Search

The chemistry of platinum(II) and platinum(IV) with the ligands 3,4,5-tris(2-pyridyl)-4-H-1,2,4-triazole, L1, and 3,5-di(2-pyridyl)-4-(4-pyridyl)-4-H-1,2,4-triazole, L2, is described. The ligand L1 forms platinum(II) complexes [PtXY(κ2-N, N′-L1)] (X, Y = Cl, Cl; Cl, Me; Me, Me) by chelation while ligand L2 forms either analogous chelate complexes [PtXY(κ2-N, N′-L2)] (X, Y = Cl, Me; Me, Me) or acts as a monodentate ligand in forming trans-[PtCl2(SMe2)(κ1-N-L2)], in which only the 4-pyridyl group is coordinated. The electron-rich dimethylplatinum(II) complexes undergo oxidative addition reactions with methyl iodide to give [PtIMe3(κ2-N, N′-L1)], or with dichloromethane to give [PtClMe2(CH2Cl)(κ2-N, N′-L1)] or [PtClMe2(CH2Cl)(κ2-N, N′-L2)], each of which is formed as a mixture of three isomers. Structure determinations of several of these complexes are reported. [ABSTRACT FROM AUTHOR]

Bimetallic (Ta/Ti, V, Co, Nb) mesoporous MCM-41 nanoparticles were obtained by direct synthesis and hydrothermal treatment. The obtained mesoporous materials were characterized by XRD, XRF, N2 adsorption/desorption, SEM, TEM, XPS, Raman, UV-Vis, and PL spectroscopy. A more significant effect was observed on the mesoporous structure, typically for MCM-41, and on optic properties if the second metal (Ti, Co) did not belong to the same Vb group with Ta as V and Nb. The XPS showed for the TaTi-MCM-41 sample that framework titanium is the major component. The new nanoparticles obtained were used as catalysts for oxidation with hydrogen peroxide of olefinic compounds (1,4 cyclohexadiene, cyclohexene, styrene) and photodegradation of organic pollutants (phenol, methyl orange) from water. The results showed improvementsin activity and selectivity in oxidation reactions by the addition of the second metal to the Ta-MCM-41 catalyst. The slow addition of H2O2 was also beneficial for the selectivity of epoxide products and the stability of the catalysts. The band gap energy values decreased in the presence of the second metal, and the band edge diagram evidenced positive potential for all the conduction bands of the bimetallic samples. The highestlevels of photocatalytic degradation were obtained for the samples with TaTi and TaV. [ABSTRACT FROM AUTHOR]

The oxygen initiation process, one of the key processes in the early stage of the autothermic pyrolysis insitu conversion technology, has not been deeply investigated, which seriously limits its development. In this study, the reaction behaviors, kinetic parameters, heat and product release characteristics during the isothermal oxygen initiation process of Huadian oil shale in O2/N2 mixtures with different oxygen concentrations and initiation temperatures were investigated via TG/DSC-FTIR. The results show that the samples exhibit three different reaction behaviors during the initiation stage, consisting of two main parts, i.e., the oxidative weight-gain and the oxidative reaction phases. The former phase is mainly characterized by the oxygen addition reaction that produces oxidizing groups which increase the sample mass. And the latter stage consists of two main subreactions. The first subreaction involves the oxidative cracking and pyrolysis of oxidizing groups and kerogen to produce fuel deposits such as residual carbon, while the second subreaction focuses on the oxidation of the resulting fuels. Furthermore, increasing the oxygen concentration significantly promotes the above reactions, leading to an increase in the reaction intensity and reaction rate. Owing to the combined effect of oxygen concentration and residual organic matter content, the total heat release increases with the increasing initiation temperature and reaches its maximum at 330e370°C. In addition, the preheating stage primarily produces hydrocarbon gases, while the initiation stage predominantly generates CO2. As the preheating temperature increases, the CO2 output intensifies, the required reaction time shortens, and the release becomes more concentrated. Based on these findings, a reaction mechanism for the oxygen initiation process of Huadian oil shale was proposed, and recommendations were provided for optimizing the construction process. [ABSTRACT FROM AUTHOR]

1-Methylnaphthalene is a critical component for constructing fuel surrogates of diesel and aviation kerosene. However, the reaction pathways of 1-methylnaphthalene included in existing detailed chemical kinetic models vary from each other, leading to discrepancies in the simulation of ignition and oxidation processes. In the present study, reaction classes and pathways involved in the combustion of 1-methylnaphthalene were analyzed, and effects of rate constants of reactions related to 1-methylnaphthalene and its significant intermediates on ignition delay times and species concentration profiles were discussed, involving hydrogen abstraction and substitution reactions of 1-methylnaphthalene, oxidation, isomerization, and addition reactions of 1-naphthylmethyl, hydrogen abstraction and oxidation reactions of indene, as well as the oxidation of indenyl and naphthalene. On this basis, a new detailed chemical kinetic model for 1-methylnaphthalene was developed, which includes 1389 species and 7185 reactions. The validation of this mechanism shows that it can predict accurately the available experimental ignition delay times, species concentration profiles, and laminar flame speeds of 1-methylnaphthalene. Finally, reaction paths and sensitivity analysis of ignition delay times were performed using the proposed reaction mechanism, and the result shows that the conversion of 1-methylnaphthalene to 1-naphthaldehyde plays an important role in its ignition. [ABSTRACT FROM AUTHOR]

This article reports the preparation of a novel functionalized magnetic nanoadsorbent through an addition reaction between Fe3O4 nanoparticles coated with allyl silica gel and 4-pyridinyl ethylene. A detailed characterization of Fe3O4@SiO2-yl-VP was conducted. Among them, in the infrared spectrum, we can easily see that the absorption peak of the C=C stretching vibration at 1660 cm−1 in the raw material disappears after the addition reaction, indicating the successful grafting of polymer on the surface of silica gel. The appearance of N element in the EDS spectrum also proves the successful completion of the addition reaction and the successful synthesis of Fe3O4@SiO2-yl-VP. At pH = 5 and pH = 7, it only takes half an hour for Fe3O4@SiO2-yl-VP to achieve maximum adsorption capacities of 85.06 and 73.78 mg/g for Hg (II) and Pb (II), respectively. The adsorption process conforms to the Langmuir model and the pseudo-first- and pseudo-second-order kinetic models and can be reused 11 times, demonstrating excellent reusability. [ABSTRACT FROM AUTHOR]

Aiming at the problem of excessive swelling of conventional microspheres for oilfield use, a novel amphiphilic polymerizable crosslinker (AE) was synthesized by quaternary ammonium modification of an unstable crosslinker (AE) using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid as the monomers, N,N′-methylene bisacrylamide as the stabilizing crosslinker, ammonium peroxysulfate and sodium bisulfite as the initiator, and water as the solvent by using a reversed microemulsion method. Double-networked nanomicrospheres were prepared. The preparation conditions of the microspheres were optimized by the surface response method, focusing on the effects of the initiator addition and reaction temperature, and total crosslinker addition on the formation of nanomicrospheres. The samples were characterized by FTIR, TGA, laser particle sizer, and SEM to evaluate the retarded expansion performance and the modulation drive performance. The results showed that the optimal conditions for the preparation of microspheres were m(oil phase):m(water phase) = 3:2, stirring speed of 550 r/min, total crosslinking agent dosage of 0.6% (based on the total mass of monomers, hereinafter the same), initiator dosage of 0.30%, reaction temperature of 45 °C, and reaction time of 4 h. Compared with the conventional polymer microsphere PAM, PAE was slow-expanded for 45 d at 60 °C, and the expansion multiplier was about 16 times, with slow-expansion characteristics; the blocking rate of PAE reached 98.3%, the oil repulsion rate was 73.11%, and the increase in the recovery rate could be up to 11.23%. In this paper, a new type of nanomicrosphere material is investigated to realize the efficient implementation of oil field conditioning and driving. [ABSTRACT FROM AUTHOR]

Methyl-4-isothiazolin-3-one (MIT) is widely used in industrial production, but its persistence and potential biological toxicity in water environment have attracted widespread attention. Therefore, based on a Venturi tube cavitation reactor, a study was conducted on the process of oxidative degradation of methyl isothiazolinone using hydraulic cavitation technology combined with H2O2. With the aim of improving the degradation rate of MIT, the reaction time, inlet pressure, H2O2 addition amount, and MIT initial concentration were optimized. Through a series of experiments, the optimal reaction conditions were determined as follows: under the conditions of reaction time of 40 min, inlet pressure of 0. 5 MPa, H2O2 addition amount of 5 mL/L, and MIT initial concentration of 15mg/L, the degradation rate of MIT reached 69%. In order to gain a deeper understanding of the degradation mechanism of MIT, Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) technology was used to analyze the intermediate products of MIT degradation, and to speculate on the degradation process of MIT under this process condition. MIT mainly degrades its five membered ring structure through oxidation and addition reactions. This indicates that under the current experimental conditions, the degradation rate of MIT has reached a stable level, and further improving the degradation efficiency may require adjusting other parameters. On this basis, the initial rate method was used to determine that the degradation reaction of MIT under this process condition is a zero order reaction, that is, the reaction rate is not related to the concentration of MIT, but is influenced by other factors. Using the Coast Redfern model, the apparent activation energy of MIT was estimated to be 31. 127 kJ/mol, providing an important basis for further optimizing the degradation process. [ABSTRACT FROM AUTHOR]

A thorough understanding of the lignin–carbohydrate complex (LCC) structure has a significant meaning in the high-value utilization of lignocellulose. In this work, the complex (DHPKGC) was obtained by an addition reaction between konjac glucomannan (KGM) and quinone methides generated in the synthesis of dehydrogenation polymers (DHPs) to simulate the formation of LCCs. The effect of pH on the prepared DHPKGC was investigated. The structure of the DHPKGC was characterized by Fourier Transform Infrared (FTIR), 13C-Nuclear Magnetic Resonance (13C-NMR), and two-dimensional Heteronuclear Single Quantum Coherence Nuclear Magnetic Resonance (2D HSQC NMR) analyses. The results indicated the pH of 4.0 was conducive to the polymerization reaction between DHPs and oxidized KGM by the TEMPO/NaClO/NaBr system. In addition, the resultant DHPKGC was connected by benzyl ester linkages. Overall, this study aims to gain greater insight into the process of LCC formation in plants. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, a novel bio-based polyphenol diol intermediate (VDP) was synthesized through a combination of aldimine condensation and addition reactions, utilizing vanillin, 4,4′diamino diphenylmethane (DDM), and 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO) as reactants, then various contents of VDP was introduced covalently into the polyurethane backbone. The integration of VDP has notably improved the flame retardancy of polyurethane elastomer, the limiting oxygen index (LOI) of the elastomer was elevated from 23% to 30%, and reaches V-0 rating in the UL-94 vertical burning test. The enhancement of flame retardancy is attributed to the introduction of VDP units, which not only generate PO· and PO 2 ∙ that can capture active free radicals during combustion, but also releases non-flammable gases to improve the flame-retardant effect. Moreover, the VDP enhances the decomposition activation energy values (E α) from 109.3 to 227.6 KJ/mol at mass loss rate (α) = 10%, which is attributed to the rigid benzene ring structure of VDP that significantly enhances the intermolecular interactions within the polyurethane chains. Furthermore, the elastomer shows excellent rebound resilience and reprocessability, retaining 98.6% of its original mechanical properties after multiple cycles of hot-press remolding and solvent casting. [ABSTRACT FROM AUTHOR]

Chiral tertiary alcohols are an important structural motif, however, the general and efficient methodologies for their synthesis are less reported. Herein, we report a Ni(ІІ)-catalyzed asymmetric alkenylation and arylation of aryl ketones with organoborons under air via a 1,5-metalate shift strategy to obtain chiral tertiary allylic alcohols and diaryl alcohols. The reaction demonstrates good functional group tolerance and delivers chiral tertiary alcohols with good to excellent results. Furthermore, this method can be applied to the late-stage modification of drugs and the efficient synthesis of natural products. Notably, the reaction proceeds through an outer-sphere mechanism. The Ni(II) complex functions both as a Lewis acid to activate the ketone and create a chiral environment, and as coordination bridge linking the ketone and the organoboron-derived "ate" complex, facilitating the 1,5-metalate shift without forming a C-Ni bond. This approach contrasts with traditional transition metal-catalyzed nucleophilic addition reactions that involve carbon-metal bond formation. Chiral tertiary alcohols are an important structural motif, but the general methodologies for the synthesis are less reported. Herein, the authors report a Ni(ІІ)-catalyzed asymmetric alkenylation and arylation of aryl ketones with organoborons under air via a 1,5-metalate shift to obtain chiral tertiary allylic alcohols and diaryl alcohols. [ABSTRACT FROM AUTHOR]

This review introduces the synthetic organic chemical value of α‐bromocarbonyl compounds with tertiary carbons. This α‐bromocarbonyl compound with a tertiary carbon has been used primarily only as a radical initiator in atom transfer radical polymerization (ATRP) reactions. However, with the recent development of photo‐radical reactions (around 2010), research on the use of α‐bromocarbonyl compounds as tertiary alkyl radical precursors became popular (around 2012). As more examples were reported, α‐bromocarbonyl compounds were studied not only as radicals but also for their applications in organometallic and ionic reactions. That is, α‐bromocarbonyl compounds act as nucleophiles as well as electrophiles. The carbonyl group of α‐bromocarbonyl compounds is also attractive because it allows the skeleton to be converted after the reaction, and it is being applied to total synthesis. In our survey until 2022, α‐bromocarbonyl compounds can be used to perform a full range of reactions necessary for organic synthesis, including multi‐component reactions, cross‐coupling, substitution, cyclization, rearrangement, stereospecific reactions, asymmetric reactions. α‐Bromocarbonyl compounds have created a new trend in tertiary alkylation, which until then had limited reaction patterns in organic synthesis. This review focuses on how α‐bromocarbonyl compounds can be used in synthetic organic chemistry. [ABSTRACT FROM AUTHOR]

Traditional polyamide elastomer synthesis via polycondensation of diamines and dicarboxylic acids involves high energy use and by‐product mass loss. Here, we present a novel method using thiol‐Michael addition click chemistry to produce these elastomers under mild conditions, marking the first use of this strategy. The polymerization involves coupling bis‐acrylamide (BAA) with 3,6‐dioxa‐1,8‐octanedithiol (DODT), catalyzed by 1,5‐diazabicyclo[4.3.0]non‐5‐ene (DBN). BAA is synthesized from polyetheramine and acryloyl chloride, creating a compound with amide groups and carbon double bonds at chain ends. These double bonds' electron‐withdrawing effect facilitates the click reaction efficiently, avoiding high energy and mass loss. The resulting polymers have a molecular weight of approximately 10,000 g/mol, verified by 1H NMR and FTIR spectroscopy, which show amide group presence. SAXS and AFM confirm nanophase separation of these groups. Tensile strength ranges from 0.235 to 0.542 MPa, decreasing with lower polyetheramine content but still showing notable elasticity. This method's low energy use, no mass loss, and good mechanical properties make it promising for developing high‐performance polyamide plastics and elastomers, appealing to researchers in both academia and industry. Highlights: High elasticity, softness, and high tensile polyamide elastomer.Thiol‐Michael addition click reaction conforms to atomic economy.Long molecular chain contains extraordinary evolution of hydrogen bonding. [ABSTRACT FROM AUTHOR]

Reactive melt infiltration (RMI) is a typical method to produce carbon fiber-reinforced ultra-high temperature ceramic matrix composites (C f /UHTCs), for which the molten Si is a very general and practical infiltrator. High-entropy carbide (HE-carbide) is a newly developed promising matrix phase of C f /UHTCs. Understanding the phase equilibrium relation in the HE-carbide and Si reaction system can provide accurate guidance on designing the RMI process for preparing HE-carbide matrix composites with controlled phases and microstructure. This study systematically investigates W-containing HE-carbide and Si addition reactions at high temperatures. Samples with nominal starting compositions of (Ti 0. 2 Zr 0.2 Hf 0.2 Ta 0. 2 W 0.2)C- x Si (HEC- x Si, x = 2.5, 5 and 10 wt%) are prepared by spark plasma sintering technique at 1500 °C and 1700 °C with an axial pressure of 40 MPa for 10 min. The results show that adding 2.5 wt% or 5 wt% Si removes carbon from the HEC matrix, forming SiC and stable equimolar (Ti 0. 2 Zr 0.2 Hf 0.2 Ta 0. 2 W 0.2)C 1- x phase with carbon deficiency at high temperatures. In contrast, besides the SiC phase, the addition of 10 wt% Si in the HEC matrix may form unstable transient phases of (Ti 0. 2 Zr 0.2 Hf 0.2 Ta 0. 2 W 0.2)C 1- x with supersaturated carbon deficiencies at high temperatures, which finally decomposes into non-equimolar HE-carbide (Ti 0. 2 Zr 0.2 Hf 0.2 Ta 0. 2 W 0.2- y)C 1- z and metal silicide WSi 2 phases. The effects of the HEC and Si reactions on the microstructure evolution of the samples during sintering are discussed. Meanwhile, the mechanical properties of the samples with the reaction resulting microstructure are measured and briefly discussed. [ABSTRACT FROM AUTHOR]

This article describes the synthesis of a hydrophobic protective coating for concrete based on a silane derivative of fatty acids. The coating was obtained through a thiol-ene click addition reaction using methyl oleate and 3-mercaptopropyltrimethoxysilane in the presence of the photoinitiator 2,2-dimethoxy-2-phenylacetophenone (DMPA). This reaction proved to be more efficient compared with other tested (photo)initiators, considering the double bond conversion of oleate. The coating was applied to concrete using two methods: immersion and brushing. Both methods exhibited similar consumption of methyl oleate-based silane (UVMeS) at approximately 20 g/m2. The hydrophobic properties of the coatings were evaluated based on the contact angle, which for the modified surfaces was above 93°, indicating their hydrophobic nature. The penetration depth of the silane solution into the concrete was also studied; it was 5–7 mm for the immersion method and 3–5 mm for the brushing method. The addition of tetraethoxysilane (TEOS) to the silane solution slightly improved the barrier properties of the coating. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Organic fluorides are widely used in pharmaceuticals, agrochemicals, material sciences, and other fields due to the special physical and chemical properties of fluorine atoms. The synthesis of alkyl fluorinated compounds bearing multiple contiguous stereogenic centers is the most challenging research area in synthetic chemistry and has received extensive attention from chemists. This review summarized the important research progress in the field over the past decade, including asymmetric electrophilic fluorination and the asymmetric elaboration of fluorinated substrates (such as allylic alkylation reactions, hydrofunctionalization reactions, Mannich addition reactions, Michael addition reactions, aldol addition reactions, and miscellaneous reactions), with an emphasis on synthetic methodologies, substrate scopes, and reaction mechanisms. [ABSTRACT FROM AUTHOR]

The development of highly efficient and stable visible-light-driven photocatalysts for the removal of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) from water is still a challenge. In this work, Bi2MoO6 (BMO) materials with different morphology were successfully prepared via a simple hydrothermal method by altering the solvent. The morphology of the BMO material is mainly influenced by the solvent used in the synthesis (H2O, ethanol, and ethylene glycol or their mixtures) and to a lesser extent by subsequent thermal annealing. BMO with aggregated spheres and nanoplate-like structures hydrothermally synthesized in ethylene glycol (EG) and subsequently calcined at 400 °C (BMO-400 (EG)) showed the highest adsorption capacity and photocatalytic activity compared to other synthesized morphologies. Complete degradation of 2,4-D on BMO upon irradiation with a blue light-emitting diode (LED, λmax = 467 nm) was reached within 150 min, resulting in 2,4-dichlorophenol (2,4-DCP) as the main degradation product. Holes (h+) and superoxide radicals (⋅O2−) are assumed to be the reactive species observed for the rapid conversion of 2,4-D to 2,4-DCP. The addition of H2O2 to the reaction mixture not only accelerates the degradation of 2,4-DCP but also significantly reduces the total organic carbon (TOC) content, indicating that hydroxyl radicals are crucial for the rapid mineralization of 2,4-D. Under optimal conditions, the TOC value was reduced by 84.5% within 180 min using BMO-400 (EG) and H2O2. The improved degradation performance of BMO-400 (EG) can be attributed to its particular morphology leading to lower charge transfer resistance, higher electron–hole separation, and larger specific surface area. [ABSTRACT FROM AUTHOR]

Thiophene is the organic sulfur with good thermal stability in carbon-based fuel, clarifying the conversion mechanism between thiophene and COS is beneficial for achieving in-situ sulfur fixation during CO2 gasification of carbon-based fuels, but the mechanism has rarely been reported. Therefore, calculations based on density functional theory were performed and 16 reaction paths were proposed in this research, clarifying the decomposition mechanism of thiophene and re-fixation mechanism of COS. The attachment of CO2 will lead to the destruction of the thiophene ring and the generation of COS, and CO2 adsorption is the rate-determined step, while the carbon atom that adjacent sulfur atom is the reaction active site. However, the energy barriers of CO2 addition reactions are lower than those of CO2 adsorption reactions, and the energy barrier of reactions occurring on the aliphatics are lower than that occurring on the aromatics. The combination of CO2 and thiophene will thermodynamically lead to the generation of COS and CO. Moreover, gaseous sulfur generated from thiophene decomposition will be converted mutually, while H2S will not be converted into COS. Furthermore, COS will be captured by char, forming solid organic sulfur. The re-fixation of COS will occur on aliphatic chains from the decomposition of aromatics. [ABSTRACT FROM AUTHOR]

Generation of lignin-carbohydrate complex (LCC) between dehydrogenation polymer (DHP) and pulp fibers may have an important impact on the properties of pulp. In this work, the benzyl ester-type LCC was formed between oxidized cellulose and DHP. The effect of pH on the addition reaction of oxidized cellulose to quinone methide in the synthesis of DHP-cellulose complex (DHPCC) was investigated. The structure of the product was characterized by Fourier Transform Infrared (FTIR), Carbon 13-Nuclear Magnetic Resonance (13C-NMR), and 2-Dimensional Heteronuclear Single Quantum Coherence Nuclear Magnetic Resonance (2D HSQC NMR) analyses. The results indicated that cellulose was indeed oxidized and carboxyl groups were introduced into cellulose by the oxidation process. The formed DHPCC was connected by benzyl ester linkage. In addition, the pH of the reaction system had an important role in the formation of the benzyl ester bonds. The acidic condition (pH = 4.0) was conducive to the addition reaction of quinone methide with carboxyl groups of cellulose. Overall, this study provides helpful guidance for the generation of LCC between DHP and paper pulp fibers. [ABSTRACT FROM AUTHOR]

A possibility of use of the Michael addition reaction of the A, Bring fragment enolate to sulfoxide 2(S)[(4methyl phenyl) sulfinyl]2cyclopenten1one for constructing the main skeleton of 9,11secosterols was studied. The reaction was conducted with the racemic or the enantiomerically enriched sulfoxide as the acceptor, affording a mixture of five or three main diastereomers, respectively. It was shown that the diastereoselectivity of that addition reaction is relatively low and does not afford a competitive new route for the total synthesis of secosterols. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) is a greenhouse gas, and its resource use is vital for carbon reduction and neutrality. Herein, the nucleophilic addition reaction of calcium carbide (CaC2) to CO2 was studied for the first time to synthesize propiolic and butynedioic acids by using CuI or AgNO3 as catalyst, Na2CO3 as additive, and triphenylphosphine as ligand in the presence/absence of a hydrogen donor. The effects of the experimental conditions and intensification approach on the reaction were investigated. The reactivity of CaC2 is closely associated with its synergistic activation by the catalysts, solvent, and external intensification, such as the ultrasound and mechanical force. Ultrasound helps to promote the reaction by enhancing the interfacial mass transfer of CaC2 particulates. Mechanochemistry can effectively promote the reaction, yielding 29.8% of butynedioic acid and 74.8% of propiolic acid after 2 h ball milling at 150 rpm, arising from the effective micronization and interfacial renewal of calcium carbide. The present study sheds a light on the high-value uses of CO2 and CaC2 and is of reference significance for the nucleophilic reaction of CaC2 with other carbonyl compounds. [ABSTRACT FROM AUTHOR]

Chiral mono- and bis-(thio)urea supramolecular organocatalysts were studied in the enantioselective vinylogous addition reaction of 2-trimethylsilyloxyfuran (TMSOF) to carbonylic compounds; the corresponding chiral γ-hydroxymethyl-butenolides are obtained in good yields and with high enantiomeric excesses. The catalyst structure, as well as the reaction conditions, strongly influence the efficiency of the reaction. The conformational features of mono(thio)urea catalysts 2 and 3 and bis(thio)urea catalysts 7 and 8 were investigated by DFT calculations along with the structure of their complexes with benzaldehyde. Natural Bond Orbital (NBO) and Non-Covalent Interaction (NCI) calculations provided useful information concerning the activating H-bonding interactions in the complexes. [ABSTRACT FROM AUTHOR]

This study investigated the effects of Ga doping (0.1–1 wt.% Ga) on Sn-Ga/Cu interfacial reactions. In liquid-state reactions at 250°C, the addition of 0.1 wt.% and 0.2 wt.% Ga induced the formation of scallop-shaped Cu6Sn5 and Cu3Sn phases, with ripening of Cu6Sn5 grains. However, Ga concentrations > 0.5 wt.% led to an unstable microstructure evolution. Initially, a thin layer of γ1-Cu9Ga4 formed but later detached and disintegrated in the solder, followed by Cu6Sn5 formation. Notably, Ga enhanced Cu6Sn5 nucleation, refining grains and promoting faster growth. The solid-state Sn-Ga/Cu reactions were also examined at 140°C to 200°C. Adding 0.2 wt.% Ga had no significant influence on the Cu6Sn5 and Cu3Sn formation, but the Cu3Sn/Cu6Sn5 thickness ratio increased with decreasing aging temperature, probably because of the higher Cu diffusion to Sn at lower temperatures. However, the interface with 0.5 wt.% Ga became unstable, particularly < 160°C, resulting in Cu6Sn5 dissolution, phase fracture, and Cu substrate dissolution. This instability was attributed to Cu outer-diffusion induced by Ga at lower temperatures. In contrast, the interface was relatively stable at 200°C. Similar interfacial results were observed with 1 wt.% Ga. Additionally, the phase equilibria of Sn-Ga-Cu system at 250°C were investigated to discuss the interfacial reactions. [ABSTRACT FROM AUTHOR]

The hydrochlorination of alkenes has been extensively studied in research and is commonly featured in organic chemistry textbooks as an exemplification of the Markovnikov rule. However, the application of this reaction is typically limited to specific alkenes, such as highly substituted ones, styrenes, or strained systems. Conversely, monosubstituted or 1,2-disubstituted alkenes do not readily react with HCl gas or solutions of HCl gas at practical rates. The challenges associated with hydrochlorination reactions for these "non-activated" alkenes have spurred considerable research efforts over the past 30 years, which constitute the primary focus of this review. The discussion begins with classical polar hydrochlorinations, followed by metal-promoted radical hydrochlorinations, and concludes with a brief overview of recent anti-Markovnikov hydrochlorinations.

The collective total syntheses of (±)‐hosieines A–C with a cage‐like tetracyclic framework have been realized, which includes the first syntheses of hosieines B‐C. The key strategy of the synthesis employs a one‐pot domino reaction that involves Cu‐catalyzed [3+2] cycloaddition, 1,6‐enone formation, and 1,6‐aza‐Michael addition forming the 5/6/6‐aza‐tricyclic skeleton. Other salient synthetic tactics comprise a challenging double bond migration and a 1,4‐aza‐Michael addition reaction to afford the tetracyclic framework. [ABSTRACT FROM AUTHOR]

Podophyllotoxin, a cyclolignan natural product, has been the object of extensive chemomodulation to obtain better chemotherapeutic agents. Among the obtained podophyllotoxin derivatives, podophyllic aldehyde showed very interesting potency and selectivity against several tumoral cell lines, so it became our lead compound for further modifications, as described in this work, oriented toward the enlargement of the cyclolignan skeleton. Thus, modifications performed at the aldehyde function included nucleophilic addition reactions and the incorporation of the aldehyde carbon into several five-membered rings, such as thiazolidinones and benzo-fused azoles. The synthesized derivatives were evaluated against several types of cancer cells, and although some compounds were cytotoxic at the nanomolar range, most of them were less potent and less selective than the parent compound podophyllic aldehyde, with the most potent being those having the lactone ring of podophyllotoxin. In silico ADME evaluation predicted good druggability for most of them. The results indicate that the γ-lactone ring is important for potency, while the α,β-unsaturated aldehyde is necessary to induce selectivity in these cyclolignans. [ABSTRACT FROM AUTHOR]

Some of triazole derivatives are synthesized by cyclization reaction of thiocarbohydrazide synthesized by reaction of carbon disulphide and aqueous hydrazine; the basic nucleus 3-methyl-4-amino-1,2,4-triazole-5-thione (L) is prepared by reaction of thiocarbohydrazide compound with glacial acetic acid under reflux condition. The compound (L) is subjected to addition reaction with different aldehydes to synthesize Schiff bases 1,3[N,N-Bis(5-methyl-1,3,4- triazole-2-thione)] benzene (L1) and 1,4[N,N-Bis(5-methyl-1,3,4-triazole-2- thione)] benzene (L2). The compounds (L1) and (L2) are confirmed by means of their melting point, FTIR, UV-visible, and ¹H-NMR spectra. [ABSTRACT FROM AUTHOR]

The transient electron donor–acceptor (EDA) complex has been an emerging area in the photoinduced organic synthesis field, generating radicals without exogenous transition‐metal or organic dye‐based photoredox catalysts. The catalytic platform to form suitable photoactive EDA complexes for photochemical reduction reactions remains underdeveloped. Herein, a general photoinduced reductive alkylation via the EDA complex strategy is described. A simple yet multifunctional system, triphenylphosphine and iodide salt, promotes the photoinduced decarboxylative hydroalkylation, and reductive defluorinative decarboxylative alkylation of trifluoromethyl alkenes, to access trifluoromethyl alkanes and gem‐difluoroalkenes. Moreover, decarboxylative hydroalkylation can be applied to more kinds of electron‐deficient alkenes as a general Giese addition reaction. [ABSTRACT FROM AUTHOR]

An enantioselective addition reaction for the construction of 1,3‐nonadjacent stereogenic centers is developed by means of a chiral strong Brønsted base catalyst. The chiral sodium ureate catalyst efficiently promoted the reaction of α‐thioacetamides as less acidic pronucleophiles with vinyl sulfones having a variety of α‐substituents including aryl, alkyl and halo groups, and α‐phenylacrylates, accomplishing the construction of various 1,3‐nonadjacent stereogenic centers in highly diastereo‐ and enantioselective manners. This is a rare example of the construction of 1,3‐nonadjacent stereogenic centers with less acidic pronucleophiles. In addition, the application of Michael acceptors having various types of α‐substituents in a single catalyst system is achieved for the first time, demonstrating the utility of the present catalyst system for the construction of 1,3‐nonadjacent stereogenic centers. [ABSTRACT FROM AUTHOR]

The aqueous-phase chemistry of glyoxal (GL) with reduced nitrogen compounds (RNCs) is a significant source for secondary brown carbon (SBrC), which is one of the largest uncertainties in climate predictions. However, a few studies have revealed that SBrC formation is affected by multifunctional RNCs, which have a non-negligible atmospheric abundance. Hence, we assessed theoretical and experimental approaches to investigate the reaction mechanisms and kinetics of the mixtures for ammonium sulfate (AS), multifunctional amine monoethanolamine (MEA), and GL. Our experiments indicate that light absorption and growth rate are enhanced more efficiently in the MEA–GL mixture relative to AS–GL and MEA–AS–GL mixtures and MEA reactions of the chromophores than in the analogous AS reactions. Quantum chemical calculations show that the formation and propagation of oligomers proceed via four-step nucleophilic addition reactions in three reaction systems. The presence of MEA provides the two extra branched chains that affect the natural charges and steric hindrance of intermediates, facilitating the formation of chromophores. Molecule dynamics simulations reveal that the interfacial and interior attraction on the aqueous aerosols with MEA is more pronounced for small α -dicarbonyls to facilitate further engagement in the aqueous-phase reactions. Our results show a possible missing source for SBrC formation on urban, regional, and global scales. [ABSTRACT FROM AUTHOR]

RECENT ADVANCES IN THE ELECTROPHILIC ADDITION OF CHALCOGEN ATOMS TO ALKENES. Organochalcogen compounds (containing S, Se and Te) are interesting from biological point of view, but also in their use as intermediates in obtaining complex molecules or even for exploring their properties. In this way, chalcogen electrophiles are very powerful reactants and can be added to alkenes to form a three-membered intermediate called chalcogeniranium ion. This specie reacts with different nucleophiles to undergo a series of molecules containing chalcogens with interesting properties. The addition of electrophiles from chalcogens to alkenes is one of the oldest reactions in the field of the chemistry of these compounds and because of this many modifications have already been explored. Among them, methodologies that make use of transition metals to the most recent ones exploring aspects of Green Chemistry. This review starts with an overview of the background involved in electrophilic addition reactions of organochalcogenic compounds in alkenes and then, describes the recent methodologies leading to the synthesis of useful molecules and hoping that it will be beneficial to provoke further research and reflection in this field.

We disclose herein a strategy for the rapid synthesis of versatile organoselenium compounds under mild conditions. In this work, magnesium-based selenium nucleophiles are formed in situ from easily available organic halides, magnesium metal, and elemental selenium via mechanical stimulation. This process occurs under liquid-assisted grinding (LAG) conditions, requires no complicated pre-activation procedures, and operates broadly across a diverse range of aryl, heteroaryl, and alkyl substrates. In this work, symmetrical diselenides are efficiently obtained after work-up in the air, while one-pot nucleophilic addition reactions with various electrophiles allow the comprehensive synthesis of unsymmetrical monoselenides with high functional group tolerance. Notably, the method is applied to regioselective selenylation reactions of diiodoarenes and polyaromatic aryl halides that are difficult to operate via solution approaches. Besides selenium, elemental sulfur and tellurium are also competent in this process, which showcases the potential of the methodology for the facile synthesis of organochalcogen compounds. While the reported methods for the synthesis of organoselenium compounds mainly employ preformed activated selenium reagents, the direct utilization of elemental selenium in the synthesis is a more attractive but challenging strategy. Here, the authors report the rapid synthesis of versatile organoselenium compounds via mechanical stimulation. [ABSTRACT FROM AUTHOR]

Vinyldiazo compounds are one of the most important synthons in the construction of a cyclic ring. Most photochemical transformations of vinyldiazo compounds are mainly focusing on utilization of their C═C bond site, while reactions taking place at terminal nitrogen atom are largely unexplored. Herein, a photocatalytic cascade radical cyclization of LBRs with vinyldiazo reagents through sequential B─N/C─N bond formation is described. The reaction starts with the addition of LBRs (Lewis base–boryl radicals) at diazo site, followed by intramolecular radical cyclization to access a wide range of important boron‐handled pyrazoles in good to excellent yields. Control experiments, together with detailed mechanism studies well explain the observed reactivity. Further studies demonstrate the utility of this approach for applications in pharmaceutical and agrochemical research. [ABSTRACT FROM AUTHOR]

This review focuses on the reactivity of cyclopropenes in addition reactions of carbon- or heteroatomcentered radicals, generated through classical initiating systems or photocatalysis. These addition reactions lead to cyclopropyl radicals as intermediates which can undergo subsequent atom transfer (inter- or intramolecular) or be involved in cyclization reactions. In some cases, depending on the structure of the added radical, the cyclopropyl radical intermediate can evolve by ring-opening and elimination reactions leading to open-chain unsaturated products or heterocyclic compounds. This review discusses the contributions that have been made in this field and highlights the scope and mechanisms of the different transformations. [ABSTRACT FROM AUTHOR]

This article provides a method to upgrade epoxy-functionalized carriers for covalent enzyme immobilization to selective carriers suitable for covalent immobilization of metal affinity-tagged enzymes without the need of preliminary enzyme purification. Affinity function doping of the epoxy-functionalized surface introduces an advanced possibility to avoid the costly and time-consuming downstream processes required for efficient immobilization on non-selective epoxy carriers. Our approach is based on the partial functionalization of surface epoxides via a proper diamine-derived linker and an ethylenediaminetetraacetic dianhydride-based chelator charged with cobalt ions. The solid macroporous carriers, doped with metal affinity functions, have both coordinative binding ability (rapid anchoring the metal affinity-tagged enzymes to the surface) and subsequent covalent bond-forming ability (preferred binding of the tagged enzyme to the surface after proper washing by the residual epoxide functions), enabling a single operation for the enrichment and immobilization of a recombinant phenylalanine ammonia-lyase from parsley fused to a polyhistidine affinity tag. The immobilized PcPAL was applied in the ammonia elimination of racemic phenylalanine, 4-chlorophenylalanine, and 4-bromophenylalanine to produce the corresponding d-phenylalanines, in addition to the formation of (E)-cinnamates, as well as in ammonia addition reactions to (E)-cinnamates, yielding the corresponding enantiopure l-phenylalanines. [ABSTRACT FROM AUTHOR]

Dehydration is an abundant and promising process in chemical, biochemical, and industrial fields. Dehydration methods can contribute to building a modern and sustainable society with minimal environmental impact. Breakthrough advances in the dehydrative SN1 reaction can be achieved through the discovery of new cationic indium catalysts. Here we show that the breakthrough advances in the dehydrative SN1 reaction can be achieved using the cationic indium catalysts. The dehydrative carbon–carbon bond formation of α-alkyl propargyl alcohols afforded a wide variety of α-aryl- and heteroaryl-propargyl compounds. Mechanistic investigations into this process revealed that the InCl3/AgClO4/Bu4NPF6/1,1'-binaphthol catalytic system generated a powerful cationic indium catalyst that could promote the dehydration of alcohols. Labile α-alkyl propargyl cations were found to self-condense, and the catalyst system efficiently regenerated propargyl cations for reaction with nucleophiles. This propargylation reaction directly proceeded from the corresponding alcohols under mild and open-air conditions and tolerated a broad scope of functional groups. Furthermore, a wide variety of nucleophiles, including aromatic and heteroaromatic compounds, phenols, alcohols, and sulfonamides, reacted with the corresponding cations to afford the propargyl compounds in good to high yields. Finally, the synthetic utility of this reaction was demonstrated by the synthesis of colchicine and allocolchicine analogues. The dehydration process could help create new compounds that were previously impossible to synthesize and is more eco-friendly and efficient than conventional methods. Nucleophilic addition reactions of propargyl cations can result in diverse synthetically useful compounds, however, dehydrative propargylation through α-alkyl-propargyl cations remains challenging. Here, the authors utilize a highly oxophilic indium cation to generate α-alkyl-propargyl cations from secondary alcohols and apply them to SN1-propargylation. [ABSTRACT FROM AUTHOR]

Thia-Michael addition reactions are significant for organic syntheses of important class of compounds to form C-S bond and its derivatives. It shows the prominent feature in medicinal field and material science. This review is focused on various methods towards thia-Michael adducts using Michael addition of sulfur containing electron rich species (Michael donor) on electron poor olefins (Michael acceptor). The C-S bond is ideal of making bioactive molecules generalized for the synthesis of various drug molecules and applied in field as insect sprays and polymer substances which are common for daily life. Due to the importance of C-S bond in recent years, novel methods for C-S bond formation were developed, which are more convenient with environment. [ABSTRACT FROM AUTHOR]

Developing a novel methodology for the synthesis of functionalized polysiloxanes is highly desirable because of their extensive applications in engineering, textile, construction, electronics, and medical systems. Herein we introduce the oxa-Michael addition reaction as an efficient methodology to prepare a series of functionalized polysiloxanes from hydroxyalkyl-containing polysiloxanes and vinyl monomers using phosphazene base as the catalyst. The effects of various factors, including reaction time, feed ratio and solvent, were explored in this reaction. It was found that the reaction can be carried out under mild reaction (room temperature in 6 h to 24 h) with moderate to high conversion yields (60% to 99%). In particular, vinyl monomers with strong electron-withdrawing groups (e.g., cyano and sulfone groups) have higher reactivity, and the functionalized polysiloxanes can be obtained quantitatively or near-quantitatively. Interestingly, their molecular weights determined by gel permeation chromatography (GPC) reveal that the Si-O-Si skeletons were attacked by phosphazene base and re-arranged during the reaction, thus leading to improved molecular weights and more uniform molecular weight distributions in the final products than the original polysiloxanes. Moreover, these polysiloxanes exhibited intriguing nonconventional fluorescence due to the presence of unique chromophores, and those containing cyano and sulfone groups particularly exhibit the best fluorescence performance. More organosilicon materials could be developed under this simple strategy. [ABSTRACT FROM AUTHOR]

Hydrogel has been widely used in reservoir regulation for enhancing oil recovery, however, this process can experience negative influences on the properties and effects of the hydrogels. Therefore, developing novel hydrogels with excellent environmental responsiveness would improve the formation adaptability of hydrogels. In this study, novel polyvinyl polyamine hydrogels were synthesized by a ring-opening addition reaction between polyvinyl polyamines and polyethylene glycol glycidyl ether. The results of atomic force microscopy and transmission electron microscopy showed that the polyvinyl polyamine gel had a porous and irregular bulk structure and was endowed with water storage. With the temperature rising from 30 °C to 60 °C, the transmittance of diethylenetriamine hydrogel decreased from 84.3% to 18.8%, indicating that a phase transition had occurred. After the polyvinyl polyamine hydrogel with low initial viscosity was injected into the formation in the liquid phase, the increase of the reservoir temperature caused it to turn into an elastomer, thereby migrating to the depth of the reservoir and achieving effective plugging. Polyvinyl polyamine hydrogel could improve the profile of heterogeneous layers significantly by forcing subsequent fluids into the low permeability zone in the form of elastomers in the medium temperature reservoirs of 40–60 °C. The novel environmentally responsive polyvinyl polyamine hydrogels, capable of phase transformation with temperature, exhibited superior performance in recovering residual oil, which was beneficial for applications in reservoir profile control and oilfield development. [ABSTRACT FROM AUTHOR]

In this work, new partially substituted derivatives of octa(3-thiopropyl)silsesquioxane (SSQ-8SH) were synthesized. The article compares the thiol-ene reaction using two methods: radical mechanism, thermally initiated (AIBN), and in the presence of a photoinitiator (DMPA). Both the crystalline and the oil forms of SSQ-8SH were functionalized. Olefins with nonpolar alkyl groups (hexene, octene, and octadecene) and vinyltrimethoxysilane, allyl glycidyl ether, allyl 2,2,3,3,4,4,5,5-octafluoropentylether, allyl methacrylate, and styrene were used in the reactions, allowing to obtain seven new derivatives. All compounds were characterized using spectroscopic (1H NMR and 29Si NMR) and spectrometric (MALDI-TOF-MS) methods. The influence of functional groups on the water contact angle value was determined. The functionalization of the compound led to a contact angle value above 95° (SSQ-4SH-4OD). Density measurements and thermogravimetric analysis (TGA) were carried out for all compounds. The highest onset temperature (357.4 °C) and temperature at the maximum mass loss rate (377.3 °C) were observed for SSQ-SH-4OD. The addition of alkyl groups significantly decreased the density of compounds with increasing chain length (1.198 g/cm3; 1.162 g/cm3; 1.095 g/cm3 for hexene, octene, and octadecene, respectively). Silsesquioxanes have potential applications in various materials, such as UV-curable resins, allowing to modify, for example, their surface properties. Modification of a commercial photocurable resin with selected derivatives was carried out to determine the impact on physicochemical properties (TGA, WCA). [ABSTRACT FROM AUTHOR]

The N-functionalized indole is a privileged structural framework in a wide range of bioactive molecules. The nucleophilic addition between indoles with vinylene carbonate proceeded smoothly in the presence of K2CO3 as the catalyst to produce novel indolyl-containing skeletons and 4-indolyl-1,3-dioxolanones in satisfactory to excellent yields (up to >97% yield). Various synthetically useful functional groups, such as halogen atoms, cyano, nitro, and methoxycarbonyl groups, remained intact during the regioselective N-H addition reactions. The developed catalytic system also could accommodate 2-naphthalenol to achieve the target O-H additive product in good yield. [ABSTRACT FROM AUTHOR]

The Localized Surface Plasmon (LSP) effect of 5 nm mean size Au particles deposited on TiO2 P25 was investigated during the photo-thermal water gas shift reaction (WGSR). The effects of CO concentration, excitation light flux and energy, and molecular oxygen addition during the reaction were investigated. The photocatalytic WGSR rate under light excitation with wavelengths extending from 320 to 1100 nm was found to be higher than the thermal reaction alone at the same temperature (85 °C). A H2/CO2 ratio of near unity was found at high concentrations of CO. The addition of molecular oxygen during the reaction resulted in a slight decrease in molecular hydrogen production, while the rates of CO2 formation and CO consumption changed by one order of magnitude. More importantly, it was found that the WGSR rates were still high under only visible light excitation (600–700 nm). The results prove that Au LSP alone triggers this chemical reaction without requiring the excitation of the semiconductor on which they are deposited. [ABSTRACT FROM AUTHOR]

A mononuclear square-planar CuII complex of (5-methyl-1H-pyrazol-3-yl) carbamate, [Cu(C5H6N3O2)2]⋅4H2O, was synthesized using a one-pot reaction from 5-methyl-3-pyrazolamine and copper(II) acetate in water under ambient conditions. The adsorption of carbon dioxide from air was facilitated by the addition of diethanolamine to the reaction mixture. While diethanolamine is not a component of the final product, it plays a pivotal role in the reaction by creating an alkaline environment, thereby enabling the adsorption of atmospheric carbon dioxide. The central copper(II) atom is in an (N2O2) squareplanar coordination environment formed by two N atoms and two O atoms of two equivalent (5-methyl-1H-pyrazol-3-yl)carbamate ligands. Additionally, there are co-crystallized water molecules within the crystal structure of this compound. These co-crystallized water molecules are linked to the CuII mononuclear complex by O--H⋯O hydrogen bonds. According to Hirshfeld surface analysis, the most frequently observed weak intermolecular interactions are H⋯O/O⋯H (33.6%), H⋯C/C⋯H (11.3%) and H⋯N/N⋯H (9.0%) contacts. [ABSTRACT FROM AUTHOR]

As an important cancer therapeutic target, extracellular signal-regulated kinases (ERK) are involved in triggering various cellular responses in tumors. Regulation of the ERK signaling pathway by the small molecular inhibitors is highly desired for the sake of cancer therapy. In contrast to the routine inhibitors targeting ERKs through long-range non-bonding interactions, Ponatinib, a covalent inhibitor to ERK2 with a macrocyclic structure characterized by the α,β-C=C unsaturated ketone, can form the stable -C(S)-C(H)-type complex via the four-center barrier due to the nucleophilic addition reaction of the thiol group of the Cys166 residue of ERK2 with the C=C double bond of Ponatinib with reaction free-energy barrier of 47.2 kcal/mol. Reaction mechanisms for the covalent binding were calculated using QM/MM methods and molecular dynamics simulations. The interaction modes and the corresponding binding free energies were obtained for the non-covalent and covalent complexation. The binding free energies of the non-covalent and covalent inhibitions are 14.8 kcal/mol and 33.4 kcal/mol, respectively. The mechanistic study stimulated a rational design on the modified Ponatinib structure by substituting the C=C bond with the C=N bond. It was demonstrated that the new compound exhibits better inhibition activity toward ERK2 in term of both thermodynamic and kinetic aspects through the covalent binding with a lower reaction free-energy barrier of 23.1 kcal/mol. The present theoretical work sheds new light on the development of the covalent inhibitors for the regulation of ERKs. [ABSTRACT FROM AUTHOR]

Interest in connecting Chemical Reactions Network Theory (CRNT) and evolutionary game theory (EGT) arise viewing the tools of network in the analysis of evolutionary games. Here, the evolution of population species is studied as a biological phenomenon and describing the rate of such changes through a replicator system becomes a focus. A set of polynomial kinetics (POK) may then be introduced for the realization of this replicator system and this is based on the polynomial payoff functions defined in the game. These polynomial kinetics result in polynomial dynamical systems of ordinary differential equations, which are used in analyzing strategies that prove beneficial under certain conditions. From the CRNT point of view, it now becomes interesting to study a superset of POK, which we call poly-PL kinetics (PYK). This set is formed by getting nonnegative linear combinations of power law functions. Thus, PYK contains the set PLK of power law kinetics as mono-PL kinetics with coefficient 1. Seeing this connection between CRNT and EGT and what are known about power law kinetics, we take an interest in studying PYK systems. This paper aims to analyze different ways of transforming PYK to PLK in order to explore some approaches for CRNT analysis of PYK systems. Specifically, we study a network structure-oriented transformations using the S-invariant term-wise addition of reactions (STAR) Via Reaction Vector Multiples (RVM) that transform PYK to PLK systems. [ABSTRACT FROM AUTHOR]

Due to the enhancement of people's environmental awareness, flame-retardant epoxy resin (EP) tends to be non-toxic, efficient, and multi-functional, and its development is systematic. At present, many new flame retardants or intrinsic modification methods reported in studies can effectively improve the flame retardability and thermal stability of EP. However, many aspects still need to be further improved. In this review, the flame-retardant mechanism and method of flame-retardant epoxy resins are briefly analyzed. The research progress of the flame-retardant modification of epoxy resin by physical addition and chemical reaction is summarized and discussed. Furthermore, the research trend of flame-retardant epoxy resin in the field of fire-protective coatings is discussed, and future problems in this field are put forward. This work may provide some new insights for the design of multi-functional integrated epoxy resin fireproof coatings. [ABSTRACT FROM AUTHOR]

The importance of organoselenium compounds has been increasing in synthetic chemistry. These reagents are well-known as electrophiles and nucleophiles in many organic transformations, and in recent years, their functionality as catalysts has also been largely explored. The interest in organoselenium-based catalysts is due to their high efficacy, mild reaction conditions, strong functional compatibility, and great selectivity. Allied to organoselenium catalysts, the use of inorganic and organic oxidants that act by regenerating the catalytic species for the reaction pathway is common. Here, we provide a comprehensive review of the last five years of organic transformations promoted by diorganyl diselenide as a selenium-based catalyst. This report is divided into four sections: (1) cyclisation reactions, (2) addition reactions and oxidative functionalisation, (3) oxidation and reduction reactions, and (4) reactions involving phosphorus-containing starting materials. [ABSTRACT FROM AUTHOR]

Monoamine oxidase (MAO, EC 1.4.3.4) is responsible for the oxidative breakdown of both endogenous and exogenous amines and exists in MAO-A and MAO-B isomers. Eighteen indole-based phenylallylidene derivatives were synthesized via nucleophilic addition reactions comprising three sub-series, IHC, IHMC, and IHNC, and were developed and examined for their ability to inhibit MAO. Among them, compound IHC3 showed a strong MAO-B inhibitory effect with an IC50 (half-maximal inhibitory concentration) value of 1.672 μM, followed by IHC2 (IC50 = 16.934 μM). Additionally, IHC3 showed the highest selectivity index (SI) value of >23.92. The effectiveness of IHC3 was lower than the reference pargyline (0.14 μM); however, the SI value was higher than pargyline (17.16). Structurally, the IHC (-H in the B-ring) sub-series exhibited relatively stronger MAO-B inhibition than the others. In the IHC series, IHC3 (-F in the A-ring) exhibited stronger MAO-B suppression than the other substituted derivatives in the order -F > -Br > -Cl > -OCH3, -CH3, and -H at the 2-position in the A-ring. In the reversibility and enzyme kinetics experiments, IHC3 was a reversible inhibitor with a Ki value of 0.51 ± 0.15 μM for MAO-B. Further, it was observed that IHC3 greatly decreased the cell death caused by rotenone in SH-SY5Y neuroblastoma cells. A molecular docking study of the lead molecule was also performed to determine hypothetical interactions in the enzyme-binding cavity. These findings suggest that IHC3 is a strong, specific, and reversible MAO-B inhibitor that can be used to treat neurological diseases. [ABSTRACT FROM AUTHOR]

Organophosphorus chemicals are versatile and important in industry. Trivinylphosphine oxide (TVPO), for example, exhibited a promising precursor as a flame-retardant additive for industrial applications. Density functional theory (DFT) simulations were used to explore the kinetic and thermodynamic chemical processes underlying the nucleophilic addition reactions of TVPO in order to better understand their polymerization mechanisms. An experimental X-ray single-crystal study of TVPO supported this work's theory based on its computed findings. TVPO was prepared using POCl3 and VMB in a temperature-dependent reaction. TVPO, the thermodynamically favourable product, is preferentially produced at low temperatures. The endothermic anionic addition polymerization reaction between TVPO and VMB begins when the reaction temperature rises. An implicit solvation model simulated TVPO and piperazine reactions in water, whereas a hybrid model modelled VMB interactions in tetrahydrofuran. The simulations showed a pseudo-Michael addition reaction mechanism with a four-membered ring transition state. The Michael addition reaction is analogous to this process. [ABSTRACT FROM AUTHOR]

In vitro compartmentalization (IVC) is a technique for generating water-in-oil microdroplets to establish the genotype (DNA information)–phenotype (biomolecule function) linkage required by many biological applications. Recently, fluorinated oils have become more widely used for making microdroplets due to their better biocompatibility. However, it is difficult to perform multi-step reactions requiring the addition of reagents in water-in-fluorinated-oil microdroplets. On-chip droplet manipulation is usually used for such purposes, but it may encounter some technical issues such as low throughput or time delay of reagent delivery into different microdroplets. Hence, to overcome the above issues, we demonstrated a nanodroplet-based approach for the delivery of copper ions and middle-sized peptide molecules (human p53 peptide, 2 kDa). We confirmed the ion delivery by microscopic inspection of crystal formation inside the microdroplet, and confirmed the peptide delivery using a fluorescent immunosensor. We believe that this nanodroplet-based delivery method is a promising approach to achieving precise control for a broad range of fluorocarbon IVC-based biological applications, including molecular evolution, cell factory engineering, digital nucleic acid detection, or drug screening. [ABSTRACT FROM AUTHOR]