Tag: M.W=300-350

Hu, Xiangfei published the artcileOxidative stabilities of grass carp oil: possible mechanisms of volatile species formation in hydroperoxylated metabolites at high temperature, Related Products of catalysis-chemistry, the publication is European Food Research and Technology (2022), 248(8), 2079-2095, database is CAplus.

The mechanisms of volatile species formation for hydroperoxylated metabolites of unsaturated fatty acids in grass carp oil were investigated. All oil samples were heated at 110 ¡ãC for 8 various durations. The hydroperoxylated metabolites were evaluated by ultra-performance liquid chromatog. coupled with time-of-flight mass spectrometry, solid-phase microextraction gas chromatog. mass spectrometry and conventional chem. indicators. Compared to fresh fish oil, the content of monounsaturated fatty acids and saturated fatty acids with higher oxidation stability in the heating samples was significantly increased (P < 0.05), while the content of polyunsaturated fatty acids was significantly reduced (P < 0.05). A total of 35 triglycerides were determined, of these, the relative content of carbon numbers (CNs) 54, 56 and 58 was dramatically decreased, while CN50 and CN52 were gradually increased. Partial least-squares discriminant anal. indicated that continuous heating had different effects on volatile substances and twelve volatile species variables associated with lipid oxidation from the eight various heating periods were identified. In addition, sixteen oxidized metabolites were identified and their content was significantly increased (P < 0.05), except the 13-HODE, 9-HOTrE, 5-HETE and 12-HETE. The metabolic pathways of grass carp oil under continuous heating were clarified based on critical volatile components and oxidized metabolites, intending to reveal the oxidation paradigm of oil exposed to high temperatures

European Food Research and Technology published new progress about 6217-54-5. 6217-54-5 belongs to catalysis-chemistry, auxiliary class Alkenyl,Carboxylic acid,Aliphatic hydrocarbon chain,Metabolic Enzyme,RAR/RXR,Natural product, name is Docosahexaenoic Acid, and the molecular formula is C22H32O2, Related Products of catalysis-chemistry.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Moon, Byung Seok published the artcileHighly efficient production of [¹⁸F]fallypride using small amounts of base concentration, Recommanded Product: Tetrabutylammonium hydrogencarbonate, the publication is Applied Radiation and Isotopes (2010), 68(12), 2279-2284, database is CAplus and MEDLINE.

To minimize the base concentration of a phase-transfer catalyst, [¹⁸F]fluoride was extracted from ¹⁸O-enriched water trapped on an activated ion exchange cartridge (Chromafix PS-HCO₃) using different concentrations of tetrabutylammonium bicarbonate (TBAHCO₃) or Kryptofix 2.2.2./K₂CO₃ in organic solvents such as CH₃CN/H₂O or MeOH/H₂O. The optimal labeling condition for [¹⁸F]fallypride with automated synthesis was that 2 mg of tosyl-fallypride in acetonitrile (1 mL) was heated at 100 ¡ãC for 10 min using 40% TBAHCO₃ (10 ¦ÌL). [¹⁸F]Fallypride was obtained with a high radiochem. yield of approx. 68¡À1.6% (decay-corrected, n=42) with a total synthesis time of 51¡À1.2 min, including HPLC purification and solid-phase purification for the final formulation.

Applied Radiation and Isotopes published new progress about 17351-62-1. 17351-62-1 belongs to catalysis-chemistry, auxiliary class Salt,Amine, name is Tetrabutylammonium hydrogencarbonate, and the molecular formula is C17H37NO3, Recommanded Product: Tetrabutylammonium hydrogencarbonate.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Mooney, Ciaran R. S. published the artcileCrystallographic Snapshot of an Arrested Intermediate in the Biomimetic Activation of CO₂ [Erratum to document cited in CA162:197128], Recommanded Product: Tetrabutylammonium hydrogencarbonate, the publication is Angewandte Chemie, International Edition (2015), 54(26), 7470, database is CAplus and MEDLINE.

The authors believe that that a single crystal of [(n-C₄H₉)₄N]⁺[CH₃CO₂]^– impurity was misidentified as [(n-C₄H₉)₄N]⁺[O₂C¡¤¡¤¡¤OH]^–; a discussion is provided.

Angewandte Chemie, International Edition published new progress about 17351-62-1. 17351-62-1 belongs to catalysis-chemistry, auxiliary class Salt,Amine, name is Tetrabutylammonium hydrogencarbonate, and the molecular formula is C17H37NO3, Recommanded Product: Tetrabutylammonium hydrogencarbonate.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Manna, Surya Sekhar published the artcilePyrrolidinium-Based Organic Cation (BMP)-Intercalated Organic (Coronene) Anode for High-Voltage Dual-Ion Batteries: A Comparative Study with Graphite, Quality Control of 191-07-1, the publication is Journal of Physical Chemistry C (2022), 126(22), 9264-9274, database is CAplus.

Among the post-lithium-ion batteries, rechargeable dual-ion batteries (DIBs) have bright opportunities for the development of cheap and safe batteries possessing a good electrochem. performance. The DIBs with pure ionic liquid (IL) electrolytes featuring a high voltage, sustainability, and environmental friendliness have received attention from researchers. Owing to intercalation/deintercalation of large size IL cations, the conventional dual-graphite batteries (DGBs) have suffered from severe volume expansion, thus limiting the overall reversibility of the DGBs. Herein, we have modeled two DIBs, introducing an organic cation-intercalated polycyclic aromatic hydrocarbon anode (coronene) coupled with a graphite cathode and a DGB in the other case. Pyrrolidinium-based IL, N-butyl-N-Me pyrrolidinium chloride (BMP-Cl) with the AlCl₃ salt has been employed as an electrolyte. Applying the first-principles calculation, we have investigated the systematic intercalation of the BMP cation into the coronene and graphite anodes. The BMP-intercalated graphite anode shows a higher binding energy (2.36 eV) compared to that of the coronene anode (1.71 eV). In the fully charged state, a calculated discharge voltage of 3.1 and 3.05 V and a maximum capacity of 116 and 130 mA h g^-1 have been observed for the graphite coronene dual-ion battery (GCDIB) and DGB, resp. However, the percentage of volume expansion of the graphite anode is higher (148%) compared to that of the coronene anode (53%) upon a full intercalation of BMP cations, indicating more exfoliation-prone nature of graphite compared to coronene. The d. of states and Bader charge anal. reveal that the BMP cation is intercalated successfully, indicating a reduction of electrode materials during the charging process. Furthermore, we have explained the merits of choosing the AlCl₄ anion compared to other commonly used anions such as TFSI in DIBs. These results support a clear understanding of BMP cation intercalation into both coronene and graphite anodes and motivate the fabrication of a new class of low-cost organic anode DIBs with an optimum electrochem. performance.

Journal of Physical Chemistry C published new progress about 191-07-1. 191-07-1 belongs to catalysis-chemistry, auxiliary class Electronic Materials, name is Coronene, and the molecular formula is C24H12, Quality Control of 191-07-1.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Paquette, Andre R. published the artcileRpoN-Based stapled peptides with improved DNA binding suppress Pseudomonas aeruginosa virulence, Application In Synthesis of 71989-31-6, the publication is RSC Medicinal Chemistry (2022), 13(4), 445-455, database is CAplus and MEDLINE.

Stapled peptides have the ability to mimic ¦Á-helixes involved in protein binding and have proved to be effective pharmacol. agents for disrupting protein-protein interactions. DNA-binding proteins such as transcription factors bind their cognate DNA sequences via an ¦Á-helix interacting with the major groove of DNA. We previously developed a stapled peptide based on the bacterial alternative sigma factor RpoN capable of binding the RpoN DNA promoter sequence and inhibiting RpoN-mediated expression in Escherichia coli. We have elucidated a structure-activity relationship for DNA binding by this stapled peptide, improving DNA binding affinity constants in the high nM range. Lead peptides were shown to have low toxicity as determined by their low hemolytic activity at 100 ¦ÌM and were shown to have anti-virulence activity in a Galleria mellonella model of Pseudomonas aeruginosa infection. These findings support further preclin. development of stapled peptides as antivirulence agents targeting P. aeruginosa.

RSC Medicinal Chemistry published new progress about 71989-31-6. 71989-31-6 belongs to catalysis-chemistry, auxiliary class Amino acide derivatives,pyrrolidine, name is Fmoc-Pro-OH, and the molecular formula is C20H19NO4, Application In Synthesis of 71989-31-6.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Vanjari, Rajeshwer published the artcileGold(I)-mediated rapid cyclization of propargylated peptides via imine formation, Category: catalysis-chemistry, the publication is Journal of the American Chemical Society (2022), 144(11), 4966-4976, database is CAplus and MEDLINE.

In fundamental research and drug discovery, there is still a need for effective and straightforward chem. approaches for generating cyclic peptides. The divergent synthesis of cyclic peptides remains a challenge, in particular when cyclization is carried out in the presence of unprotected side chains and a nonpeptidic component within the cycle is needed. Herein, we describe a novel and efficient strategy based on Au(I)-mediated cyclization of unprotected peptides through rapid (30-60 min) amine addition on a propargyl group to generate an imine linkage. Mechanistic insights reveal that the reaction proceeds via regioselective Markovnikov’s addition of the amine on the Au(I)-activated propargyl. This strategy was successfully applied to prepare efficiently (56-94%) over 35 diverse cyclic peptides having different sequences and lengths. We have also achieved stereoselective reduction of cyclic imines employing chiral ligands. The practicality of our method was extended for the synthesis of cyclic peptides that bind Lys48-linked di-ubiquitin chains with high affinity, leading to apoptosis of cancer cells.

Journal of the American Chemical Society published new progress about 71989-31-6. 71989-31-6 belongs to catalysis-chemistry, auxiliary class Amino acide derivatives,pyrrolidine, name is Fmoc-Pro-OH, and the molecular formula is C13H19N5OS, Category: catalysis-chemistry.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Handoko published the artcileTwo-component redox organocatalyst for peptide bond formation, COA of Formula: C20H19NO4, the publication is Journal of the American Chemical Society (2022), 144(8), 3637-3643, database is CAplus and MEDLINE.

Peptides are fundamental therapeutic modalities whose sequence-specific synthesis can be automated. Yet, modern peptide synthesis remains atom uneconomical and requires an excess of coupling agents and protected amino acids for efficient amide bond formation. We recently described the rational design of an organocatalyst that can operate on Fmoc (Fmoc = 9-fluorenylmethoxycarbonyl) amino acids-the standard monomers in automated peptide synthesis (J.Am.Chem.Soc.2019, 141, 15977). The catalytic cycle centered on the conversion of the carboxylic acid to selenoester, which was activated by a hydrogen bonding scaffold for amine coupling. The selenoester was generated in situ from a diselenide catalyst and stoichiometric amounts of phosphine. Although the prior system catalyzed oligopeptide synthesis on solid phase, it had two significant requirements that limited its utility as an alternative to coupling agents-it depended on stoichiometric amounts of phosphine and required mol. sieves as dehydrating agent. Here, we address these limitations with an optimized method that requires only catalytic amounts of phosphine and no dehydrating agent. The new method utilizes a two-component organoreductant/organooxidant-recycling strategy to catalyze amide bond formation.

Journal of the American Chemical Society published new progress about 71989-31-6. 71989-31-6 belongs to catalysis-chemistry, auxiliary class Amino acide derivatives,pyrrolidine, name is Fmoc-Pro-OH, and the molecular formula is C20H19NO4, COA of Formula: C20H19NO4.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

de Souza, F. A. L. published the artcileNMR spectral parameters of open- and closed-shell graphene nanoflakes: Orbital and hyperfine contributions, Computed Properties of 191-07-1, the publication is Carbon (2022), 374-383, database is CAplus.

Graphene nanoflakes have attracted a growing interest owing to their tunable and unique electronic, optical, and magnetic properties. In particular, recent breakthroughs in the on-surface synthesis and characterization of graphene nanoflakes exhibiting ¦Ð-magnetism have shown their promising great potential for spintronic applications. In this context, a theor. investigation on the relative energetic stability, 13C NMR (NMR) chem. shifts, magnetically induced currents, hyperfine shifts, and hyperfine coupling constants of graphene nanoflakes of hexagonal and triangular shape has been performed using the d. functional theory (DFT). The role played by the size, shape, and at. site position in the flake on the 13C isotropic chem. shift is thoroughly examined As a general trend, considering only the orbital contribution, sites from the innermost region of the flake present lower chem. shifts than the ones close to the border and, for large enough systems, such values tend to converge to roughly the graphene one. For the open-shell flakes, the hyperfine shifts and coupling constants exhibit oscillatory behavior, with opposite signs for adjacent sites. The magnitude of these parameters is progressively reduced with the increase in the distance from the edge, where the largest values of excess spin d. are concentrated

Carbon published new progress about 191-07-1. 191-07-1 belongs to catalysis-chemistry, auxiliary class Electronic Materials, name is Coronene, and the molecular formula is C24H12, Computed Properties of 191-07-1.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Niedermoser, Sabrina published the artcileEvaluation of an automated double-synthesis module: efficiency and reliability of subsequent radiosyntheses of FHBG and FLT, Application In Synthesis of 17351-62-1, the publication is Nuclear Medicine and Biology (2012), 39(4), 586-592, database is CAplus and MEDLINE.

We optimized the synthesis methods for 3′-deoxy-3′-[¹⁸F]fluorothymidine ([¹⁸F]FLT) and 9-(4-[¹⁸F]fluoro-3-[hydroxymethyl]butyl)guanine) ([¹⁸F]FHBG) and automated them on an Explora General Nucleophilic double-synthesis module. Furthermore, the synthesis efficiency and reliability and the formation of cross-contaminations of the products when preparing two consecutive batches were evaluated. Whereas the preinstalled FLT synthesis conditions required substantial modification in reaction and neutralization conditions to achieve radiochem. yields of up to 60% within 70¡À10 min including high-performance liquid chromatog. purification, the synthesis of FHBG had to be implemented to the module to obtain competitive radiochem. yields of up to 40% in an overall synthesis time of 60¡À10 min. The radiochem. purities obtained were ¡Ý99% and ¡Ý96% for the synthesis of [¹⁸F]FLT and [¹⁸F]FHBG, resp. No significant changes in yield or purity could be observed between both batch productions. We found that the yields and purities also did not change when performing FLT after FHBG syntheses and vice versa. Hence, we developed a synthesis setup that offers the opportunity to perform two subsequent syntheses of either [¹⁸F]FLT, [¹⁸F]FHBG or [¹⁸F]FLT after [¹⁸F]FHBG without decrease in radiochem. yields and purities. Also, no cross-contaminations were observed, which can be attributed to the use of sep. product delivery tubes, purification columns and an automated intermediate cleaning program. These results open up the possibility of producing consecutively either two equal ¹⁸F-fluorinated tracers or two different ones in high yields on the same synthesis module.

Nuclear Medicine and Biology published new progress about 17351-62-1. 17351-62-1 belongs to catalysis-chemistry, auxiliary class Salt,Amine, name is Tetrabutylammonium hydrogencarbonate, and the molecular formula is C17H37NO3, Application In Synthesis of 17351-62-1.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Fuchte, Hanna E. published the artcileIdentification of sites with elevated PM levels along an urban cycle path using a mobile platform and the analysis of 48 particle bound PAH, Related Products of catalysis-chemistry, the publication is Atmospheric Environment (2022), 118912, database is CAplus.

Using a multidisciplinary approach, this study provides insight into everyday exposure scenarios of urban commuters to aerosol particles and their associated polycyclic aromatic hydrocarbons. It combines high spatiotemporal resolution particle measurements, used to determine the distribution of particulate matter in the urban environment, with the chem. anal. of the health-relevant particle fraction (< 2.5¦Ìm) at higher polluted sites. In Sept. 2019, multiple test rides were conducted using a mobile platform along an urban cycle path in Aachen, Germany. With this, particle number and mass concentrations were recorded. Based on this data, five sites with elevated levels of particulate matter concentrations were identified. At these locations, the airborne respirable particles (PM2.5) were collected using a high-volume sampler. These were then quantified for an extended set of PAH and alkylated PAH by GC-MS. The alkylated distribution pattern of PAH in the samples all exhibited a typical pyrogenic pattern. A more detailed assessment of toxicity was possible because PAH such as dibenzo[a,l]pyrene or 7H-benzo[c]fluorene could be taken into account. The non-EPA PAH contributed up to 81% to the total toxicity of the particles expressed in toxic equivalent The measurement of an extended set of PAH was beneficial and is highly recommended for future studies.

Atmospheric Environment published new progress about 191-07-1. 191-07-1 belongs to catalysis-chemistry, auxiliary class Electronic Materials, name is Coronene, and the molecular formula is C24H12, Related Products of catalysis-chemistry.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia