Day: October 14, 2022

Xu, Si-Yu; Zhang, Rui; Zhang, Shu-Sheng; Feng, Chen-Guo published the artcile< Enantioselective synthesis of 3-aryl-phthalides through a nickel-catalyzed stereoconvergent cross-coupling reaction>, Recommanded Product: (S)-4-(tert-Butyl)-2-(5-(trifluoromethyl)pyridin-2-yl)-4,5-dihydrooxazole, the main research area is arylphthalide preparation enantioselective nickel catalyst; bromophthalide arylboronic acid Suzukimiiyaura crosscoupling reaction.

A nickel-catalyzed asym. Suzuki-Miyaura cross-coupling of racemic 3-bromo-phthalides and arylboronic acids was realized for the synthesis of diverse chiral 3-aryl-phthalides in moderate to excellent reaction yields. The reaction proceeded in a stereoconvergent manner and high enantioselectivities were observed for most examined examples. A number of functional groups like aldehyde, ester and bromide were well tolerated. Heteroaromatic boronic acids were also competent coupling partners in this reaction.

Organic & Biomolecular Chemistry published new progress about Arylboronic acids Role: RCT (Reactant), RACT (Reactant or Reagent). 1416819-91-4 belongs to class pyridine-derivatives, and the molecular formula is C13H15F3N2O, Recommanded Product: (S)-4-(tert-Butyl)-2-(5-(trifluoromethyl)pyridin-2-yl)-4,5-dihydrooxazole.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Miller, Susanne L.; Chotana, Ghayoor A.; Fritz, Jonathan A.; Chattopadhyay, Buddhadeb; Maleczka, Robert E. Jr.; Smith, Milton R. III published the artcile< C-H Borylation Catalysts that Distinguish Between Similarly Sized Substituents Like Fluorine and Hydrogen>, Product Details of C7H9BrN2, the main research area is aromatic compound carbon hydrogen bond activation borylation iridium catalyst; borane heteroaryl derivative preparation.

By modifying ligand steric and electronic profiles it is possible to C-H borylate ortho or meta to substituents in aromatic and heteroaromatic compounds, where steric differences between accessible C-H sites are small. Dramatic effects on selectivities between reactions using B2pin2 or 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (HBpin) are described for the 1st time. Judicious ligand and borane combinations give highly regioselective C-H borylations on substrates where typical borylation protocols afford poor selectivities.

Organic Letters published new progress about Boranes Role: SPN (Synthetic Preparation), PREP (Preparation) ((hetero)aromatic). 396092-82-3 belongs to class pyridine-derivatives, and the molecular formula is C7H9BrN2, Product Details of C7H9BrN2.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Keller, P. A. published the artcile< Product class 2: pyridinones and related systems>, Category: pyridine-derivatives, the main research area is review pyridinone preparation; pyridinethione preparation review; pyridineselenone preparation review; pyridinetellurone preparation review.

A review of methods to prepare pyridinones and related systems is presented. Synthetic methods include cyclization, aromatization, ring transformation, and substituent modification. The parent pyridinones are generally stable and are easily handled under standard laboratory conditions. The corresponding pyridinethiones are generally more reactive but have the advantage of generally requiring only standard laboratory equipment for their handling. The pyridineselenones are more reactive and the pyridinetellurones have not been comprehensively studied and characterized due to their reactivity and associated difficulty in production

Science of Synthesis published new progress about Aromatization. 86129-63-7 belongs to class pyridine-derivatives, and the molecular formula is C9H9Cl2NO2, Category: pyridine-derivatives.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Timmer, Brian J. J.; Kravchenko, Oleksandr; Liu, Tianqi; Zhang, Biaobiao; Sun, Licheng published the artcile< Off-Set Interactions of Ruthenium-bda Type Catalysts for Promoting Water-Splitting Performance>, COA of Formula: C7H7NO2, the main research area is ruthenium catalyst water splitting performance catalytic activity; homogeneous catalysis; kinetics; noncovalent interactions; ruthenium; water splitting.

O-O bond formation with Ru(bda)L2-type catalysts is well-known to proceed through a bimol. reaction pathway, limiting the potential application of these catalysts at low concentrations Herein, we achieved high efficiencies with mononuclear catalysts, with TOFs of 460±32 s-1 at high catalyst loading and 31±3 s-1 at only 1 μM catalyst concentration, by simple structural considerations on the axial ligands. Kinetic and DFT studies show that introduction of an off-set in the interaction between the two catalytic units reduces the kinetic barrier of the second-order O-O bond formation, maintaining high catalytic activity even at low catalyst concentrations The results herein furthermore suggest that π-π interactions may only play a minor role in the observed catalytic activity, and that asymmetry can also rationalize high activity observed for Ru(bda)(isoq)2 type catalysts and offer inspiration to overcome the limitations of 2nd order catalysis.

Angewandte Chemie, International Edition published new progress about Bond formation. 93-60-7 belongs to class pyridine-derivatives, and the molecular formula is C7H7NO2, COA of Formula: C7H7NO2.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Li, Ying; Du, Na; Song, Shue; Hou, Wanguo published the artcile< Adsorption of Cetylpyridinium Chloride at Silica Nanoparticle/Water Interfaces (II): Dependence of Surface Aggregation on Particle Size>, Quality Control of 123-03-5, the main research area is cetylpyridinium chloride silica nanoparticle adsorption water aggregation.

Herein, we report a thermodn. model that relates adsorption (aggregation) parameters of surfactants at solid/liquid interfaces with particle radius (r). The adsorption (aggregation) parameters include adsorption amounts, equilibrium constants (or the standard Gibbs free energy changes), the critical surface micelle concentration (csmc), and the average aggregation number of surface micelles (n). The model predicts the size-dependence of surface aggregation of surfactants, which is determined by the changes in the interfacial tension and the molar volume of surface components caused by adsorption. In addition, the adsorption of cetylpyridinium chloride (CPyCl), a cationic surfactant, on silica nanoparticles with different r (ca. 6-61 nm) was determined at 298 K and pH 4, showing an obvious size-dependence, consistent with the prediction of the model. With an increase in r, the adsorption isotherm changes from the double-plateau type to the Langmuir type, accompanied by the obvious changes of the adsorption parameters. The size-dependent adsorption data can be well described using the model equations, indicating that the model presented here is acceptable. In addition, the model can extract information on the interfacial tensions from adsorption data. We think that the model deepens the understanding of the aggregation phenomena of surfactants at solid/liquid interfaces.

Langmuir published new progress about Adsorption. 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

Grivas, Spiros; Ronne, Erik published the artcile< Synthesis of four isomeric imidazonaphthyridines; three novel ring systems>, HPLC of Formula: 55279-29-3, the main research area is imidazonaphthyridine; Friedlaender reaction creatinine aminopyridinecarbaldehyde.

The novel 2-amino-1-Me derivatives of imidazo[4,5-b][1,x]naphthyridine, for example, I and II, were prepared via the Friedlaender reaction from the corresponding aminopyridinecarbaldehydes and creatinine in 65-85% yields. The ring systems I, II and their isomers were not reported previously.

Journal of Chemical Research, Synopses published new progress about Friedlander synthesis. 55279-29-3 belongs to class pyridine-derivatives, and the molecular formula is C6H6N2O, HPLC of Formula: 55279-29-3.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Chen, Dandan; Zhao, Qunfei; Liu, Wen published the artcile< Discovery of caerulomycin/collismycin-type 2,2'-bipyridine natural products in the genomic era>, Reference of 366-18-7, the main research area is review caerulomycin collismycin bipyridine bioactive natural product genomic era; 2,2′-Bipyridine; Caerulomycin; Collismycin; Natural product discovery; Natural products.

A review. 2,2′-Bipyridine (2,2′-BP) is the unique mol. scaffold of the bioactive natural products represented by caerulomycins (CAEs) and collismycins (COLs). CAEs and COLs are highly similar in the chem. structures in which their 2,2′-BP cores typically contain a di- or tri-substituted ring A and an unmodified ring B. Here, we summarize the CAE and COL-type 2,2′-BP natural products known or hypothesized to date: (1) isolated using methods traditional for natural product characterization, (2) created by engineering the biosynthetic pathways of CAEs or COLs, and (3) predicted upon bioinformatics-guided genome mining. The identification of these CAE and COL-type 2,2′-BP natural products not only demonstrates the development of research techniques and methods in the field of natural product chem. but also reflects the general interest in the discovery of CAE and COL-type 2,2′-BP natural products.

Journal of Industrial Microbiology & Biotechnology published new progress about Bioinformatics. 366-18-7 belongs to class pyridine-derivatives, and the molecular formula is C10H8N2, Reference of 366-18-7.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Dunn, A. D. published the artcile< The addition of hydroxylamine to derivatives of halopyridine carboxylic acids>, Recommanded Product: Methyl 3-bromo-2-pyridinecarboxylate, the main research area is halopyridinecarboxylate hydroxylamine addition; pyridinecarboxylate halo hydroxylamine addition; halopyridinenitrile hydroxylamine cyclization; isoxazolopyridine.

Cyanopyridines I (R = Cl, R1 = cyano, R2 = H; R = cyano, R1 = Cl, R2 = H; R = H, R1 = cyano, R2 = Cl) reacted with a MeOH solution of NH2OH and MeONa to give isoxazolopyridines. Thus, I (R = Cl, R1 = cyano, R2 = H) gave isoxazolopyridine II. However, I (R = H, R1 = Cl, R2 = cyano) reacted with the same reagent to give I (R, R1, same, R2 = CONH2), and I (R = H, R1 = Br, R2 = cyano) gave I [R, R1, same, R2 = C(:NOH)NH2]. No bicyclic products were formed . Esters I (R = Cl, R1 = CO2Me, R2 = H) reacted with the same reagent to give the hydroxamic acids I (R, R2, same, R1 = CONHOH). Similarly esters I (R = CO2Me, R1 = Br, R2 = H; R= H, R1 = Br, R2 = CO2Me) also gave the corresponding hydroxamic acids.

Zeitschrift fuer Chemie published new progress about Cyclocondensation reaction. 53636-56-9 belongs to class pyridine-derivatives, and the molecular formula is C7H6BrNO2, Recommanded Product: Methyl 3-bromo-2-pyridinecarboxylate.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

de Miranda, Thiago M.; de Oliveira, Alan R.; Pereira, Juliano R.; da Silva, Jeferson G.; Lula, Ivana S.; Nascimento, Clebio S. Jr.; Denadai, Angelo M. L. published the artcile< Inclusion vs. micellization in the cethylpyridine chloride / β-cyclodextrin system: A structural and thermodynamic approach>, Synthetic Route of 123-03-5, the main research area is complexation micellization cethylpyridine chloride cyclodextrin structure thermodn.

In the present work we have performed a structural and thermodn. characterization of supramol. structures formed by interaction between cetylpyridinium chloride (CPC) surfactant and β-cyclodextrin (βCD), using several phys.-chem. methods. Initially, qual. CPC/βCD interactions in solid state were confirmed by FTIR and TGA/DTA. 2D NMR ROESY experiment showed strong correlations between hydrogens of βCD cavity with aromatic and aliphatic hydrogens of CPC, suggesting the existence of different complexes in solution This information was corroborated by structures assessed by computational approach and stoichiometric coefficient obtained by ITC (N = 1.45). ITC experiments (at constant concentration of CPC) also showed that host-guest complexation occur with very high binding constant (Kb = 38,300.0), and driven by enthalpy and entropy. However, as CPC is an amphiphilic mol., it is able to form micelles at critical micellar concentration close to 1 mM. In presence of βCD, it was observed that micellization was delayed, so that the cmc values increased according to the empiric equation: cmc = 1.02 + 0.5[βCD]. Moreover, thermodn. data obtained by combination of conductometric and isothermal calorimetry titrations showed that the presence of increasing concentrations of βCD causes an increase of free energy of micellization, specially by gradual reduction of entropy of micellization, due to the difficult of micelles encapsulate the inclusion compounds The overall study was rationalized in terms of competition between micellization vs. host-guest complexation.

Journal of Molecular Structure published new progress about Complexation enthalpy. 123-03-5 belongs to class pyridine-derivatives, and the molecular formula is C21H38ClN, Synthetic Route of 123-03-5.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Jeon, Jinwon; He, Yu-Tao; Shin, Sanghoon; Hong, Sungwoo published the artcile< Visible-Light-Induced ortho-Selective Migration on Pyridyl Ring: Trifluoromethylative Pyridylation of Unactivated Alkenes>, COA of Formula: C7H7NO2, the main research area is phosphine oxide pyridinyl preparation; pyridinium alkenyloxy alkenylamino preparation trifluoromethylation phosphinylation regioselective migration; fluoroalkyl functionalized pyridine preparation; alkenes; heterocycles; photochemistry; radicals; reaction mechanisms.

The photocatalyzed ortho-selective migration on a pyridyl ring has been achieved for the site-selective trifluoromethylative pyridylation of unactivated alkenes. The overall process was initiated by the selective addition of a CF3 radical to the alkene moiety of N-(alkenyloxy)pyridinium salts I [X = O, Z = (CH2)3, R1 = H, 2-Me, 3-MeO2C, 4-Ph, etc., R2 = H, Me; X = O, Z = CH2, CH2CH2, (CH2)4, R1 = 4-MeO2C, R2 = H; X = NTs, Z = CH2, CH2CH2, R1 = H, 4-MeO2C, R2 = H; etc.] to provide a nucleophilic alkyl radical intermediate, which enabled an intramol. endo addition exclusively to the ortho-position of the pyridinium salt to afford the corresponding functionalized pyridines II. Both secondary and tertiary alkyl radicals were well-suited for addition to the C2-position of pyridinium salts to ultimately provide synthetically valuable C2-fluoroalkyl functionalized pyridines. Moreover, the method was successfully applied to the reaction with P-centered radicals. The utility of this transformation was further demonstrated by the late-stage functionalization of complex bioactive mols.

Angewandte Chemie, International Edition published new progress about Alkenes Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 93-60-7 belongs to class pyridine-derivatives, and the molecular formula is C7H7NO2, COA of Formula: C7H7NO2.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem