Month: December 2022

Oliveira, Michelle Leal published the artcileLong-term bond strength of glass fiber post to composite resin does not depend on surface treatment with silane coupling agent or universal adhesive, Related Products of esters-buliding-blocks, the publication is International Journal of Adhesion and Adhesives (2021), 102931, database is CAplus.

This study evaluated the effect of glass fiber post (GFP) surface treatment with or without a silane coupling agent, associated with adhesive systems with or without silane in their composition, on the long-term bond strength to resin composite. Sixty GFPs (Whitepost DC number 2, FGM) were cleaned using 70% ethanol, and randomly divided into two groups, either with or without pretreatment with silane (Ceramic Primer, 3 M ESPE), for 60 s. Each group was further subdivided into three groups, according to the adhesive system applied over the GFP (n = 10): UAS (Scotchbond Universal, 3 M ESPE), E&R – etch-and-rinse adhesive system (Adper Single Bond Plus, 3 M ESPE), and a control group with no adhesive system. The GFPs were centralized in a cylindrical matrix, and a nanoparticulate resin composite (Filtek Supreme Ultra, 3 M ESPE) was inserted and photoactivated. After 48 h, the samples were sectioned in slices, two of which were immediately (48 h) submitted to the push-out bond strength test, and another two, after 6 mo of storage in water. The failure mode was evaluated with a stereomicroscope under 40x magnification, and classified using scores. Three-way ANOVA (α = 0.05) showed that the triple interaction of pretreatment with silane, use of adhesive and time period were significant (p = 0.019). After 48 h, the application of silane resulted in a significant increase in bond strength values, regardless of the adhesive application (p = 0.013), but this effect was no longer observed after 6 mo (p = 0.677). Application of UAS did not influence bond strength values, regardless of silane application or storage time (p > 0.05). As for E&R, significantly higher bond strength was observed after 6 mo, compared with 48 h (p = 0.040). When post silanization was performed with no adhesive system, there was no difference in bond strength between 48 h and 6 mo storage time (p > 0.05). When there was neither silanization, nor an adhesive system, a significantly higher bond strength was observed after 6 mo, compared with 48 h (p < 0.05). Most of the failure types were classified as mixed in both of the water storage time periods. The long-term bond strength of the GFP to composite resin did not depend on post surface treatment with silane, or application of either a UAS or a E&R system.

International Journal of Adhesion and Adhesives published new progress about 10287-53-3. 10287-53-3 belongs to esters-buliding-blocks, auxiliary class Amine,Benzene,Ester, name is Ethyl 4-dimethylaminobenzoate, and the molecular formula is C11H15NO2, Related Products of esters-buliding-blocks.

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

Teyssandier, Joan published the artcilePolydiacetylene photocomposite material obtained by orthogonal chemistry: a detailed study at the mesoscopic scale, Formula: C15H20O6, the publication is Materials Advances (2022), 3(5), 2558-2567, database is CAplus.

A recent paper reported the spatially controlled photopolymerization and subsequent 3D printing of polydiacetylene (PDA) by orthogonal chem. using dual-wavelength polymerization Diacetylene monomers were dispersed in an acrylate resin to form a photocomposite in a two-step process: a first irradiation photopolymerizes the acrylate freezing the diacetylene monomers which were polymerized in a second step at a different wavelength. In the present article, for a better understanding of the organization of the generated functional composites, this process is studied at the mesoscopic scale by performing optical and SEM combined with correlative Raman, AFM and cathodoluminescence measurements. We have diluted the PCDA/acrylate blend in dichloromethane (CH₂Cl₂) and performed drop casting deposition on graphite. We discovered that the acrylate-diacetylene mixture promotes dramatically the formation of large PDA crystals. The confinement of PDA crystals inside the polyacrylate hindered their thermochromic blue-to-red transition, as revealed by correlative Raman microscopy. Cathodoluminescence measurements on the photocomposite have also shown that the light emission properties of PDAs are strongly modified by the induced confinement.

Materials Advances published new progress about 15625-89-5. 15625-89-5 belongs to esters-buliding-blocks, auxiliary class Polymerization Reagents,Crosslinkers, name is Trimethylolpropane triacrylate, and the molecular formula is C5H11NO2S, Formula: C15H20O6.

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

Liu, Hengrui published the artcileCharacterization of a patient-derived variant of GPX4 for precision therapy, Product Details of C6H8O4, the publication is Nature Chemical Biology (2022), 18(1), 91-100, database is CAplus and MEDLINE.

Glutathione peroxidase 4 (GPX4), as the only enzyme in mammals capable of reducing esterified phospholipid hydroperoxides within a cellular context, protects cells from ferroptosis. We identified a homozygous point mutation in the GPX4 gene, resulting in an R152H coding mutation, in three patients with Sedaghatian-type spondylometaphyseal dysplasia. Using structure-based analyses and cell models, including patient fibroblasts, of this variant, we found that the missense variant destabilized a critical loop, which disrupted the active site and caused a substantial loss of enzymic function. We also found that the R152H variant of GPX4 is less susceptible to degradation, revealing the degradation mechanism of the GPX4 protein. Proof-of-concept therapeutic treatments, which overcome the impaired R152H GPX4 activity, including selenium supplementation, selective antioxidants and a deuterated polyunsaturated fatty acid were identified. In addition to revealing a general approach to investigating rare genetic diseases, we demonstrate the biochem. foundations of therapeutic strategies targeting GPX4.

Nature Chemical Biology 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 C6H8O4, Product Details of C6H8O4.

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

Adam, Jean-Michel published the artcileDevelopment of a Scalable Synthesis of (S)-3-Fluoromethyl-γ-butyrolactone, Building Block for Carmegliptin’s Lactam Moiety, Quality Control of 115314-17-5, the publication is Organic Process Research & Development (2011), 15(3), 515-526, database is CAplus.

Several new routes are reported for the synthesis of (S)-3-fluoromethyl-γ-butyrolactone. An asym. hydrogenation-based synthesis was chosen as the enabling route to produce the lactone on a 10-kg scale. A superior stereoselective route starting from (S)-tert-Bu glycidyl ether which afforded the desired lactone in three steps with ∼50% overall yield was finally selected for further development and production

Organic Process Research & Development published new progress about 115314-17-5. 115314-17-5 belongs to esters-buliding-blocks, auxiliary class Epoxides,Chiral,Nitro Compound,Sulfonate,Benzene, name is (R)-Oxiran-2-ylmethyl 3-nitrobenzenesulfonate, and the molecular formula is C9H9NO6S, Quality Control of 115314-17-5.

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

Rayne, Sierra published the artcilepH dependent partitioning behaviour of food and beverage aroma compounds between air-aqueous and organic-aqueous matrices, Recommanded Product: Ethyl 2-mercaptopropanoate, the publication is Flavour and Fragrance Journal (2016), 31(3), 228-234, database is CAplus.

Aroma compounds in the Flavornet database were screened for ionizable functional groups such as carboxylic acids, aliphatic and aromatic amines, phenols, alcs. and thiols. Of the 738 aroma compounds listed in this database, 101 mols. have ionizable moieties with estimated monomeric aqueous pK_a values ranging between 1.75 and 10.97. pH dependent effective air/water partitioning coefficients (K_aw,eff) and n-octanol/water partitioning coefficients (D_ow) were estimated for all ionizable aroma compounds over the pH range from 0 to 14. The ionizable aroma compounds display a broad range of K_aw,eff (1.8 × 10^-23 to 6.1 atm M^-1) and log D_ow (-6.2 to +7.2 units) values. For many aroma compounds, pH dependent ionization will have a significant effect on K_aw,eff and D_ow, leading to variations in these physico-chem. properties by up to 11 orders of magnitude over the composite pH range of common foods and beverages. Changes in food and beverage pH affect not only the relative contributions of neutral vs. charged forms of ionizable aroma compounds (which directly affects analyte volatility and olfactory reception), but also partitioning between freely dissolved and sorbed forms of the analyte in solution (which indirectly affects analyte volatility). Copyright © 2015 John Wiley & Sons, Ltd.

Flavour and Fragrance Journal published new progress about 19788-49-9. 19788-49-9 belongs to esters-buliding-blocks, auxiliary class Thiol,Aliphatic hydrocarbon chain,Ester, name is Ethyl 2-mercaptopropanoate, and the molecular formula is C5H10O2S, Recommanded Product: Ethyl 2-mercaptopropanoate.

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

Rayne, Sierra published the artcileCarboxylic acid ester hydrolysis rate constants for food and beverage aroma compounds, Synthetic Route of 19788-49-9, the publication is Flavour and Fragrance Journal (2016), 31(5), 385-394, database is CAplus.

Aroma compounds in the Flavornet database were screened for potentially hydrolysable carboxylic acid ester functionalities. Of 738 aroma compounds listed in this database, 140 mols. contain carboxylic acid ester groups that may be amenable to hydrolysis in various food and beverage products. Acid- (k_A) and base- (k_B) catalyzed and neutral (k_N) hydrolysis rate constants in pure water at 25°C were calculated for these aroma compounds Where available, good agreement between theor. and exptl. hydrolytic half-lives was obtained at various pH values. Wide ranges and broad frequency distributions for k_A, k_B, and k_N are expected among the various hydrolyzable aroma compounds, with calculated k_A ranging from 3.7 × 10^-8 to 4.7 × 10^-4 M^-1 s^-1, calculated k_B ranging from 4.3 × 10^-4 to 43 M^-1 s^-1, and calculated k_N ranging from 4.2 × 10^-17 to 7.6 × 10^-9 M^-1 s^-1. The resulting hydrolytic half-lives also range widely, from 10 days to 370 years at pH 2.8, 18 days to 4,900 years at pH 4.0, 1.8 days to 470 years at pH 7.0, and 26 min to 5.1 years at pH 9.0. The findings illustrate the importance of considering abiotic hydrolysis and matrix pH when modeling the evolution of sensory characteristics for foods and beverages with carboxylic acid ester based aroma compounds Copyright © 2016 John Wiley & Sons, Ltd.

Flavour and Fragrance Journal published new progress about 19788-49-9. 19788-49-9 belongs to esters-buliding-blocks, auxiliary class Thiol,Aliphatic hydrocarbon chain,Ester, name is Ethyl 2-mercaptopropanoate, and the molecular formula is C5H10O2S, Synthetic Route of 19788-49-9.

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

Portaccio, Emilio published the artcileImpact of COVID-19 on multiple sclerosis care and management: Results from the European Committee for Treatment and Research in Multiple Sclerosis survey, Safety of Dimethyl fumarate, the publication is Multiple Sclerosis Journal (2022), 28(1), 132-138, database is CAplus and MEDLINE.

Background:: The spread of Coronavirus disease-19 (COVID-19) poses unique challenges in the management of people with multiple sclerosis (PwMS). Objectives:: To collect data about the impact of COVID-19 emergency on access to care for PwMS and on MS treatment practices. Methods:: Between March and July 2020, the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) promoted an online survey covering patient access to care, management of relapses and visits, disease-modifying therapy (DMT) and experience with COVID-19. Results:: Three-hundred and sixty neurologists from 52 countries (68from Europe) completed the survey. 98reported COVID-19-related restrictions. Telemedicine was adopted to overcome the limited access to care and was newly activated (73) or widely implemented (17). 70reported changes in DMT management. Interferons and glatiramer were considered safe. No modifications were considered for natalizumab in 64, cladribine in 24, anti-CD20 in 22and alemtuzumab in 17; 18(for alemtuzumab and cladribine) and 43(for anti-CD20) considered postponing treatment. Conclusion:: The ECTRIMS survey highlighted the challenges in keeping standards of care in clin. practice. Telemedicine clearly needs to be implemented. Gathering data on DMT safety will remain crucial to inform treatment decisions.

Multiple Sclerosis Journal 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 C6H8O4, Safety of Dimethyl fumarate.

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

Andreev, V. M. published the artcileThe synthesis of esters of 2-methyl-2-buten-4-ol (prenol) and 2-methyl-1-buten-4-ol (isobutenyl carbinol), Recommanded Product: 3-Methylbut-2-en-1-yl benzoate, the publication is Pishchevaya Promyshlennost (Moscow, Russian Federation) (1992), 22, database is CAplus.

Perfumes RCO₂R’ (RCO₂ = benzoate, cinnamate, salicylate, isobutyrate, phenylacetate, phenoxyacetate, nicotinate; R’ = prenyl, isobutenylcarbinyl) were prepared in ≤79% yield in the K₂CO₃-catalyzed transesterification of RCO₂Me with R’OH. The odors were evaluated.

Pishchevaya Promyshlennost (Moscow, Russian Federation) 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, Recommanded Product: 3-Methylbut-2-en-1-yl benzoate.

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

Moore, Gordon G. published the artcilePreparation of hindered esters by the alkylation of carboxylate salts with simple alkyl halides, Category: esters-buliding-blocks, the publication is Journal of Organic Chemistry (1979), 44(14), 2425-9, database is CAplus.

Sterically hindered esters were prepared in excellent yields by the use of anion-exchange resins in both biphase and triphase systems. In addition, quant. yields of a variety of esters were obtained by the displacement reactions of simple aliphatic and aromatic K carboxylate salts and alkyl halides in Me₂CO or aqueous Me₂CO. Esters prepared in quant. yields included Et hexadecanoate in 95% Me₂CO and Et 2,4,6-trimethylbenzoate, 1-methylheptyl 2,4,6-trimethylbenzoate, and Et 9,10-epoxyoctadecanoate in pure Me₂CO. The 2nd-order rate constant for the reaction of K 2,4,6-trimethylbenzoate with iodoethane in 95% acetone was 2.67 × 10^-4 mL^-1s^-1 at 40°.

Journal of Organic Chemistry published new progress about 5340-78-3. 5340-78-3 belongs to esters-buliding-blocks, auxiliary class Aliphatic Chain, name is Ethyltert-butylacetate, and the molecular formula is C8H16O2, Category: esters-buliding-blocks.

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

Maniar, Dina published the artcileEnzymatic Synthesis of Muconic Acid-Based Polymers: Trans, Trans-Dimethyl Muconate and Trans, β-Dimethyl Hydromuconate, Computed Properties of 627-93-0, the publication is Polymers (Basel, Switzerland) (2021), 13(15), 2498, database is CAplus and MEDLINE.

The vast majority of commodity polymers are acquired from petrochem. feedstock, and these resources will plausibly be depleted within the next 100 years. Therefore, the utilization of carbon-neutral renewable resources for the production of polymers is crucial in modern green chem. Herein, we report an eco-friendly strategy that uses enzyme catalysis to design biobased unsaturated (co)polyesters from muconic acid derivatives This method is an attractive pathway for the production of well-defined unsaturated polyesters with min. side reactions. A suite of characterization techniques was performed to probe the reaction mechanism and properties of the obtained polyesters. It is rationalized that the alkene functionality of the muconate monomers plays an important role in the enzyme catalysis mechanism. The rendered polyesters possessed excellent thermal stabilities and unreacted alkene functionality that can consecutively undergo chain extension, copolymerization, or act as an anchor for other functional groups. These properties open new avenues in the fields of unsaturated polyester resins and photosensitive coatings.

Polymers (Basel, Switzerland) published new progress about 627-93-0. 627-93-0 belongs to esters-buliding-blocks, auxiliary class Ploymers, name is Dimethyl adipate, and the molecular formula is C8H14O4, Computed Properties of 627-93-0.

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