wormlike micellar solutions past a falling sphere. By increasing the salt-to-surfactant concentration ratio, and beyond a viscosity peak, wormlike micelles experience a transition from linear to branched microstructure. Two viscoelastic wormlike micelles with salt to surfactant concentrations on each side of the viscosity peak are considered. Our results indicate three significant differences in flows of branched and linear micelles. First, while the sphere drag correction factor rapidly decreases upon increasing Weissenberg number in linear micelles, it shows an apparent local maximum at Wi ≈ 3 in branched micelles. Second, despite its high viscoelasticity, the time-averaged flow of branched micelles around the falling sphere exhibits a fore-and-aft symmetry, while a strong neg. wake is observed in linear micelles at relatively weaker flows. Third, branched micelles exhibit a stronger flow-induced birefringence than linear micelles in an otherwise identical condition. Our hypothesis is that subject to strong flows around the falling sphere, branched micelles can relax much more efficiently than linear wormlike micelles through sliding of the branched junctions. This addnl. stress relaxation mechanism may facilitate micellar orientation, produce a marginal sphere drag reduction and a Newtonian-like flow profile around the falling sphere. Finally, unsteady flow is observed in both linear and branched micellar solutions beyond some critical thresholds of the extensional Weissenber number Our results corroborate a recently proposed criterion for onset of instability in flow of wormlike micelles past a falling sphere, thereby, suggesting that micellar branching does not affect the mechanism of flow instability.

Soft Matter published new progress about Dimensionless number, Weissenberg. 123-03-5 belongs to class pyridine-derivatives, and the molecular formula is C21H38ClN, Quality Control of 123-03-5.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Sokolov, V. B.; Aksinenko, A. Yu. published the artcile< Fluorinated triazinones from hexafluoroacetone ethoxycarbonylimine>, SDS of cas: 188577-68-6, the main research area is hexafluoroacetone ethoxycarbonylimine cyclocondensation binucleophile; trifluoromethyltriazinone derivative preparation.

The behavior of hexafluoroacetone ethoxycarbonylimine in cyclocondensation with various binucleophiles of the amidine type, viz., amino derivatives of N- and N,S-heterocycles, was studied. A preparative method for the synthesis of previously unknown annelated 2,2-bis(trifluoromethyl)-1,3,5-triazinones was developed.

Russian Chemical Bulletin (Translation of Izvestiya Akademii Nauk, Seriya Khimicheskaya) published new progress about Cyclocondensation reaction. 188577-68-6 belongs to class pyridine-derivatives, and the molecular formula is C5H4Cl2N2, SDS of cas: 188577-68-6.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

De Bon, Francesco; Abreu, Carlos M. R.; Serra, Armenio C.; Gennaro, Armando; Coelho, Jorge F. J.; Isse, Abdirisak A. published the artcile< Catalytic Halogen Exchange in Supplementary Activator and Reducing Agent Atom Transfer Radical Polymerization for the Synthesis of Block Copolymers>, Related Products of 1762-41-0, the main research area is halogen exchange activator reducing agent ATRP block copolymer; ATRP; block copolymerization; catalytic halogen exchange; copper catalyst; supplemental activator.

Synthesis of block copolymers (BCPs) by catalytic halogen exchange (cHE) is reported, using supplemental activator and reducing agent Atom Transfer Radical Polymerization (SARA ATRP). The cHE mechanism is based on the use of a small amount of a copper catalyst in the presence of a suitable excess of halide ions, for the synthesis of block copolymers from macroinitiators with monomers of mismatching reactivity. cHE overcomes the problem of inefficient initiation in block copolymerizations in which the second monomer provides dormant species that are more reactive than the initiator. Model macroinitiators with low dispersity are prepared and extended to afford well-defined block copolymers of various compositions Combined cHE/SARA ATRP is therefore a simple and potent polymerization tool for the copolymerization of a wide range of monomers allowing the production of tailored block copolymers.

Macromolecular Rapid Communications published new progress about Atom transfer radical polymerization catalysts. 1762-41-0 belongs to class pyridine-derivatives, and the molecular formula is C10H6Cl2N2, Related Products of 1762-41-0.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Mancuso, Raffaella; Novello, Mariangela; Russo, Patrizio; Palumbo Piccionello, Antonio; Gabriele, Bartolo published the artcile< Iodolactonization of 3-Alkynylthiophene-2-Carboxylic and 3-Alkynylpicolinic Acids for the Synthesis of Fused Heterocycles>, Name: Methyl 3-bromo-2-pyridinecarboxylate, the main research area is fused heterocycle preparation iodolactonization alkynylthiophenecarboxylate alkynylpicolinate.

The iodolactonization of 3-alkynylthiophene-2-carboxylic acids and 3-alkynylpicolinic acids was studied. Using I2 as the iodine source and NaHCO3 as the base in MeCN, the process took place smoothly to afford thienopyranones and pyranopyridinones, resp., from 6-endo-dig cyclization. The method also worked nicely for the transformation of 2-(phenylethynyl)thiophene-3-carboxylic acid and 3-(phenylethynyl)isonicotinic acid into 7-iodo-6-phenyl-4H-thieno[3,2-c]pyran-4-one and 4-iodo-3-phenyl-1H-pyrano[4,3-c]pyridin-1-one, resp. Although with some 3-alkynylpicolinic acids the process led to a mixture of the 6-endo-dig and 5-exo-dig products, it could be still made selective toward the pyranopyridinone compound working in 1-ethyl-3-methylimidazolium Et sulfate as the solvent. However, the exclusive formation of the 5-exo-dig product was observed in N-ethyl-N-methylmorpholinium dicyanamide starting from 3-(3,3-dimethylbut-1-yn-1-yl)picolinic acid. Some representative iodinated thienopyridinone products were successfully used as substrates for Pd-catalyzed Suzuki and Sonogashira reactions.

European Journal of Organic Chemistry published new progress about Carboxylic acids Role: RCT (Reactant), RACT (Reactant or Reagent) (3-Alkynylthiophene-2-Carboxylic Acids). 53636-56-9 belongs to class pyridine-derivatives, and the molecular formula is C7H6BrNO2, Name: Methyl 3-bromo-2-pyridinecarboxylate.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Pillalamarri, Vijaykumar; Reddy, Chilakala Gangi; Bala, Sandeep Chowdary; Jangam, Aruna; Kutty, Vinny Vinod; Addlagatta, Anthony published the artcile< Methionine aminopeptidases with short sequence inserts within the catalytic domain are differentially inhibited: Structural and biochemical studies of three proteins from Vibrio spp.>, Name: 2,2′-Bipyridine, the main research area is methionine aminopeptidase inhibitor drug target; Cholera; Drug discovery; MetAP; Methionine aminopeptidase; Vibrio.

Methionine aminopeptidases (MetAPs) have been recognized as drug targets and have been extensively studied for discovery of selective inhibitors. MetAPs are essential enzymes in all living cells. While most prokaryotes contain a single gene, some prokaryotes and all eukaryotes including human have redundancy. Due to the similarity in the active sites of the MetAP enzyme between the pathogens and human limited the success of discovering selective inhibitors. We recently have discovered that MetAPs with small inserts within the catalytic domain to have different susceptibilities against some inhibitors compared to those that do not have. Using this clue we used bioinformatic tools to identify new variants of MetAPs with inserts in pathogenic species. Two new isoforms were identified in Vibrio species with two and three inserts in addition to an isoform without any insert. Multiple sequence alignment suggested that inserts are conserved in several of the Vibrio species. Two of the three inserts are common between two and three insert isoforms. One of the inserts is identified to have “”NNKNN”” motif that is similar to well-characterized quorum sensing peptide, “”NNWNN””. Another insert is predicted to have a posttranslational modification site. Three Vibrio proteins were cloned, expressed, purified, enzyme kinetics established and inhibitor screening has been performed. Several of the pyridinylpyrimidine derivatives selectively inhibited MetAPs with inserts compared to those that do not have, including the human enzyme. Crystal structure and mol. modeling studies provide the mol. basis for selective inhibition.

European Journal of Medicinal Chemistry published new progress about Crystal structure. 366-18-7 belongs to class pyridine-derivatives, and the molecular formula is C10H8N2, Name: 2,2′-Bipyridine.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Song, J. H.; Bae, S. M.; Lee, E. J.; Cho, J. H.; Jung, D. I. published the artcile< Formation of benzodiazepines and pyrazinylquinoxalines from aromatic and heteroaromatic ketones via deoximation>, Quality Control of 350-03-8, the main research area is benzodiazepine preparation; pyrazinylquinoxaline preparation.

In the course of present investigations, it was found that dichloroamine T could be an efficient reagent for the conversion of oximes into the corresponding carbonyl compounds Herein the synthesis of 1H-1,5-benzodiazepine derivatives I [R = pyrrol-2-yl, 2-pyridinyl, 2-thienyl, etc.] from heteroaromatic ketones and acetone equivalent was obtained using dichloroamine-T. On the other hand, when diamine (1,2-phenylene diamine or 1,2-naphthalene diamine) with heterocyclic ketone (acetyl pyridine or acetyl pyrazines) in the presence of concentrate HCl and SiO2 was refluxed, quinoxaline derivatives, II [R = 2-pyrazinyl, 2-pyridinyl, 2-thienyl, etc.] as yellow crystalline solids were isolated in high yields.

Asian Journal of Chemistry published new progress about Benzodiazepines Role: SPN (Synthetic Preparation), PREP (Preparation). 350-03-8 belongs to class pyridine-derivatives, and the molecular formula is C7H7NO, Quality Control of 350-03-8.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem