Month: December 2022

Schweighuber, Andrea published the artcileInvestigations on the influence of multiple extrusion on the degradation of polyolefins, Category: esters-buliding-blocks, the publication is Polymer Degradation and Stability (2021), 109689, database is CAplus.

The importance of mech. recycling of polymers has increased within the last decades, especially due to numerous regulations of governments all over the world. Hereby recycling quotas are enforced to pave the way towards a closed loop recycling. During its lifetime, polymers are exposed to multiple environmental factors, which can already induce degradation However, a major factor that needs to be taken into account is the increased thermo-mech. stress during the recycling process, which may have significant impact on the quality of recyclates as well. In the present work, polyolefins (high-d. polyethylene and polypropylene) were artificially exposed to stress by continuous extrusion at varying speeds and absence or presence of stabilizers to analyze the extent to which the recycling contributes to degradation processes. These samples were analyzed for low-mol.-weight stress markers by thermodesorption gas chromatog. and by high-performance liquid chromatog. (both coupled to mass spectrometric detection). Depending on the extent of stress, the occurrence of odd-numbered linear alkane chains was revealed in polyethylene samples, and of oxidized branched alkanes in polypropylene samples. Correlations with mol. weight (determined by high temperature gel permeation chromatog.) and with decreasing concentrations of stabilizers could be demonstrated.

Polymer Degradation and Stability published new progress about 31570-04-4. 31570-04-4 belongs to esters-buliding-blocks, auxiliary class Mono-phosphine Ligands, name is Tris(2,4-di-tert-butylphenyl) phosphite, and the molecular formula is C12H13NO3, Category: esters-buliding-blocks.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Joshi, Sumedh published the artcileAntibacterial Strategy against H. pylori: Inhibition of the Radical SAM Enzyme MqnE in Menaquinone Biosynthesis, Category: esters-buliding-blocks, the publication is ACS Medicinal Chemistry Letters (2019), 10(3), 363-366, database is CAplus and MEDLINE.

Aminofutalosine synthase (MqnE) catalyzes an important rearrangement reaction in menaquinone biosynthesis by the futalosine pathway. We report the identification of previously unreported inhibitors of MqnE using a mechanism-guided approach. The best inhibitor shows efficient inhibitory activity against Helicobacter pylori (IC₅₀ = 1.8 ± 0.4 μM) and identifies MqnE as a promising target for antibiotic development.

ACS Medicinal Chemistry Letters published new progress about 1877-71-0. 1877-71-0 belongs to esters-buliding-blocks, auxiliary class Carboxylic acid,Benzene,Ester, name is 3-(Methoxycarbonyl)benzoic acid, and the molecular formula is C9H8O4, Category: esters-buliding-blocks.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Joshi, Sumedh published the artcileMenaquinone Biosynthesis: New Strategies to Trap Radical Intermediates in the MqnE-Catalyzed Reaction, HPLC of Formula: 1877-71-0, the publication is Biochemistry (2021), 60(21), 1642-1646, database is CAplus and MEDLINE.

Aminofutalosine synthase (MqnE) is a radical SAM enzyme that catalyzes the conversion of 3-((1-carboxyvinyl)oxy)benzoic acid to aminofutalosine during the futalosine-dependent menaquinone biosynthesis. In this Communication, the authors report the trapping of a radical intermediate in the MqnE-catalyzed reaction using sodium dithionite, mol. oxygen, or 5,5-dimethyl-1-pyrroline-N-oxide. These radical trapping strategies are potentially of general utility in the study of other radical SAM enzymes.

Biochemistry published new progress about 1877-71-0. 1877-71-0 belongs to esters-buliding-blocks, auxiliary class Carboxylic acid,Benzene,Ester, name is 3-(Methoxycarbonyl)benzoic acid, and the molecular formula is C9H8O4, HPLC of Formula: 1877-71-0.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Brokl, Michal published the artcileImprovement of ylang-ylang essential oil characterization by GC × GC-TOFMS, Product Details of C12H14O2, the publication is Molecules (2013), 1783-1797, database is CAplus and MEDLINE.

A single fraction of essential oil can often contain hundreds of compounds Despite of the tech. improvements and the enhanced selectivity currently offered by the state-of-the-art gas chromatog. (GC) and mass spectrometry (MS) instruments, the complexity of essential oils is frequently underestimated. Comprehensive two-dimensional GC coupled to time-of-flight MS (GC × GC-TOFMS) was used to improve the chem. characterization of ylang-ylang essential oil fractions recently reported in a previous one-dimensional (1D) GC study. Based on both, the enhanced chromatog. separation and the mass spectral deconvolution, 161 individual compounds were identified and labeled as potentially characteristic analytes found in both low and high boiling fractions issued from distillation of mature ylang-ylang flowers. Compared to the most recent full GC-MS characterization, this represents 75 new compounds, essentially consisting of terpenes, terpenoid esters, and alcs.

Molecules published new progress about 5205-11-8. 5205-11-8 belongs to esters-buliding-blocks, auxiliary class Alkenyl,Benzene,Ester, name is 3-Methylbut-2-en-1-yl benzoate, and the molecular formula is C12H14O2, Product Details of C12H14O2.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Day, Daniel M. published the artcileAn experimental investigation into the kinetics and mechanism of the aza-Michael additions of dimethyl itaconate, Recommanded Product: Dimethyl itaconate, the publication is Tetrahedron (2022), 132921, database is CAplus.

The aza-Michael addition is a versatile reaction for the modification of α,β-unsaturated carbonyl compounds with amines. The reactivity of di-Me itaconate as a bio-based Michael acceptor is explored in this work. Through its reactions with piperidine and dibutylamine, it was found that the order of reaction can be changed by the choice of catalyst, solvent, or the concentration of the amine reactant. The effectiveness of catalysts was proportional to their Lewis acidity. Competitive isomerisation of di-Me itaconate into unreactive regioisomers can be suppressed using low-polarity solvents and lower temperatures This investigation of the aza-Michael additions of di-Me itaconate has clarified the possible reaction mechanisms and optimized the protocol, supporting further use of this reaction in small mol. synthesis and modification of polymers.

Tetrahedron published new progress about 617-52-7. 617-52-7 belongs to esters-buliding-blocks, auxiliary class Alkenyl,Aliphatic hydrocarbon chain,Ester, name is Dimethyl itaconate, and the molecular formula is C7H10O4, Recommanded Product: Dimethyl itaconate.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Saxena, Mohit published the artcileA cytotoxic and hepatoprotective agent from Withania somnifera and biological evaluation of its ester derivatives, Application In Synthesis of 110-34-9, the publication is Natural Product Communications (2007), 2(7), 775-778, database is CAplus.

Detailed chem. investigation of Withania somnifera roots resulted in the isolation and identification of a cytotoxic and hepatoprotective agent, palmitic acid (1), which was converted to 8 semi-synthetic ester derivatives 2-9. T-Bu palmitate (8) and amyl palmitate (9) were 4-6 times more active than 1 against adherent and suspension colon cancer cell lines. Interestingly, palmitic acid (1) and its ester derivatives 2-9 also showed hepatoprotective activity which is being reported for the 1st time.

Natural Product Communications published new progress about 110-34-9. 110-34-9 belongs to esters-buliding-blocks, auxiliary class Aliphatic hydrocarbon chain,Ester, name is Isobutyl palmitate, and the molecular formula is C20H40O2, Application In Synthesis of 110-34-9.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Page, Philip C. Bulman published the artcileNew Chiral Binaphthalene-Derived Iminium Salt Organocatalysts for Asymmetric Epoxidation of Alkenes, Quality Control of 126613-06-7, the publication is Journal of Organic Chemistry (2007), 72(12), 4424-4430, database is CAplus and MEDLINE.

A series of binaphthalene-fused azepinium salts I (R = Me₂CH, Me₃C, n-Bu, cyclohexyl, 2,6-Me₂C₆H₃) has been prepared and used as organocatalysts in the asym. epoxidation of unfunctionalized alkenes, giving rise to ees of up to 84%.

Journal of Organic Chemistry published new progress about 126613-06-7. 126613-06-7 belongs to esters-buliding-blocks, auxiliary class Chiral Diphenols, name is (R)-[1,1′-Binaphthalene]-2,2′-diyl bis(trifluoromethanesulfonate), and the molecular formula is C22H12F6O6S2, Quality Control of 126613-06-7.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Wei, Zhengxi published the artcileA direct peptide reactivity assay using a high-throughput mass spectrometry screening platform for detection of skin sensitizers, Synthetic Route of 121-79-9, the publication is Toxicology Letters (2021), 67-77, database is CAplus and MEDLINE.

Chem.-peptide conjugation is the mol. initiating event in skin sensitization. The OECD test guideline uses a high-performance liquid chromatog./UV (HPLC/UV) detection method to quantify chem.-peptide conjugation in a direct peptide reactivity assay (DPRA), which measures the depletion of two synthetic peptides containing lysine or cysteine residues. To improve assay throughput, sensitivity and accuracy, an automated 384-well plate-based RapidFire solid-phase extraction (SPE) system coupled with tandem mass spectrometry (MS/MS) DPRA was developed and validated in the presence of a newly designed internal standard Compared to the HPLC/UV-based DPRA, the automated SPE-MS/MS-based DPRA improved throughput from 16 min to 10 s per sample, and substrate peptides usage was reduced from 100 mM to 5μM. When implementing the SPE-MS/MS-based DPRA into a high-throughput platform, we found 10 compounds that depleted lysine peptide and 24 compounds that depleted cysteine peptide (including 7 unreported chems. from 55 compounds we tested) in a concentration-response manner. The adduct formation between cysteine and cinnamic aldehyde and ethylene glycol dimethacrylate were further analyzed using high-performance liquid chromatog. time-of-flight mass spectrometry (HPLC-TOF-MS) to confirm the conjugation. Overall, the automated SPE-MS/MS-based platform is an efficient, economic, and accurate way to detect skin sensitizers.

Toxicology Letters published new progress about 121-79-9. 121-79-9 belongs to esters-buliding-blocks, auxiliary class Natural product, name is Propyl 3,4,5-trihydroxybenzoate, and the molecular formula is C7H5Cl2NO2, Synthetic Route of 121-79-9.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Wang, Yi published the artcileDiscovery of SARS-CoV-2-E channel inhibitors as antiviral candidates, Product Details of C6H8O4, the publication is Acta Pharmacologica Sinica (2022), 43(4), 781-787, database is CAplus and MEDLINE.

Abstract: Lack of efficiency has been a major problem shared by all currently developed anti-SARS-CoV-2 therapies. Our previous study shows that SARS-CoV-2 structural envelope (2-E) protein forms a type of cation channel, and heterogeneously expression of 2-E channels causes host cell death. In this study we developed a cell-based high throughput screening (HTS) assay and used it to discover inhibitors against 2-E channels. Among 4376 compounds tested, 34 hits with cell protection activity were found. Followed by an anti-viral anal., 15 compounds which could inhibit SARS-CoV-2 replication were identified. In electrophysiol. experiments, three representatives showing inhibitory effect on 2-E channels were chosen for further characterization. Among them, proanthocyanidins directly bound to 2-E channel with binding affinity (K_D) of 22.14 μM in surface plasmon resonance assay. Mol. modeling and docking anal. revealed that proanthocyanidins inserted into the pore of 2-E N-terminal vestibule acting as a channel blocker. Consistently, mutations of Glu 8 and Asn 15, two residues lining the proposed binding pocket, abolished the inhibitory effects of proanthocyanidins. The natural product proanthocyanidins are widely used as cosmetic, suggesting a potential of proanthocyanidins as disinfectant for external use. This study further demonstrates that 2-E channel is an effective antiviral drug target and provides a potential antiviral candidate against SARS-CoV-2.

Acta Pharmacologica Sinica published new progress about 624-49-7. 624-49-7 belongs to esters-buliding-blocks, auxiliary class Inhibitor,Natural product, name is Dimethyl fumarate, and the molecular formula is C7H7IN2O, Product Details of C6H8O4.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Wang, Yun-Peng published the artcileAn efficient approach to angular tricyclic molecular architecture via Nazarov-like cyclization and double ring-expansion cascade, HPLC of Formula: 30414-53-0, the publication is Nature Communications (2022), 13(1), 2335, database is CAplus and MEDLINE.

A modular and efficient method for constructing angular tri-carbocyclic architectures containing quaternary carbon center(s), e.g., I (R = Me) from 1,3-dicycloalkylidenyl ketones, e.g., II is established, which involves an unconventional synergistic cascade of a Nazarov cyclization and two ring expansions. It features high selectivity, mild conditions and convenient operation, wide scope and easy availability of substrate. Substitution at the 4πe-system with electron-donating group favors this reaction, while that with electron-withdrawing group or proton disfavors. The electron-donating group directs the initial ring expansion at its own site, while the p-π- or n-π- associated substituent favors selectively the later ring expansion near its location because of the beneficial maintenance of an original conjugated system. The stereoselectivity has proved to be governed by either the steric effect at the expanded rings, or the migration ability of the migrating atom. D. Functional Theory calculation suggests that the initial Nazarov cyclization would be the rate-determining step. A racemic total synthesis of the natural (±)-waihoensene is realized in 18 steps by use of this methodol.

Nature Communications published new progress about 30414-53-0. 30414-53-0 belongs to esters-buliding-blocks, auxiliary class Aliphatic hydrocarbon chain,Ketone,Ester, name is Methyl 3-oxovalerate, and the molecular formula is C15H14O, HPLC of Formula: 30414-53-0.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics