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Triptolide, a bioactive diterpene tri-epoxide extracted from Tripterygium wilfordii Hook F (TWHF), exhibits notable pharmacological activities, including anti-inflammatory, immunosuppressive, antifertility, and anticancer effects. Despite its promising therapeutic potential, clinical applications of triptolide are significantly limited by its poor water solubility and substantial toxicity, particularly hepatotoxicity, nephrotoxicity, and cardiotoxicity. These toxic effects are difficult to separate from many of its desired therapeutic effects, the Yin and Yang of triptolide applications. Triptolides therapeutic and toxic effects are linked to its inhibitory interactions with XPB, a DNA helicase essential for transcription by RNA polymerase II (RNAPII) and nucleotide excision repair (NER). By irreversibly binding to XPB, triptolide inhibits its ATPase activity, leading to global repression of transcription and impaired NER, which underlies its cytotoxic and antitumor properties. Recent developments, including triptolide prodrugs such as Minnelide and derivatives like glutriptolides, aim to enhance its pharmacokinetic properties and reduce toxicity. This review critically examines triptolides chemical structure, therapeutic applications, toxicological profile, and molecular interactions with XPB and other protein targets to inform future strategies that maximize therapeutic efficacy while minimizing adverse effects.

Drugs that inhibit HIV transcription and/or reactivation of latent HIV have been proposed as a strategy to reduce HIV-associated immune activation or to achieve a functional cure, yet comparative studies are lacking. We evaluated 26 drugs, including drugs previously reported to inhibit HIV transcription (inhibitors of Tat-dependent HIV transcription, Rev, HSF-1/PTEF-b, HSP90, Jak/Stat, or SIRT1/Tat deacetylation) and other agents that were not tested before (inhibitors of PKC, NF-κB, SP-1, or histone acetyltransferase; NR2F1 agonists), elongation (inhibitors of CDK9/ PTEF-b), completion (inhibitors of PolyA-polymerase), or splicing (inhibitors of human splice factors). To investigate if those drugs would vary in their ability to affect different blocks to HIV transcription, we measured levels of initiated, elongated, midtranscribed, completed, and multiply spliced HIV RNA in PBMCs from antiretroviral therapy-suppressed individuals following ex vivo treatment with each drug and subsequent T cell activation. We identified new drugs that prevent HIV reactivation, including CDK and splicing inhibitors. While some drugs inhibited 1 or 2 steps, other drugs (CDK inhibitors, splicing inhibitors, tanespimycin, and triptolide) inhibited multiple stages of HIV transcription and blocked the production of supernatant viral RNA. These drugs and targets deserve further study in strategies aimed at reducing HIV-associated immune activation or achieving a functional cure.

Allogeneic hematopoietic stem cell transplantation (aHSCT) can cure patients with otherwise fatal leukemias and lymphomas. However, the benefits of aHSCT are limited by graft-versus-host disease (GVHD). Minnelide, a water-soluble analog of triptolide, has demonstrated potent antiinflammatory and antitumor activity in several preclinical models and has proven both safe and efficacious in clinical trials for advanced gastrointestinal malignancies. Here, we tested the effectiveness of Minnelide in preventing acute GVHD as compared with posttransplant cyclophosphamide (PTCy). Strikingly, we found Minnelide improved survival, weight loss, and clinical scores in an MHC-mismatched model of aHSCT. These benefits were also apparent in minor MHC-matched aHSCT and xenogeneic HSCT models. Minnelide was comparable to PTCy in terms of survival, GVHD clinical score, and colonic length. Notably, in addition to decreased donor T cell infiltration early after aHSCT, several regulatory cell populations, including Tregs, ILC2s, and myeloid-derived stem cells in the colon were increased, which together may account for Minnelides GVHD suppression after aHSCT. Importantly, Minnelides GVHD prevention was accompanied by preservation of graft-versus-tumor activity. As Minnelide possesses anti-acute myeloid leukemia (anti-AML) activity and is being applied in clinical trials, together with the present findings, we conclude that this compound might provide a new approach for patients with AML undergoing aHSCT.

Propylene liquid-phase epoxidation with 50–75% H 2 O 2 is an important process for the industrial production of propylene oxide (PO). To realize a propylene epoxidation process that proceeds with low hydrogen peroxide concentration, we developed an integrated Mn/TS-1/N catalytic system via in-situ reaction of Mn/TS-1 with an N-donor ligand, affording the PO product in excellent yield with only 30 wt% H 2 O 2. Other long-chain aliphatic epoxides were also readily synthesized by this catalytic epoxidation system. Moreover, in addition to the standard micro-pressure reactor, a continuous-flow microreactor was developed that executed the hydrogen peroxide propylene oxide (HPPO) process with excellent efficiency for 1300 hours. This innovative Mn/TS-1/N catalyzed epoxidation represents a promising direction for advancing HPPO industrial processes, offering improved efficiency while minimizing the reliance on high concentrations of H 2 O 2. [ABSTRACT FROM AUTHOR]

α-Amino ketones were synthesized by a Meinwald rearrangement of biomass-based amino epoxides using copper(II) triflate as a catalyst. The regioselectivity of the rearrangement can be rationalized in terms of the reaction proceeding via the most stable carbocationic intermediate to give various α-amino α′-aryl ketones in moderate to good yields. This is an attractive method to prepare α-amino ketones using a benign and inexpensive catalyst. [ABSTRACT FROM AUTHOR]

This paper describes a ferric nitrene/photoredox dual-catalyzed anti-Markovnikov ring-opening of epoxides under neutral conditions for providing α-substituted acetophenones. A DFT-based calculation supported the reaction regioselectivity. The catalytic system could also be applied to the formation of C–O and C–N bonds via nucleophilic functionalization of benzylic C–H bonds. [ABSTRACT FROM AUTHOR]

Development of the high-power devices based on the third-generation semiconductor puts forward a high requirement for the thermal performance of electronic packaging materials. In this study, we employed oligomeric bismaleimide (BMI), multifunctional epoxy resin (EP), and 4.4'-daminodiphenylmethane (DDM) as the resin matrix to prepare a new BMI/EP/DDM (BED) ternary resin molding compound aiming for high-temperature electronic packaging. With 2-ethyl-4-methylimidazole as the curing accelerator, the reactions including the addition of BMI with DDM, addition of EP with DDM, self-polymerization of EP, and self-polymerization of BMI facilely occurred during the curing process of BED system, making the molding process of BED be compatible with that of commercial epoxy molding compounds (EMC). With increasing the BMI content, the thermal stability of the cured BED resins was improved, showing the initial thermal decomposition temperature and char yield at 800 °C up to 388 °C and 55.7%, respectively. Compared with EMC, the BED molding compounds exhibited a glass transition temperature over 360 °C and a remarkable dimensional stability in the glassy state after curing, due to the enhancement of network chain rigidity by the introduction of BMI component. Although the cured BED was less ductile than the cured EMC at room temperature, showing lower flexural strength and higher flexural modulus, it had much superior flexural performance to the cured EMC at 250 °C. Therefore, BED was demonstrated to be a promising candidate for high-temperature electronic packaging applications. [ABSTRACT FROM AUTHOR]

Herein, we report the first synthesis of poly(ester-block-vinyl acetate) via epoxide/anhydride ring-opening copolymerisation and reversible addition–fragmentation chain transfer polymerisation. This was achieved using simple, robust and bifunctional alkali metal carboxylates featuring a xanthate unit. [ABSTRACT FROM AUTHOR]

Chip packaging engineering has evolved significantly to meet the performance demands of integrated circuits (IC) and micro-electromechanical systems (MEMS). Layers, mainly composed of metals, ceramics, and polymers are utilized to safeguard circuits and facilitate electrical connections. While, mechanical testing ensures bonding properties and reliability of bi-material interfaces in these components, there is a lack of discussion on the advantages and disadvantages of different test methods. Environmental factors, notably humidity and temperature, pose significant challenges, with a gap in understanding each condition's impact on interfaces. This review aims to provide comprehensive insights into the mechanical characterization of bi-material interfaces and their response to environmental conditions. It's divided into two main parts: a review of mechanical approaches in characterizing bi-material interfaces, including strength and quasi-static fracture tests and the presentation of test results considering temperature and humidity influence. The paper highlights the effects of humidity and high temperatures on the interface fracture energy, primarily due to the properties of polymeric materials in packaging for different interfaces. Additionally, it offers a summarized approach for selecting testing setups based on the desired interface. [ABSTRACT FROM AUTHOR]

The conversion of CO2 into valuable chemicals is a crucial field of research. Cyclic organic carbonates have attracted great interest because they can be prepared under mild conditions and because of their structural versatility which enables a large variety of applications. Therefore, there is a need for potent and yet practical catalysts for the cycloaddition of CO2 to cyclic carbonates that are able to combine availability, low cost and an adequate performance. We review here several recyclable catalytic systems that are readily available, easy to prepare, and inexpensive with an eye to the future development of more efficient practical catalysts through the provided guidelines. [ABSTRACT FROM AUTHOR]

Two new cobalt/zinc-coordinated bifunctional covalent organic polymers (COP-Co and COP-Zn) based on chlorhexidine are prepared as heterogeneous catalysts for carbon dioxide (CO2) conversion. Due to the Cl− nucleophile and cobalt/zinc Lewis acid sites, COP-Co and COP-Zn can efficiently convert CO2 and epoxides into cyclic carbonates under mild conditions without a co-catalyst. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) serves as a cheap, abundant, and renewable C1 building block for the synthesis of organic compounds and polymers. Selective and efficient CO2 fixation processes are still challenging because of the kinetic and thermodynamic stability of CO2. Among various CO2 fixation processes, the ring-opening copolymerization (ROCOP) of epoxides and CO2 gives aliphatic polycarbonates with high atom economy, although the chemical and physical properties of the resulting polycarbonates are not necessarily satisfactory. Introducing the third monomers into this ROCOP system provides new terpolymers, and the thermal, optical, mechanical or degradation properties can be added or tuned by incorporating new polymer backbones derived from the third monomers at the expense of the CO2 content. Here we review the terpolymerization reactions of epoxides, CO2, and the third monomers such as cyclic anhydrides, lactones, lactides, heteroallenes, and olefins. The development of catalysts and the control of the polymer structures are described together with the chemical and physical properties of the resulting polymers. [ABSTRACT FROM AUTHOR]

New reaction systems "oxirane – nucleophile X– – proton‐donor reagent AH – solvent" have been proposed for the detection of epoxides in which nucleophilic opening of the oxirane ring occurs accompanied by the formation of a colored product. The kinetic and mechanistic regularities of reactions in the proposed systems were investigated. Reaction orders with respect to the components of the systems have been determined: close to 1 – for oxirane and X−, close to 0 – for AH. It was shown that the proposed chromogenic reactions represent nucleophilic substitution of SN2‐type and allow the detection of epoxides containing both a terminal and internal epoxy group, which can be used to monitor processes in systems where epoxides are either the initial compounds or the synthesis products. Based on the conducted studies, it is possible to develop methods for the quantitative determination of epoxides using kinetic methods of analysis and UV–visible spectroscopy. [ABSTRACT FROM AUTHOR]

This study highlights the synergistic interplay between a Lewis acidic copper ion and a dissociated ligand from Cu(triNHC) complexes in the synthesis of cyclic carbonates from CO2 and epoxy compounds. The reactions were found to proceed efficiently under Cu(triNHC)‐catalyzed conditions, yielding significant quantities of cyclic carbonates across various epoxy substrates encompassing amine, sulfide, and ether functionalities. Stereochemical analyses underscore a pronounced propensity for retaining the stereochemistry of epoxy compounds in the resultant carbonates. This suggests a mechanism involving double inversion of stereochemistry during the reaction, which comprises catalyst‐mediated epoxide ring opening, subsequent CO2 addition, and carbonate ring closing. These findings align with established mechanisms for CO2 fixation reactions, shedding light on the intricate pathways underlying this catalytic process. [ABSTRACT FROM AUTHOR]

The aim of the article was to determine the effect of temperature on the tensile strength of two types of the epoxy compounds: the neat and the montmorillonite reinforced epoxy compounds. These epoxy compounds were made in four variants, which included two epoxy resins based on bisphenol A (unmodified base epoxy resin and modified with polyester resin epoxy resin) as well as two curing agents: triethylenetetramine and polyamide curing agent. The samples were exposed in two types of environment: (i) at 80°C for 1 and 2 months in a thermal chamber and also (ii) in the temperature range from −40°C to 80°C for 1 and 2 months in a thermal shock chamber. The reference samples of epoxy compounds were also compared. After the aging time, the dog-bone samples of epoxy compounds were subjected to the tensile strength tests in accordance with PN-EN ISO 527–2. The compressive strength of reference samples is higher for epoxy compounds containing the triethylenetetramine curing agent (both for epoxy compounds comprising Epidian 5 and Epidian 57 epoxy resin), The values of tensile strength, elongation at break are affected by the ambient and curing temperature, the curing period and the presence of a filler (montmorillonite). The tensile strength of the reference epoxy compounds containing Epidian 5 epoxy resin and the triethylenetetramine curing agent is lower than that of epoxy compounds containing unmodified epoxy resin (Epidian 5) and the polyaminoamide curing agent, while the tensile strength of the epoxy compounds containing modified epoxy resin (Epidian 57) and the triethylenetetramine curing agent is higher than that of the epoxy compounds containing Epidian 57 epoxy resin and the polyaminoamide curing agent. Aging of the epoxy compounds both in the climatic chamber and in the thermal shock chamber in most cases it contributed to an increase in the tensile strength. [ABSTRACT FROM AUTHOR]

The aim of this paper was to analyse the compressive strength and structure of epoxy adhesive compounds containing three different fillers with good thermal conductivity, additionally prepared in variants containing different amounts of these fillers. The base of epoxy adhesive compounds was a mixture of epoxy resin and polyamide curing agent. Three fillers: aluminium, graphite and copper were used in the study. The content of each filler in the epoxy adhesive compounds was 0.5 g, 1 g and 2 g per 100 g of epoxy resin. It allowed to compare the influence of the fillers on the compressive strength between the tested epoxy adhesive compounds and on the structure of the epoxy compounds based on SEM images. To accurately show the differences between the tested samples the one-way ANOVA test and POST-HOC test were used in the study. Descriptive statistic showed that adding the fillers in the amounts used in this research, increased the compressive strength of the epoxy adhesive compounds with the same filler. The results of this analysis showed that the epoxy adhesive compounds containing the aluminium and the copper do not show statistical significance between the amounts of the used filler. [ABSTRACT FROM AUTHOR]

Despite extensive research into developing efficient and environmentally friendly catalysts for converting CO2 over the last decade, the search for a robust and cost‐effective catalytic system is ongoing. This study describes developing and applying a new catalytic system using inexpensive ferrate and zincate anions immobilized on easily available commercial ion exchange resins (IER) to produce cyclic carbonates from CO2 with high efficiency and low cost. Two polystyrene‐based anion exchange resins, AmberlystTM A26‐Cl (A26‐Cl) and AmberliteTM IRA‐400‐Cl (IRA400‐Cl), were compared. The results demonstrated the catalysts' remarkable activity under mild conditions and demonstrated the synergistic effect between the polystyrene support and the active ammonium metallates, presenting a scalable, eco‐friendly method for cyclic carbonate production using waste CO2. A Design of Experiment (DoE) approach was implemented to optimize the catalytic cycloaddition of CO2. The reaction scale‐up to produce a 5 g batch of propylene oxide and conducting recycling tests demonstrated that the catalyst retained its activity over four cycles. The research also explored the use of various epoxides and found that terminal epoxides produced very good yields. In summary, this study introduces a cost‐effective, scalable method for converting CO2 into valuable cyclic carbonates, leveraging the synergistic effects of polystyrene supports and active ammonium metallates. [ABSTRACT FROM AUTHOR]

Despite extensive research into developing efficient and environmentally friendly catalysts for converting CO2 over the last decade, the search for a robust and cost‐effective catalytic system is ongoing. This study describes developing and applying a new catalytic system using inexpensive ferrate and zincate anions immobilized on easily available commercial ion exchange resins (IER) to produce cyclic carbonates from CO2 with high efficiency and low cost. Two polystyrene‐based anion exchange resins, AmberlystTM A26‐Cl (A26‐Cl) and AmberliteTM IRA‐400‐Cl (IRA400‐Cl), were compared. The results demonstrated the catalysts' remarkable activity under mild conditions and demonstrated the synergistic effect between the polystyrene support and the active ammonium metallates, presenting a scalable, eco‐friendly method for cyclic carbonate production using waste CO2. A Design of Experiment (DoE) approach was implemented to optimize the catalytic cycloaddition of CO2. The reaction scale‐up to produce a 5 g batch of propylene oxide and conducting recycling tests demonstrated that the catalyst retained its activity over four cycles. The research also explored the use of various epoxides and found that terminal epoxides produced very good yields. In summary, this study introduces a cost‐effective, scalable method for converting CO2 into valuable cyclic carbonates, leveraging the synergistic effects of polystyrene supports and active ammonium metallates. [ABSTRACT FROM AUTHOR]

We report a useful synthetic approach to assemble in/in epoxide, in/out epoxide, and out/out epoxide in cage systems using the Corey–Chaykovsky reaction and the Peterson olefination as key steps. In this regard, a variety of pentacycloundecane (PCUD) based cage compounds containing oxirane rings with diverse stereochemical disposition were synthesized via a simple synthetic sequence. Five cage diones were used for this purpose, and the starting cage diones were prepared with easily accessible starting materials such as 1,4-hydroquinone derivatives and cyclopentadiene. Here, we have used the Diels–Alder (DA) reaction, a [2+2] photocycloaddition, the Corey–Chaykovsky reaction, and the Peterson olefination as crucial steps to prepare the target molecules. [ABSTRACT FROM AUTHOR]

Nitriles are valuable compounds because they have widespread applications in organic chemistry. This report details the nickel-catalyzed reductive cyanation of aryl halides and epoxides with cyanogen bromide for the synthesis of nitriles. This robust protocol underscores the practicality of using a commercially available and cost-effective cyanation reagent. A variety of aryl halides and epoxides featuring diverse functional groups, such as -TMS, -Bpin, -OH, -NH2, -CN, and -CHO, were successfully converted into nitriles in moderate-to-good yields. Moreover, the syntheses at gram-scale and application in late-stage cyanation of natural products and drugs reinforces its potentiality. [ABSTRACT FROM AUTHOR]

The versatile reactivity of propargylic epoxides and alcohols, due to the presence of a triple bond, is used in the synthesis of various organic compounds and building blocks. However, there are not many known methods for the preparation of optically pure propargylic epoxides and alcohols, and the existing ones often require specific reagents. Halohydrin dehalogenases (HHDHs) can be used to obtain enantiomerically pure compounds from racemic epoxides. These important biocatalysts facilitate epoxide ring‐opening reactions with unnatural nucleophiles such as azides. Here we report the biocatalytic transformation of propargylic epoxides using HHDHs. Six propargylic epoxides with different substituents were synthesized. Kinetic resolution reactions catalyzed by HHDHs in the presence of azide were performed. Two enzymes with opposite stereoselectivities, HheC and HheA2‐N178A were used and yielded azido alcohols (98–>99% ee, E‐value >200) and epoxides (29–88% ee). The best performing p‐tolyl propargylic epoxide derivative was used in a sequence of two enzymatic reactions to obtain both enantiomers of the β‐azido alcohol and the (R)‐enantiomer of the α‐azido alcohol, each in >99% ee, through complete conversion of the starting epoxide. The obtained azido alcohols were used in further transformations. The click reactions with terminal acetylenes gave triazolyl propargylic alcohols (>99% ee, 90–98% yield). In the case of the α‐azido alcohol, the click reaction was followed by intramolecular cyclization to form the dihydrofuranyl triazole motif that is found in biologically active compounds. [ABSTRACT FROM AUTHOR]

We report a solid‐acid catalyzed aminolysis of epoxides under continuous‐flow conditions. A titania‐zirconia supported molybdenum oxide catalyst demonstrated exceptional substrate compatibility, enabling the synthesis of β‐amino alcohols in excellent yields with high catalyst durability. Characterization of the catalyst revealed the crucial role of the titania‐zirconia ratio in optimizing its performance. Furthermore, this method was applied to the efficient, sequential‐flow synthesis of a rivaroxaban intermediate (an oral anticoagulant and the first direct factor Xa inhibitor), combining a hydrogenation step with the aminolysis reaction without the need for intermediate isolation. [ABSTRACT FROM AUTHOR]

Cyclophellitol is a potent and selective mechanism‐based retaining β‐glucosidase inhibitor that has served as a versatile starting point for the development of activity‐based glycosidase probes (ABPs). We developed routes of synthesis of eight mono‐ and dideoxycyclophellitols and cyclophellitol aziridines, the latter as ABPs carrying either a biotin or fluorophore linked to the aziridine nitrogen. We reveal the potency of these 24 compounds as inhibitors of the three human retaining β‐glucosidases, GBA1, GBA2 and GBA3. We show that 3,6‐dideoxy‐β‐galacto‐cyclophellitol aziridine selectively captures GBA3 over GBA1 and GBA2 in extracts of cells overexpressing both GBA2 and GBA3. We also identify a probe that selectively labels GBA1 and GBA2 over GBA3 at lower concentrations. In sum, the here‐presented studies reveal new chemistries to prepare chiral, substituted cyclitol epoxides and aziridines, add to the growing suite of cyclophellitols varying in configuration and substitution pattern, and yielded a reagent that may find use to investigate the physiological role and therapeutic relevance of the most elusive of the three retaining β‐glucosidases: GBA3. [ABSTRACT FROM AUTHOR]

Here, we introduce a new class of titanocene catalysts for epoxide hydrosilylation that frustrates their hydridicity and thereby emphasizes their electron transfer reactivity. This unique attenuation of hydridicity is accomplished by introducing Lewis acidic silicon centers to the cyclopentadienyl ligands for an intramolecular coordination of the titanium‐bound hydride. The superiority of our rationally designed catalysts over classic titanocenes with alkyl‐substituted cyclopentadienyl ligands is demonstrated in the dramatically improved regioselectivity of the hydrosilylation of monosubstituted epoxides to primary alcohols. [ABSTRACT FROM AUTHOR]

Composite materials are gaining popularity due to their better mechanical qualities and low weight. This study focuses on enhancing forces of flexural and tensile characteristics in epoxy-based composites by incorporating reinforced carbon fibers extracted from pineapple leaves in combination with cobalt filler. The reinforcement of natural fibers in composite materials addresses environmental concerns and contributes to improved mechanical attributes. Hand lay-ups of pineapple leaf fiber (PALF) and epoxy compound by carbon fiber were created proportion of weight (wt%) by adjusting cobalt 0.25 to 1.0 wt%. The flexural strength of PALF is around 101 MPa, and the Tensile strength of PALF is around 92.94 MPa. Whereas the Flexural strength of CF is around 343.54 MPa, and the Tensile strength of CF is around 181.32 MPa. Compared to pure epoxy, 51.25% increased strength and considerable improvement of flexural and tensile specimens. 0.5 wt% inclusion of nano Cobalt filler component confirms favorable strength test findings in PALF/CF epoxy combination. [ABSTRACT FROM AUTHOR]

Epoxy resin has many advantages. However, as a matrix resin for composites, epoxy resin has the weakness of high viscosity, poor fluidity and low processing time. Considering the high viscosity and poor storage ability of the traditional epoxy prepolymer, we designed an epoxy resin formulation possessing both certain mechanical strength and fluidity. We utilized a low-viscosity trifunctional epoxy compound, N,N-diglycidyl-4-glycidyloxyaniline (AFG), and a solid-liquid mixture of low-eutectic anhydrides, specifically 4-methyl tetrahydro phthalic anhydride and 1,2,3,6-tetrahydrophthalic anhydride, as the epoxy monomers and curing agents, respectively. More importantly, when stored at room temperature for 3 h, this mixture exhibited a low viscosity (1000 mPa·s), which was attributed to the solid-liquid mixed anhydrides remaining in a liquid state at room temperature without recrystallizing. Then, a series of epoxy resins were designed by controlling the mole ratio of epoxide groups to anhydride groups. These resins were analyzed through mechanical property experiments and thermal analysis. The results showed a wide range of adjustable crosslink density in the epoxy resin, from 2 000 mol/m³ to 6 000 mol/m³, and the establishment of a relationship between network, mechanical, and thermal properties of the epoxy resin. This epoxy resin was successfully applied to prepare composites by the unidirectional tape prepreg process. Moreover, the ester bonds can be triggered with transesterification behavior under the zinc(II) acetylacetonate catalyst with hydroxyl group. Therefore, epoxy resins can be completely degraded by ethylene glycol at 180 ℃ for 6 h. A wide range of mechanical and thermal properties can be achieved by controlling the ratio of epoxide groups to anhydride groups in epoxy resins, which provides a certain reference for the development of low-viscosity epoxy resins. [ABSTRACT FROM AUTHOR]

Nowadays, Manufacturing and automotive industries have begun to employ renewable resources as a result of public awareness and rigorous legal requirements relating to the usage of polymers. This study has focused on employing Snake Grass (SG) fiber as reinforcement in Aegle Marmelos with Epoxy blended hybrid matrix (AME), since natural fiber reinforced composites provide a significant role in the development of lightweight structural components. The primary study investigated the effects of fibre length and fibre volume percentage on the mechanical properties of snake grass fibre. Based on the test results, the composite with a 15 mm fibre length and a volume percentage of 20% SG fiber has better mechanical qualities. Finally, mechanical and dynamic mechanical properties are used to assess the impact of Aegle marmelos with Epoxy blended hybrid matrix addition into the snake grass fibre composite. The inclusion of natural fiber with epoxy matrix and natural (Aegle marmelos) filler increased composite character istics due to their synergistic effect. This enhances the adhesion and stress transmission uniformity between the reinforcements. The morphology of the fiber surface is assessed using micrographs acquired with a scanning electron microscope. [ABSTRACT FROM AUTHOR]

Fan-out (FO) packages are in high demand for smartphones and Internet of Things (IoT) devices because they allow for the integration of multiple components within a single package, leading to enhanced functionality and improved operational performance. In addition, the shift from solder bumps to copper pillar bumps for interconnection is expected to become a prevalent trend in FO package assemblies because of their superior electrical and thermal performance and ability to achieve a finer pitch. However, the increased stiffness of the copper pillars increases the risk of interface fractures between the pillars and solder bumps during the surface mount technology process, which may degrade the thermal cycle test (TCT) reliability. Consequently, the present study develops a three-dimensional (3D) computational model, which approximates the thermomechanical properties of the redistribution layer (RDL) using the rule of mixtures principle, to analyze the reliability of the Cu pillar bumps in FO packages under thermal cycling between −55°C and 125°C. The tensile stress–strain properties of the polyimide (PI) film in the FO package are determined experimentally using an MTS Acumen microforce tester. The experimental data are used to construct an empirical formula for predicting the stress–strain response of the PI film, which is then incorporated into the simulation model. The validity of the simulation model is confirmed by comparing the predicted results for the out-of-plane deformation of the FO package with experimental observations. The reliability of the Cu pillar bumps under TCT processing is investigated numerically using the Anand viscoplastic constitutive model. Finally, a second-order response surface methodology model and Box–Wilson central composite design method are employed to determine the optimal design of the FO package that minimizes the plastic work density of the Cu pillar bumps. The results show that the thermomechanical reliability of the FO package depends mainly on the Cu trace coverage in the RDL and the thickness of the epoxy molding compound layer. [ABSTRACT FROM AUTHOR]

The lipid content of skin plays a determinant role in its barrier function with a particularly important role attributed to linoleic acid and its derivatives. Here we explored the consequences of interfering with the soluble epoxide hydrolase (sEH) on skin homeostasis. sEH; which converts fatty acid epoxides generated by cytochrome P450 enzymes to their corresponding diols, was largely restricted to the epidermis which was enriched in sEH-generated diols. Global deletion of the sEH increased levels of epoxides, including the linoleic acid-derived epoxide; 12,13-epoxyoctadecenoic acid (12,13-EpOME), and increased basal keratinocyte proliferation. sEH deletion (sEH-/- mice) resulted in thicker differentiated spinous and corneocyte layers compared to wild-type mice, a hyperkeratosis phenotype that was reproduced in wild-type mice treated with a sEH inhibitor. sEH deletion made the skin sensitive to inflammation and sEH-/- mice developed thicker imiquimod-induced psoriasis plaques than the control group and were more prone to inflammation triggered by mechanical stress with pronounced infiltration and activation of neutrophils as well as vascular leak and increased 12,13-EpOME and leukotriene (LT) B4 levels. Topical treatment of LTB4 antagonist after stripping successfully inhibited inflammation and neutrophil infiltration both in wild type and sEH-/- skin. While 12,13-EpoME had no effect on the trans-endothelial migration of neutrophils, like LTB4, it effectively induced neutrophil adhesion and activation. These observations indicate that while the increased accumulation of neutrophils in sEH-deficient skin could be attributed to the increase in LTB4 levels, both 12,13-EpOME and LTB4 contribute to neutrophil activation. Our observations identify a protective role of the sEH in the skin and should be taken into account when designing future clinical trials with sEH inhibitors.

Herein, we have reported an effective protocol for the regioselective transfer hydrogenation (TH) of epoxides by utilizing a phosphine‐free bis‐NHC−Mn(I) complex and ammonia borane. By employing this strategy, aromatic epoxides were selectively converted to primary alcohols whereas secondary alcohols were obtained exclusively from aliphatic epoxides. The protocol was further extended for the TH of azoarenes and nitroarenes to hydrazoarenes and anilines respectively. Notably, a library of substrates with different functional groups were screened which resulted in the corresponding transfer hydrogenated product in good to excellent yields. A series of mechanistic investigations were carried out to understand the catalytic process. [ABSTRACT FROM AUTHOR]

Chiral organofluorine compounds featuring a monofluoromethyl (CH2F)-substituted stereocenter are often encountered in a number of drugs and bioactive molecules. Consequently, the development of catalytic asymmetric methods for the enantioselective construction of CH2F-substituted stereocenters has made great progress over the past two decades, and a variety of enantioselective transformations have been accordingly established. According to the types of fluorinated reagents or substrates employed, these protocols can be divided into the following major categories: (i) enantioselective ring opening of epoxides or azetidinium salts by fluoride anions; (ii) asymmetric monofluoromethylation with 1-fluorobis(phenylsulfonyl)methane; (iii) asymmetric fluorocyclization of functionalized alkenes with Selectfluor; and (iv) asymmetric transformations involving α-CH2F ketones, α-CH2F alkenes, or other CH2F-containing substrates. This feature article aims to summarize these recent advances and discusses the possible reaction mechanisms, advantages and limitations of each protocol and their applications. Synthetic opportunities still open for further development are illustrated as well. This review article will be an inspiration for researchers engaged in asymmetric catalysis, organofluorine chemistry, and medicinal chemistry. [ABSTRACT FROM AUTHOR]

A Palladium catalyzed C4‐ alkylation of indoles using epoxide as an alkylating agent and pivaloyl as a weak chelating group has been demonstrated. A variety of substituted epoxides and indoles furnished the desired β‐indolylethyl alcohols in 38%–87% yields. Control experiments indicate that the C−H cleavage step is irreversible. The resultant hydroxyl group has been converted to various functional groups to demonstrate the synthetic utility of this protocol. [ABSTRACT FROM AUTHOR]

The sequestration of atmospheric CO2 into value-added products is of great interest from economic and environmental perspectives. The tetra-shelled Cr1.3Fe0.7O3 hollow sphere as a heterogeneous catalyst was synthesized by a simple hydrothermal method followed by calcination at 600 °C. The synthesized tetra-shelled hollow spheres were characterized by several effective tools. The catalytic performance was studied for the cycloaddition reaction of CO2 with epoxides under solvent-free conditions. The reaction time, reaction temperature, CO2 pressure, and the catalyst amount were systematically studied. Under the best-experimented condition (0.02 g of the catalyst, 80 °C, 6 h, and 4 bar CO2 pressure), the catalyst demonstrated a broad substrate scope and functional group tolerance. Besides, the catalyst showed high recycling efficiency for five consecutive reaction cycles with no significant decline in activity. [ABSTRACT FROM AUTHOR]

The synthesis of copper nanocrystals on tartaric acid jute composite surface is reported. The formation of nanocrystals is detected by FT IR, Powder X‐ray diffraction, SEM, and TEM analysis. The average size of the nanocrystals is found to be 500 nm. The reaction of the copper nanocrystals with CO2 resulted in a decrease in the size of the nanoparticles. Cycloaddition reaction of epoxides to cyclic carbonate is efficiently carried out by the copper nanocrystals on tartaric acid jute composite surface (CUNPJT) without using any cocatalyst and solvent. To the best of author's knowledge, this is the first example of copper nanocrystals catalyzing the cycloaddition of CO2 and epoxide. [ABSTRACT FROM AUTHOR]

A synthetic protocol for the preparation of novel 3,4‐pyrrolidine‐fused β‐lactams was developed. The proposed 2,6‐diazabicyclo[3.2.0]heptan‐7‐one scaffolds were constructed through an amido group‐induced, potassium tert‐butoxide‐promoted intramolecular ring closure of 3‐acylamino‐4‐oxiranyl‐β‐lactams as the key reaction step. Alternatively, the desired cyclization was also effected by means of a scandium triflate‐mediated catalytic approach. In this way, a set of stereodefined 3,4‐pyrrolidine‐fused β‐lactams was synthesized, which were preliminary evaluated as β‐lactamase inhibitors. These first‐line biological assessments led to the identification of a 2‐benzoyl‐6‐(4‐methoxyphenyl)‐substituted diazabicyclo structure as an eligible starting point for further β‐lactamase inhibitor optimization studies. [ABSTRACT FROM AUTHOR]

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Cr(III) metal centers have been successfully incorporated in the terephthalaldehyde-triaminoguanidium chloride COP, Te-TGCl. Free COP, Te-TGCl and metalated COP, Te-TG-Cr(III) were characterized with the help of various techniques, viz., FT-IR, 13C CP-MAS NMR, PXRD, XPS, FESEM, SEM-EDX, HR-TEM, TGA and BET. Due to the presence of the Lewis acidic Cr(III) center, Te-TG-Cr(III) showed superior activity (ECH, 99% conv.) compared to non-metalated COP, Te-TGCl (ECH, 75% conv.) in the cycloaddition reaction of CO2 to epoxides, which resulted in chemically valuable cyclic carbonate products. Moreover, compared to Cr(NO3)3·9H2O (ECH, 45% conv.), COP-immobilized Cr(III), Te-TG-Cr(III), shows much higher activity (ECH, 99% conv.), signifying the importance of COP in the enhancement of catalytic activity. Moreover, Te-TG-Cr(III) discriminates the substrates on the basis of the length of the epoxide side chains, showing much higher conversions for smaller substrates ECH and EBH (99% and 96% conv., respectively) compared to larger substrates BGE, AGE, PGE, EH and SO (68%, 60%, 69%, 57% and 35% conv., respectively). [ABSTRACT FROM AUTHOR]

The past few decades have witnessed tremendous development within epoxides. Among the many known reactions involving epoxide, Meinwald rearrangements represent one of the most important and attractive approaches, which can transform epoxides into versatile carbonyl compounds. Given the high efficiency of this protocol, substantial efforts have been made by researchers by utilizing multiple catalyst systems. This review provides an overview of recent advances in the Meinwald rearrangement (from 2014 onward), along with detailed discussions on mechanistic insights. This review aims to highlight the importance and value of these methodologies, thereby promoting further investigation and application. [ABSTRACT FROM AUTHOR]

Dendritic ZSM-5 zeolites were investigated in the isomerization of monoterpene epoxides, including limonene-1,2-epoxide (LE), α-pinene epoxide, and β-pinene epoxide, which yields high-value compounds used in fragrances, cosmetics, and pharmaceuticals. The fresh catalysts were thoroughly characterized using XRD, Ar physisorption, pyridine-FTIR, TEM, FTIR/DTBPyr, and 27Al MAS NMR. In comparison with conventional and hierarchical ZSM-5 materials, the dendritic zeolite with a crystallization time of 4 days (d-ZSM-5/4d) was the most active material, with a turnover frequency value of 4.4 min−1 for LE isomerization. Likewise, remarkable yields of dihydrocarvone (DHC, 63%, 70 °C, 2 h), campholenic aldehyde (72.4%, 70 °C, 5 min), and myrtanal (47.7%, 50 °C, 5 min) were obtained with this material that exhibited the largest mesopore/external surface area (360 m2 g−1), showing also the narrowest mesopore size distribution. A direct relationship was observed between the TOF values and the concentration of external Brønsted acid sites, showing the presence of strong steric/diffusional limitations that are greatly overcome with the dendritic zeolites. The lower reactivity of trans-LE compared to cis-LE was attributed to the larger steric hindrance of the oxygen atom. Exploration of the solvent influence revealed that the reaction rate of LE was favored by non-polar solvents, while highly selective DHC formation occurred in the solvents of medium polarity. The d-ZSM-5/4d sample was shown to be robust because catalytic activity could be completely recovered by air calcination. [ABSTRACT FROM AUTHOR]

Cycloaliphatic epoxides exhibit post‐light irradiation heat‐induced polymerization, creating warp‐resistant green bodies during sintering. However, their use in light polymerization three‐dimensional (3D) printing is limited by slow photo‐curing speeds. In this study, a photo‐cationic polymerizable ceramic slurry was developed for 3D printing by mixing oxetane with cyclo‐aliphatic epoxide. This mixture improved photo‐curing speed, reduced resin viscosity, and enhanced the ceramic slurry's solid content. Additionally, we optimized the slurry by considering the specific and content ratio of photosensitizers and light absorbers. The optimized slurry polymerized unreacted functional groups in the polymer, improving the fracture strength of the green bodies through enhanced crosslinking density and uniformity in each layer. Ultimately, a sintered body without warpage was produced by the improved green bodies. This approach provides a solution related to controlling the photocuring speed and expands the potential applications of 3D printing in areas where the precision and stability of the printing material are required. [ABSTRACT FROM AUTHOR]

Various configurations of adhesive joints exist, each with unique characteristics. In the case of peel load solicitations, T-joints are the most common choice but are not sufficiently addressed in the literature, especially regarding the geometrical and material influence on their performance. Recently, meshless methods, like the Radial Point Interpolation Method (RPIM), have been used as alternatives to the Finite Element Method (FEM) for investigating joint behaviours. The present work aims to study the free length (FL) effect in T-joints, which is related to substrate stiffness. Three distinct FL dimensions were evaluated. At the same time, the effect of tp2 and adhesive type were taken into account. Initially, joint strength (Pmax) was predicted using two numerical approaches: FEM and RPIM, both employing elastic-plastic material models. Subsequently, the results were compared with the experimental data. Moreover, two yield criteria were considered to analyse the adhesive: von Mises and the Exponential Drucker-Prager criteria. The data resultant from this first phase was then used to select the correct yield criterion for evaluating the influence of FL in the adhesive joints. The methodology was validated, and then geometrical and material design recommendations were presented for the efficient use of T-joints in structural applications. [ABSTRACT FROM AUTHOR]

We present the use of an amine functionalized two-dimensional clay i.e., aminoclay (AC), in the chemistry of a three-dimensional metal–organic framework (MOF) i.e., MIL-101(Cr), to prepare MIL-101(Cr)/AC composites, which are exploited as catalysts for efficient conversion of CO2 gas into cyclic carbonates under ambient reaction conditions. Three different MOF nanocomposites, denoted as MIL-101(Cr)/AC-1, MIL-101(Cr)/AC-2, and MIL-101(Cr)/AC-3, were synthesized by an in situ process by adding different amounts of AC to the precursor solutions of the MIL-101(Cr). The composites were characterized by various techniques such as FT-IR, PXRD, FESEM, EDX, TGA, N2 adsorption, as well as CO2 and NH3-TPD measurements. The composites were exploited as heterogeneous catalysts for CO2 cycloaddition reactions with different epoxides and the catalytic activity was investigated at atmospheric pressure under solvent-free conditions. Among all the materials, MIL-101(Cr)/AC-2 shows the best catalytic efficiency under the optimized conditions and exhibits enhanced efficacy compared to various MIL-101(Cr)-based MOF catalysts, which typically need either high temperature and pressure or a longer reaction time or a combination of all the parameters. The present protocol using MIL-101(Cr)/AC-2 as the heterogeneous catalyst gives 99.9% conversion for all the substrates into the products at atmospheric pressure. [ABSTRACT FROM AUTHOR]

Employing enzymatic reaction cascade principles to synthesize artificial materials with multiple autonomously operating active sites is one of the holy grails in modern catalysis research. In this regard, metal–organic frameworks (MOFs) are promising host platforms. Yet, applying MOFs as enzyme‐mimicking catalysts is synthetically challenging. Herein, we present a design strategy for the synthesis of porphyrin‐based MOFs for the cascade catalysis of the conversion of olefins to epoxides and their cycloaddition with CO2 to cyclic carbonates. The MOFs feature tunable dual active sites with synthetically controllable metal variations. A clear dependence of the metal combination on the catalytic performance of the MOF catalysts is shown. This work advances the understanding essential for designing sophisticated, multifunctional porphyrin MOFs for efficient one‐pot cascade catalysis. [ABSTRACT FROM AUTHOR]

This study presents an organocatalytic C−H functionalization approach for postpolymerization modification (PPM) of poly(ethylene oxide) (PEO). Most of PEO PPM is previously processed at the end hydroxy group, but recent advances in C‐H functionalization open a way to modify the backbone position. Structurally diverse carboxylic acids are attached to PEO through a cascade process of radical generation by peroxide and oxidation to oxocarbenium by tertiary butylammonium iodide. Attaching carboxylic acids yields a series of functionalize PEO with acetal units (2−5 mol%) in a backbone, which is not accessible via conventional copolymerization of epoxides. The optimized conditions minimizes the uncontrolled degradation or crosslinking from the highly reactive radical and oxocarbenium intermediate. The newly introduced acetal units bring degradability of PEO as well as delivery of carboxylic acid molecules. Hydrolysis studies with high molecular weight functionalization PEO (Mn = 13.0 kg mol−1) confirm the steady release of fragmented PEO (Mn ∼ 2.0 kg mol−1) and carboxylic acid over days and the process rate is not sensitive to pH variation between pH 5 and 9. The presented method offers a versatile and efficient way to modify PEO with potential energy and medical applications. [ABSTRACT FROM AUTHOR]

Ambient condition-determined chemical CO2 fixation affords great promise for remitting the pressure of CO2 release. The construction of a microporous environment easily captures CO2 molecules around the reactive sites of the catalyst to reinforce the reaction process. Herein, multi-hydroxyl-containing hyper-crosslinked organic polymers (HCPs-OH-n) are synthesized by the polymerization of 1,4-dichlorobenzyl (DCX) and m-trihydroxybenzene in the monosaccharide form in a Friedel–Crafts alkylation hypercrosslinking process (FCAHP). By tuning the DCX ratio in the FCAHP, the structural properties can be regulated to create a more microporous surface in the HCPs-OH-n; meanwhile, the formed multi-hydroxyl species in the microporous environment could induce the easy interaction between hydroxyls and epoxides by forming a hydrogen bond, which improves the activation of epoxides during the cycloaddition reaction to synthesize the cyclic carbonates at ambient conditions. The structural properties suggest that HCPs-OH-n possess a large surface area with appreciable microporous and mesoporous distribution. As expected, the HCPs-OH-3 bearing the most abundant mesoporosity affords the highest reactivity in the chemical CO2 fixation to cyclic carbonates and is endowed with rational recoverability. [ABSTRACT FROM AUTHOR]

Immense gains in understanding of mechanisms and effects of lipid oxidation have been achieved in the nearly 90 years over which lipid oxidation has been an active research focus. Even so, the substantial questions still being raised about lipid oxidation in this special issue show clearly that missing pieces remain and must be considered for full accounting of this important reaction in any system. In this context, epoxides are spotlighted as a critical overlooked product of lipid autoxidation – underestimated in analysis, underestimated in presence as a functionally active and competitive intermediate and product of lipid oxidation, and underestimated in potential contributions to impact of lipid oxidation on other molecules and cell functions. Logical reasons for ignoring or not finding epoxides are offered in historical development of lipid oxidation knowledge. Reactions generating lipid epoxides in autoxidation are reviewed, limitations in detecting and tracking epoxides are outlined to explain why epoxides may not be detected when they should be present, and justifications for increased research and analysis of epoxides are argued. The main goal is to provide a context for recognizing epoxides as critical products that must be accounted for in determining the state rather than extent of lipid oxidation and in tracking its consequences in oils, foods, personal care products, and tissues. A secondary goal is to stimulate new research using contemporary analyses to fill in the gaps of knowledge about epoxide formation, structure, and reactions in lipid autoxidation. [ABSTRACT FROM AUTHOR]

The crystalline sponge method has proven invaluable in the preparation and analysis of supramolecular host/guest complexes if the host can be obtained in a suitable crystalline form, allowing the analysis of guest binding modes inside host cavities which can inform other studies into processes such as catalysis. Here, we report the structures of a set of ten host/guest complexes using an octanuclear coordination cage host with a range of small-molecule neutral organic guests including four aromatic aldehydes and ketones, three cyclic lactams, and three epoxides. In all cases, the cavity-bound guests are anchored by a collection of CH•••O hydrogen-bonding interactions between an O atom on the guest and a convergent set of CH protons at a pocket on the cage interior surface. Depending on guest size and the presence of solvent molecules as additional guests, there may be one or two cavity-bound guests, with small aromatic guests forming π-stacked pairs. Some guests (the lactams) participate in additional NH•••F H-bonding interactions with surface-bound fluoroborate anions, which indicate the type of anion/guest interactions thought to be responsible for solution-phase catalytic reactions of bound guests. [ABSTRACT FROM AUTHOR]

This study investigated the manufacturing processes for structural supercapacitors (SSCs) using smear molding (RS), resin transfer molding (RTM), and vacuum-assisted resin transfer molding (VARTM). Woven carbon fibers were used as the electrode, woven glass fibers as an insulating layer, and an alkaline/epoxy compound as the electrolyte. In the RTM process, due to the vacuum and the high-pressure injection of the electrolyte, the electrochemical and mechanical properties of the SSC can be greatly improved, and the void contents in the SSC can be reduced. The balanced electrochemical performance and mechanical properties of SSCs were observed in the range of epoxy content from 15 wt% to 30 wt%. This study contributes to the development of SSCs through the establishment of the fabrication process for improvements in part quality. The fabrication method demonstrated here can be directly applied by industries to produce even larger-scale SSCs, opening up new possibilities for practical implementation and scalability. [ABSTRACT FROM AUTHOR]

H-bond donor (HBD) catalysis is essential in the cycloaddition of CO2 with epoxide (CCE) where a strong HBD is prevalent; however, current C–H H-bond donors are extremely weak and scarcely viable in catalysis. We reveal sulfonium featuring multiple α-C–H bonds as a new type of efficient HBD catalyst in the CCE reaction. Two series of cyclic tertiary sulfoniums were designed and evaluated in the cycloaddition of CO2 to epoxide. An optimal S-alkyl tetrahydrothiophenium bromide (THT3-Br) catalyst converted epoxides to the corresponding cyclic carbonates with high conversion (>90%) and near quantitative selectivity (99%) in 6 h under 1 MPa pressure of CO2, at 100 °C, and with 5 mol% loading. NMR titration confirmed the triple H-bonding of the α-C–H of sulfonium to epoxide, which activated the substrate oxirane and facilitated bromide attack on the methylene carbon. The first observation of sulfonium in catalytic CCE reactions suggested a wider application of C–H H-bonding catalysis in carbon dioxide fixation. [ABSTRACT FROM AUTHOR]

Arylazo sulfones were used as Photoacid Generators (PAGs) for the visible-light photorelease of strong sulfonic acids to promote the ring opening of epoxides in benign media (DMC/water mixtures) or under neat conditions. Water, alcohols, azide and thiocyanate anions, as well as electron-rich aromatics were used in the role of the nucleophile. The resulting 1,2-disubstituted adducts were formed mostly in >99% yield in a high regioselective fashion. [ABSTRACT FROM AUTHOR]