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A diaminomethylenemalononitrile organocatalyst efficiently promoted asymmetric cascade Michael/Michael reactions between a 2‐(trifluoromethylmethylene)indane‐1,3‐dione derivative and α‐alkylidene succinimides, resulting in spiroindane‐1,3‐dione derivatives. These derivatives feature four consecutive carbon stereocenters, including one stereocenter with a trifluoromethyl substituent, and were formed in high yield with excellent enantioselectivity (up to 94 % ee). This study marks the first successful example of using methyleneindane‐1,3‐dione derivatives, bearing alkoxycarbonyl and trifluoromethyl groups at the β‐position, as Michael acceptors. [ABSTRACT FROM AUTHOR]

A facile and highly efficient protocol has been developed for the synthesis of extensively functionalized, fully substituted N‐methyl‐1,4‐dihydropyridines. This approach is a one‐pot pseudo‐three‐constituent cyclo‐condensation of aromatic aldehydes with (E)‐N‐methyl‐1‐(methylthio)‐2‐nitroethenamine (NMSM). This reaction presumably entails the Knoevenagel reaction followed by Michael addition and regioselective N‐cyclization with removing methanethiol and producing two C─C bonds and one C─N bond. The key advantages of this strategy include an optimized reaction time, achieving moderate to excellent yields, a straightforward experimental procedure, and the use of the ionic liquid 1‐ethyl‐3‐methylimidazolium acetate [(EMIM)Ac] as the catalyst. The resulting derivatives were well characterized by IR, 1H NMR, 13C NMR, and HRMS. [ABSTRACT FROM AUTHOR]

The present article describes the successful performance of crossed aldol reactions of the CF3-containing pseudo-C2 symmetric cyclic imide with various aldehydes. The utilization of HMPA as an additive attained the preferential formation of the anti-products in good to excellent yields, which contrasts with our previous method without this additive, proceeding to furnish the corresponding syn-isomers. The effective participation of ketones and α,β-unsaturated carbonyl compounds in reactions with this imide was also demonstrated to expand the application of this imide. [ABSTRACT FROM AUTHOR]

Highlights Poly(p‐phenylene terephthamide) (PPTA) is an aromatic para‐polyamide with a rigid rod‐like main chain and superior intrinsic mechanical properties but is insoluble in all organic solvents. It has been demonstrated that introducing amino groups to the phenyl rings on the PPTA main chain yields organic‐soluble aminated para‐polyamide known as poly(p‐aminophenylene aminoterephthalamide) ((NH2)2‐PPTA). In this study, an organic‐soluble bismaleimide (BMI)‐grafted (NH2)2‐PPTA (BMI‐g‐(NH2)2‐PPTA) was synthesized by reacting the amino groups of (NH2)2‐PPTA with the double bonds of BMI via Michael addition reaction. BMI‐g‐(NH2)2‐PPTA was then employed as a new macromolecular reinforcing agent that significantly enhances the mechanical properties of BMI/2,2′‐diallyl bisphenol A (BD) resin. With the addition of merely 0.5 wt% of BMI‐g‐(NH2)2‐PPTA, the strength and toughness of both BD resin and BD/carbon fiber (CF) composite laminates are significantly improved without decreasing the heat resistance of the matrix. The uniform dispersion of BMI‐g‐(NH2)2‐PPTA in BD resin and its strong interaction with the matrix result in a more significant enhancement in the mechanical properties compared to directly incorporating (NH2)2‐PPTA into the matrix, providing a new and efficient method for enhancing the mechanical properties of BD resin and its CF composites. A novel BMI‐grafted aminated para‐polyamide, BMI‐g‐(NH2)2‐PPTA, is synthesized. BMI‐g‐(NH2)2‐PPTA is organic‐soluble and can disperse uniformly in BD resin. BMI‐g‐(NH2)2‐PPTA at 0.5 wt% enhances the strength of BD resin by 50.8%. BMI‐g‐(NH2)2‐PPTA is more efficient than (NH2)2‐PPTA in strengthening BD resin. Mechanical properties of BD/CF laminates are also enhanced by BMI‐g‐(NH2)2‐PPTA. [ABSTRACT FROM AUTHOR]

[Display omitted] • A portable assay kit for plant volatile (E) -2-hexenal, based on luminescent gold nanoclusters hydrogel, is proposed for the first time. • Michael addition reaction and etching ability of cysteine ensure anti-interference capacity. • The portable hydrogel kit demonstrates the potential for early identification of late blight in potato plants. Plants exhibit rapid responses to biotic and abiotic stresses by releasing a range of volatile organic compounds (VOCs). Monitoring changes in these VOCs holds the potential for the early detection of plant diseases. This study proposes a method for identifying late blight in potatoes based on the detection of (E) -2-hexenal, one of the major VOC markers released during plant infection by Phytophthora infestans. By combining the Michael addition reaction with cysteine-mediated etching of aggregation-induced emission gold nanoclusters (Au NCs), we have developed a portable hydrogel kit for on-site detection of (E) -2-hexenal. The Michael addition reaction between (E) -2-hexenal and cysteine effectively alleviates the etching of cysteine-mediated Au NCs, leading to a distinct fluorescence color change in the Au NCs, enabling a detection limit of 0.61 ppm. Utilizing the superior loading and diffusion characteristics of the three-dimensional structure of agarose hydrogel, our sensor demonstrated exceptional performance in terms of sensitivity, selectivity, reaction time, and ease of use. Moreover, quantitative measurement of (E) -2-hexenal was made easier by using ImageJ software to transform fluorescent images from the hydrogel kit into digital data. Such method was effectively used for the early detection of potato late blight. This study presents a low-cost, portable fluorescent analytical tool, offering a new avenue for on-site detection of plant diseases. [ABSTRACT FROM AUTHOR]

The asymmetric Michael addition reaction of guaiazulene to α,β-unsaturated 2-acyl imidazoles was developed with a chiral-at-metal Rh(III) complex as the catalyst for the first time. The corresponding adducts were obtained in good yields (76–98%) with excellent enantioselectivities (up to 99%). The reaction could be conducted on a gram-scale with a low catalyst loading (0.05 mol%) without impacting its efficiency. DFT studies rationalize the enantioselectivity of the reaction. [ABSTRACT FROM AUTHOR]

The γ‐lactam ring is a prominent feature in medicinal chemistry, and its synthesis has garnered significant interest due to its valuable properties. Among the γ‐lactams, 2‐oxopyrrolidine‐3‐carbonitrile derivatives stand out as versatile synthons that can be readily transformed into a variety of other functional groups. In this work, we successfully synthesized highly functionalized 3‐cyano‐2‐pyrrolidinones with moderate to good overall yields using the Ugi reaction followed by intramolecular Michael addition. The process demonstrated excellent diastereoselectivity and showed good tolerance to a range of isonitriles and carbonyl compounds. [ABSTRACT FROM AUTHOR]

Here we report a transition metal– and oxidant–free annulation cascade method for the synthesis of chromeno–isoxazoles. The annulation reaction involves easily accessible starting materials, 3‐nitro‐2H‐chromene and α‐chloro aldehyde, yielding the structurally intriguing framework, chromeno[3,4‐c]isoxazoles employed by tripotassium phosphate as a base. The isoxazole ring construction over the 2H–chromene unit is believed to occur via a series of multiple reaction sequences. Here, the enolate generation/Michael addition/C−Cl bond cleavage/oxy–anionic addition to reactive tethered‐aldehyde/deformylation via retro–C−C and N−O bond cleavages are the most possible sequences which furnish the desired end–product in good chemical yields. The multiple reaction sequences occur in one‐pot at mild conditions, supported by experimental results and a few control experiments including DFT studies. This process exhibits a broad substrates scope illustrating good functional group compatibility towards both the nitrochromenes and aldehydes, and thus prove to be a general and efficient protocol for the synthesis of chromeno[3,4–c]isoxazoles. Overall, the use of nitrochromene as the limiting reagent, noteworthy functional group tolerance, scalability including great applications like chiral pool strategy towards the synthesis of enantioenriched chromeno‐isoxazole are the additional features. [ABSTRACT FROM AUTHOR]

Fluorine‐containing compounds are important in medicine or crop‐protection. Herein, we show asymmetric organocatalytic Michael/oxa‐Michael cascade leading to chiral fluorinated pyrans under mechanochemical conditions. Formal oxa‐Diels‐Alder reaction between fluorine containing unsaturated keto esters and β,γ‐unsaturated ketones afforded a range of drug‐like pyran derivatives in short times and good to high yields. Ball‐milling conveys the reaction in short times and high product yields, while keeping high enantiomeric purities of products. The reaction is diastereodivergent depending on the use of either monofunctional amine catalysts or bifunctional thiourea or squaramide. [ABSTRACT FROM AUTHOR]

Developing new enzyme‐immobilization systems to stabilize their dynamic structures and meanwhile enhance their catalytic activity is of great significance but very challenging. Herein, we design and fabricate a class of robust mesoporous covalent organic frameworks (COFs) via Michael addition‐elimination reaction. It is found that highly crystalline COFs can be produced in 10 min, which is attributed to the promoting effect of the intramolecular hydrogen bond activation. The COFs rich in hydroxyl groups can be facilely post‐modified by epibromohydrin to covalently immobilize enzymes with both high loading and activity. Furthermore, we create a solar‐driven photothermal‐promoted strategy by introducing photoactive azo groups to COF carriers, which can boost the enzyme catalytic performance (lipase) with much higher conversion of various racemic substrates and chiral resolution upon solar light irradiation. The heterogeneous biocatalysts also demonstrate exceptional reusability and stability. This work provides a green and energy‐efficient approach to facilitate the scale application of enzyme‐immobilized biocatalysts. [ABSTRACT FROM AUTHOR]

Tertiary phosphines have been recognized as powerful organocatalysts for the Michael reaction, which is one of the most important atom-economical methods for carbon-carbon and carbon-heteroatom bond construction. In the presence of tertiary phosphines, a vast array of Michael acceptors and Michael donors can be coupled with each other under neutral and metal-free conditions to produce useful densely functionalized molecules. This review highlights the role of phosphine-catalyzed Michael reaction in cutting-edge areas, such as asymmetric synthesis, natural products synthesis, drug design, and polymer material science. As the central part of catalysis science, the kinetic and mechanistic issues are also discussed when possible. The review is organized by the type of the Michael acceptor and the Michael donor used in the reaction. [ABSTRACT FROM AUTHOR]

At present, the mainstream industrial synthesis method of polyamide is still bulk fusion polymerization, which is not in line with the concept of green synthesis because of the high threshold of reaction conditions and large energy consumption. Based on this, a new synthesis route of polyamide elastomer was studied in this paper. By synthesizing the end-functionalized long carbon chain diacrylamide (DDA) containing amide bonds, the synthesis mechanism was made by the thiol double bond Michael addition reaction. A series of polyamide elastomers with different ratios of hard and soft segments were synthesized by using dimercaptan chain extenders with different molecular weights. The results showed that the new synthesis route successfully prepared DDA and polyamide elastomers. The mechanical properties of the products were excellent, and the strain rate could reach 383 %. Tensile strength up to 23.08 MPa. The synthesis route has the characteristics of simple reaction process, mild reaction conditions and high reaction conversion rate. It provides theoretical guidance for the new synthesis route of polyamide elastomer. [ABSTRACT FROM AUTHOR]

A chiral sodium glycerophosphate is successfully exploited as a catalyst in the Michael addition of methyl malonate to a number of chalcones. The reactions supplied the target adducts in satisfactory yields and good enantiomeric excesses. A tentative computational study is presented, aiming to understand the reaction mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] Metal ion-catecholate complexes (MCCs) extensively exist in plants and animals, which are in charge of versatile biological functions, such as constructing organs, controlled releasing metal ions and antibacterial. Inspired by this, researchers have exploited various kinds of artificial MCCs, which can serve as structural and functional synthons to construct advanced materials. In terms of the structural contribution, these complexes exhibit not only physical interactions, including metal-coordination, hydrogen bonding, π-π stacking and cation-π interactions, but also rich chemical reactions, including radical polymerization, Schiff base reaction and Michael addition. In terms of functional contribution, the complexes can endow the materials with the intrinsic properties of polyphenols and metal ions, including antioxidant, adhesion, antibacterial, bioimaging and catalyst. In addition, some emerging and fantastic functions are also originally from the complexes, such as tunable mechanical property, self-healing, controlled release and photothermal effect. In this review paper, we comprehensively discuss the recent development of MCC-based materials, including coatings, particles, metallogels and metal–organic frameworks (MOFs). Perspectives in this field has also been put forward as well. [ABSTRACT FROM AUTHOR]

The Michael addition reaction, a cornerstone of contemporary organic synthesis, has witnessed a resurgence of interest owing to its ability to forge intricate carbon‐carbon and carbon‐heteroatom bonds. In the past few years, heterocyclic compounds have been rigorously used as Michael donors, owing to their architectural diversity and distinct reactivity with or without the presence of base/transition metals/organocatalysts. This review encapsulates the latest breakthroughs in chemistry involving Michael addition reaction using heterocyclic compounds as Michael donors. It delivers a comprehensive update on developments in Michael addition reaction triggered by potent heterocycles since 2017, highlighting novel and innovative methodologies, with strategic insights. [ABSTRACT FROM AUTHOR]

In this work, we present basic research on developing thermogel carriers containing high amounts of model antibody immunoglobulin G (IgG) with potential use as injectable molecules. The quantities of IgG loaded into the gel were varied to evaluate the possibility of tuning the dose release. The gel materials were based on blends of thermoresponsive and degradable ABA-type block copolymers composed of poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA–PEG–PLGA) or poly(lactide-co-caprolactone)-b-poly(ethylene glycol)-b-(lactide-co-caprolactone) (PLCL–PEG–PLCL). Primarily, the gels with various amounts of IgG were obtained via thermogelation, where the only factor inducing gel formation was the change in temperature. Next, to control the gels' mechanical properties, degradation rate, and the extent of antibody release, we have tested two approaches. The first one involved the synergistic physical and chemical crosslinking of the copolymers. To achieve this, the hydroxyl groups located at the ends of the PLGA–PEG–PLGA chain were modified into acrylate groups. In this case, the thermogelation was accompanied by chemical crosslinking through the Michael addition reaction. Such an approach increased the dynamic mechanical properties of the gels and simultaneously prolonged their decomposition time. An alternative solution was to suspend crosslinked PEG–polyester nanoparticles loaded with IgG in a PLGA–PEG–PLGA gelling copolymer. We observed that loading IgG into thermogels lowered the gelation temperature (TGEL) value and increased the storage modulus of the gels, as compared with gels without IgG. The prepared gel materials were able to release the IgG from 8 up to 80 days, depending on the gel formulation and on the amount of loaded IgG. The results revealed that additional, chemical crosslinking of the thermogels and also suspension of particles in the polymer matrix substantially extended the duration of IgG release. With proper matching of the gel composition, environmental conditions, and the type and amount of active substances, antibody-containing thermogels can serve as effective IgG delivery materials. [ABSTRACT FROM AUTHOR]

In this study, we explored a method to distinguish between both enolizable regions of unsymmetrical 2,3‐diketones in organocatalytic domino reactions involving nitroalkenes. The selective formation of an enamine from only one side of the molecule was made possible by the use of optically pure 2‐(trifluoromethyl)pyrrolidine. This catalyst, remarkably enhancing the reaction, owes its efficacy to a unique interplay between basicity and nucleophilicity. These features caused the enolization of the substrate at the second possible site to be omitted. The approach resulted in excellent regio‐ diastereo‐ and enantioselectivity (91–99 % ee) across various nitroalkenes, leading to the synthesis of novel cyclopentanone derivatives with three contiguous stereogenic center. [ABSTRACT FROM AUTHOR]

The present study provided an efficient synthesis pathway to the azepino[5,4,3‐cd]indoles using N‐sulfonyl‐1,2,3‐triazoles and 4‐vinylindoles through a cascade carbene insertion and intramolecular aza‐Michael addition. This method is distinguished by mild reaction conditions, straightforward operational steps, accessible starting materials and broad substrate compatibility. Furthermore, the versatility of this reaction with various Michael acceptors significantly broadens the scope of potential substrates. The ability to further transform the resulting multifunctional products underscores the promising applications of this approach in indole nitrogen heterocyclic synthesis. [ABSTRACT FROM AUTHOR]

Novel chiral tetraaza‐bridged calix[4]arene[2]triazine‐based organocatalysts were synthesized and used for catalytic asymmetric Michael reaction of acetylacetone to various aromatic nitrostyrenes. Chiral subunits (R)‐ and (S)‐1,2,3,4‐tetrahydro‐1‐naphthylamine were attached to the tetraaza‐bridged calix[4]arene[2]triazine platform in both enantiomeric forms. The R configuration of the major enantiomer of the Michael product was obtained when 3a was used as catalyst, and the S configuration was obtained when 3b was used as catalyst. This indicated that the configuration of the Michael product was controlled by the chiral calixarene moiety. The Michael adducts were obtained in excellent yields (91%) and enantioselectivities (98%). [ABSTRACT FROM AUTHOR]

A novel UV-curable rosin-based resin, named as DHTM, was synthesized through a Michael addition reaction involving a derivative of natural rosin (dehydroabietylamine, DHAA) and trimethylolpropane triacrylate (TMPTA). The reaction, conducted at a low temperature (50 °C) without solvents, achieved a high conversion rate exceeding 95%. Structural analyses via Fourier transform infrared (FTIR), nuclear magnetic resonance (1H NMR), and liquid chromatography-orthogonal time-of-flight mass spectrometry (LC-OTOF-MS) confirmed the chemical composition of DHTM. Subsequently, a multifunctional UV resin was formulated by combining DHTM with the diluent 4-acryloylmorpholine (ACMO) and cured under UV light. The resulting resin exhibited excellent thermal, mechanical, and microscopic properties, including notable crosslinking density, tensile strength, and adhesion. The addition of ACMO contributed to a smoother resin surface, achieving a higher crosslinking density of 57.04 × 103 mol/m3. In conclusion, the developed UV-curable rosin-based resins exhibit significant potential for applications in UV-curable materials, such as 3D printing and coatings. [ABSTRACT FROM AUTHOR]

N-alkylated C2-symmetric amino acid amide derivatives were shown to catalyse the Michael addition of 2-hydroxy-1,4-napthoquinone to β-nitrostyrene, achieving a maximum ee of 44%. The corresponding trifluoroacetic acid salts also catalysed the aldol reaction between 4-nitrobenzaldehyde and hydroxyacetone, leading to the formation of predominantly syn-aldol products in up to 55% ee. Aspects of the solvent dependence of the aldol reaction and the H-bonding of the catalyst were investigated. [ABSTRACT FROM AUTHOR]

The ion–molecule reaction is one of the most important pathways for the formation of new interstellar chemical species. Herein, infrared spectra of cationic binary clusters of acrylonitrile (AN) with methanethiol (CH3SH) and dimethyl sulfide (CH3SCH3) are measured and compared to those previous studies of AN and methanol (CH3OH) or dimethyl ether (CH3OCH3). The results suggest that the ion–molecular reactions of AN with CH3SH and CH3SCH3 only yield products with S...HN H-bonded or S∴N hemibond structures, rather than the cyclic products as observed in AN-CH3OH and AN-CH3OCH3 studied previously. The Michael addition-cyclization reaction between acrylonitrile and sulfur-containing molecules does not occur due to the weaker acidity of CH bonds in sulfur-containing molecules, which results from their weaker hyperconjugation effect compared to oxygen-containing molecules. The reduced propensity for the proton transfer from the CH bonds hinders the formation of the Michael addition-cyclization product that follows. [ABSTRACT FROM AUTHOR]

The ion–molecule reaction is one of the most important pathways for the formation of new interstellar chemical species. Herein, infrared spectra of cationic binary clusters of acrylonitrile (AN) with methanethiol (CH3SH) and dimethyl sulfide (CH3SCH3) are measured and compared to those previous studies of AN and methanol (CH3OH) or dimethyl ether (CH3OCH3). The results suggest that the ion–molecular reactions of AN with CH3SH and CH3SCH3 only yield products with S...HN H-bonded or S∴N hemibond structures, rather than the cyclic products as observed in AN-CH3OH and AN-CH3OCH3 studied previously. The Michael addition-cyclization reaction between acrylonitrile and sulfur-containing molecules does not occur due to the weaker acidity of CH bonds in sulfur-containing molecules, which results from their weaker hyperconjugation effect compared to oxygen-containing molecules. The reduced propensity for the proton transfer from the CH bonds hinders the formation of the Michael addition-cyclization product that follows. [ABSTRACT FROM AUTHOR]

A cascade inter–intramolecular double Michael strategy for the synthesis of highly functionalized cyclohexanones from curcumins and arylidenemalonates is reported. This strategy works in the presence of aqueous KOH using TBAB as a suitable phase transfer catalyst at room temperature. The functionalized cyclohexanones are formed as major products in moderate to excellent yields with complete diastereoselectivity in most cases. A triple Michael adduct, tetrahydrochromen-4-one, is also formed as a side product in a few cases with excellent diastereoselectivity.

Additive engineering plays a pivotal role in achieving high‐quality light‐absorbing layers for high‐performance and stable perovskite solar cells (PSCs). Various functional groups within the additives exert distinct regulatory effects on the perovskite layer. However, few additive molecules can synergistically fulfill the dual functions of regulating crystallization and passivating defects. Here, we custom‐synthesized 2‐ureido‐4‐pyrimidone (UPy) organic small molecules with diverse functional groups as additives to modulate crystallization and defects in perovskite films via the Michael addition reaction. Theoretical and experimental investigations demonstrate that the −OH groups in UPy exhibit significant effects in fixing uncoordinated Pb2+ ions, passivation of lead‐iodide antisite defects, alleviating hysteresis, and reducing non‐radiative recombination. Furthermore, the enhanced C=O and −NH2 motifs interact with the A‐site cation via hydrogen bonding, which relieves residual strain and adjusts crystal orientation. This strategy effectively controls perovskite crystallization and passivates defects, ultimately enhancing the quality of perovskite films. Consequently, the open‐circuit voltage of the UPy‐based p‐i‐n PSCs reaches 1.20 V, and the fill factor surpasses 84 %. The champion device delivers a power conversion efficiency of 25.75 %. Remarkably, the unencapsulated device maintained 96.9 % and 94.5 % of its initial efficiency following 3,360 hours of dark storage and 1,866 hours of 1‐sun illumination, respectively. [ABSTRACT FROM AUTHOR]

A highly enantioselective Pd/Bim-catalyzed dearomative Michael reaction applying polycyclic tropones as non-benzenoid aromatic Michael acceptors and arylboronic acids as aryl pronucleophiles has been developed. The bridged biaryls bearing central and axial chirality, including pentacyclic cyclohepta[b]indoles and 6,7-dihydrodibenzo- [a,c][7]annulen-5-ones, are generally generated in good to high yields and excellent enantioselectivities and can be readily transformed into useful derivatives. [ABSTRACT FROM AUTHOR]

The enantiodivergent synthesis of syn‐Michael adducts can be easily achieved by switching the terminal proline in dipeptidic proline‐thiourea catalysts. In this study, a dipeptidic proline‐derived thiourea organocatalyst was rationally designed and facilely prepared from dipeptidic proline, a chiral diamine as a linker, and isothiocyanate. This asymmetric bifunctional catalyst for Michael addition between aldehydes and nitroolefins provided chiral 4‐nitro aldehyde adducts with yields of up to 99 %, 92 : 8 syn‐diastereoselectivity, and 97 % enantiomeric excess at room temperature. [ABSTRACT FROM AUTHOR]

An efficient organocatalytic cascade vinylogous Michael‐cyclization to construct the challenging full substituted cyclohexa‐1,3‐dienes has been developed. Catalyzed by the cinchona alkaloids‐derived thiourea VIII at −60 °C, the products were obtained as a single diastereomer with two contiguous stereocenters and more than four different useful functional groups in moderate to good yields and good to excellent enantioselectivities. [ABSTRACT FROM AUTHOR]

Endothelialization is important for offering an anticoagulant surface, which is crucial for the construction of tissue‐engineered heart valves. Silk sericin is extensively investigated in the biomedical field due to its remarkable biological activities and diverse functional groups, favoring chemical modifications for the formation of versatile constructs. Herein, a sericin covalently modified valve (SCMV) is successfully fabricated by coupling maleylated silk sericin (MSS) with thiolated decellularized heart valve (DHV) through a Michael addition reaction. The results demonstrate that SCMV exhibits a smooth surface, higher hydrophilicity, and excellent resistance to platelets adhesion compared to DHV. Additionally, SCMV promotes endothelial cells (ECs) adhesion under both static and flow conditions and enhances their survival in a mouse subcutaneous implant model. The study also discovered that MSS‐stimulated ECs exhibit increased RhoA activation, expression of rho‐associated protein kinase 2 (ROCK2) and phosphorylated myosin light chain 2 (MLC2), actin polymerization, and cell adhesion; whereas actin organization and cell adhesion are significantly reduced by treatment with Y‐27632, a ROCK inhibitor. Furthermore, several integrin subunits, including α1, α2, α3, α5, α6, β1, β3, and β5, are involved in this regulatory process. Collectively, the findings highlight the potential application of silk sericin in promoting endothelialization of DHV while uncovering novel mechanisms underlying its regulatory effect on ECs adhesion. [ABSTRACT FROM AUTHOR]

The reaction of diethyl 2,3-dicyanofumarate with carbo- and heterocyclic 1,3-dicarbonyl compounds resulted in a [3+3] annulation with the formation of condensed diethyl 2-amino-4-cyano-4H-pyran-3,4-dicarboxylates. The cascade transformation involved the Michael addition of the enol form of the CH acid to the double bond of diethyl 2,3-dicyanofumarate followed by the Thorpe–Ziegler cyclization. [ABSTRACT FROM AUTHOR]

We herein reported a sustainable synthesis of 3,3-disubstituted oxindoles via a Michael-type reaction based on the CuBr-catalysed capture of carboxylic oxonium ylides with isatylidene malononitrile. The reaction is characterized by a high atom economy and low economic constraints. The catalyst CuBr could be conveniently recyclized. The products of the reaction were found to be inhibitory against Na ion channels. We expect the reaction to shed the light on synthesis of biologically interesting molecules directed by principles of green chemistry. [ABSTRACT FROM AUTHOR]

A method was developed for the synthesis of compounds of a new series of 5,7-diaryl-6-nitro-4,5,6,7-tetrahydroazolo[1,5-a]pyrimidines under the conditions of the Michael reaction between the corresponding triazole-containing Schiff bases and β-nitrostyrene derivative followed by additional heterocyclization. The oxidation of the resulting tetrahydro derivatives with manganese(iv) oxide made it possible to prepare previously unknown functional derivatives of 2-substituted 5,7-bis(4-methoxyphenyl)-6-nitro-1,2,4-triazolo-[1,5-a]pyrimidines, whose structures were determined using NMR correlation spectroscopy (1H—1H NOESY, 1H—13C HMBC). [ABSTRACT FROM AUTHOR]

Synthesis of monomer‐recyclable polyesters solely from CO2 and bulk olefins holds great potential in significantly reducing CO2 emissions and addressing the issue of plastic pollution. Due to the kinetic disadvantage of direct copolymerization of CO2 and bulk olefins compared to homopolymerization of bulk olefins, considerable research attention has been devoted to synthesis of polyester via the ring‐opening polymerization (ROP) of a six‐membered disubstituted lactone intermediate, 1,2‐ethylidene‐6‐vinyl‐tetrahydro‐2H‐pyran‐2‐one (휹‐L), obtained from telomerization of CO2 and 1,3‐butadiene. However, the conjugate olefin on the six‐membered ring of 휹‐L leads to serious Michael addition side reactions. Thus, the selective ROP of 휹‐L, which can precisely control the repeating unit for the production of polyesters potentially amenable to efficient monomer recycling, remains an unresolved challenge. Herein, the first example of selective ROP of 휹‐L is reported using a combination of organobase and N,N′‐Bis[3,5‐bis(trifluoromethyl)phenyl]urea as the catalytic system. Systematic modifications of the substituent of the urea show that the presence of electron‐deficient 3,5‐bis(trifluoromethyl)‐phenyl groups is the key to the extraordinary selectivity of ring opening over Michael addition. Efficient monomer recovery of oligo(휹‐L) is also achieved under mild catalytic conditions. [ABSTRACT FROM AUTHOR]

The chemical reduction within a family of organic selenocyanates, as masked selenols, using reducing agents, such as Rongalite, sodium dithionite, and sodium thiosulfate is investigated. Using Rongalite, the corresponding diselenides were obtained quantitatively and selectively in very good to excellent yields (51–100 %) starting from alkyl, aryl, and benzyl selenocyanates. The scope of the reaction is unaffected by the electronic nature of the substituents. Furthermore, the reducing agent, Rongalite, is compatible with hydrolysable and reducing‐sensitive functional groups. Additionally, a simple methodology employing the in‐situ generated benzyl selenolate anion (PhCH2Se−) to promote aliphatic nucleophilic substitution, epoxide ring opening, and Michael addition reactions has been developed; thus, extending the structural diversity of the synthesized selenium derivatives. [ABSTRACT FROM AUTHOR]

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]

In the present research, the physicochemical properties including electronic and structural properties and antioxidant activity of six fluorinated flavone derivatives have been discussed using of density functional theory calculations. Benchmarking studies of the DFT-B3LYP/6–311 + G(d, p) computational method were done using experimental 1HNMR and 13CNMR data of flavones 2 and 5. The experimental and calculated spectral data are in very good agreement with R2 < 92%. Using the DFT-B3LYP/6–311 + G(d, p) method, bond lengths and bond angles, intramolecular hydrogen interactions, EHOMO and ELUMO, electrophilicity index, and reactivity against active oxygen radicals were investigated. The local electrophilicity indices were calculated for flavones 1–6. Three reactive centers can be considered for nucleophilic attack on flavones 1–6. The data showed that the most active center is C9 on the 4-pyrone ring, conducting the Michael reaction, and the presence of -CF3 group on these compounds increases the electrophilic properties of flavones 1–6. Using three mechanisms of hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT), and the sequential proton loss electron transfer (SPLET) mechanisms, antioxidant activity of the studied flavones was investigated and compared with data for phenol. The presence of intramolecular hydrogen bonds strongly affects the antioxidant properties. According to the above-mentioned mechanisms, antioxidant activity of studied flavones 1–6 is higher than that of phenol. The presence of fluorine atom has a significant effect on their physicochemical properties. [ABSTRACT FROM AUTHOR]

A facile strategy to construct superhydrophobic coatings was carried out by one‐pot process using novel nano zero‐valent iron and hydrogen peroxide as trigger in ethanol and Tris buffer mixed system containing dopamine and 1H,1H,2H,2H‐perfluorodecanethiol (PFDT) for the first time. The polydopamine (PDA) modified by PFDT composite coating can be deposited onto various substrates including glass slides, polyurethane sheets, polytetrafluoroethylene wafers, 304 stainless steel sheets, and polyurethane sponges, revealing excellent hydrophobicity with the water contact angles from 157.1° to 162.2° and the sliding angle lower than 1°. The flourier transformed infrared spectroscopy and x‐ray photoelectron spectroscopy information of the composite coating demonstrated the successful covalent interaction between catechol group in PDA and thiol group of PFDT via Michael addition reaction. As‐prepared PFDT/PDA composite coatings exhibited enhanced chemical stability in highly acidic solutions for 6 days, alkaline aqueous solutions for 5 days, salty solutions (3.5 wt%) for 28 days, and polar organic solvents for 24 h, respectively, as well as resistance to algae adhesion. The excellent corrosion resistance and chemical stability of the composite coating and their simple, time saving and inexpensive construction process are expected to be widely applied in various areas, including marine anti‐corrosion, anti‐fouling, and oil–water separation. [ABSTRACT FROM AUTHOR]

Pulsed ultrasonic irradiation with on‐off modulation remarkably enhances asymmetric noncovalent organocatalysis "on water", specifically for Michael addition and Diels‐Alder reactions. This approach effectively addresses challenges associated with solid reactant dispersion encountered in "on‐water" reactions and mitigates overheating issues caused by continuous ultrasound exposure, thereby significantly augmenting reaction rates and stereoselectivities. [ABSTRACT FROM AUTHOR]

A novel synthesis method has been developed for the construction of functionalized 2,4-diarylpyridines. The reaction involves several key processes, including a reduction reaction, Michael reaction, decarboxylation, intramolecular cyclization, oxidation, ring-opening and aromatization reaction. All of these processes are facilitated by heating a mixture of the starting materials in an environmentally benign solvent, propylene carbonate (PC), with the oxidant (air) and the catalyst Cu(OAc)2. This cascade reaction not only forms two new bonds but also cleaves three existing bonds in a single pot. The protocol presented in this study is a valuable tool for synthesizing functionalized unsymmetrical 2,4-diarylpyridines. [ABSTRACT FROM AUTHOR]

To the best of our knowledge, enzymes that catalyse intramolecular Diels-Alder ([4+2] cycloaddition) reactions are frequently reported in natural product biosynthesis; however, no native enzymes utilising Lewis acid catalysis have been reported. Verticilactam is a representative member of polycyclic macrolactams, presumably produced by spontaneous cycloaddition. We report that the intramolecular [4+2] cycloadditions can be significantly accelerated by ferredoxins (Fds), a class of small iron-sulphur (Fe-S) proteins. Through iron atom substitution by Lewis acidic gallium (Ga) iron and computational calculations, we confirm that the ubiquitous Fe-S cluster efficiently functions as Lewis acid to accelerate the tandem [4+2] cycloaddition and Michael addition reactions by lowering free energy barriers. Our work highlights Nature's ingenious strategy to generate complex molecule structures using the ubiquitous Fe-S protein. Furthermore, our study sheds light on the future design of Fd as a versatile Lewis acid catalyst for [4+2] cycloaddition reactions. Native enzymes using Lewis acid catalysis in intramolecular [4+2] cycloaddition remain unreported. Herein, the authors report the ferredoxins catalyzed [4+2] cycloaddition in polycyclic macrolactam verticilactam biosynthesis using a transition-metal center. [ABSTRACT FROM AUTHOR]

– In a simple and efficient convenient method, a series of new fused heterocycles of [1,3]thiazolo[4,5-d]-pyrimidines, 4a–4c were synthesized with good yields. As starting materials, thiosemicarbazide was condensed with 4-N,N-dimethylbenzaldehyde to afford thiosemicarbazone 1 which further cyclized with mercaptoacetic acid to produce 4-thiazolidinone 2. Furthermore, chalcones 3a–3c was prepared through fusion of 4-thiazolidinones with various aldehydes. Finally, the entitled compounds 4a–4c has been obtained via Michael addition reaction of 4-thiazolidinones with thiourea. The chemical structures for all new compounds were deduced from their elemental and spectral analysis. [ABSTRACT FROM AUTHOR]

An efficient one-pot synthesis of 1,3-diketones has been synthesized starting from alkynones using a Michael addition–nucleophilic substitution reaction process. The reaction starts with the Michael addition of imidazoles to alkynones, followed by the nucleophilic substitution by water. The final product 1,3-diketones were characterized by the NMR spectra. This study demonstrated that such reactions could successfully occur in one pot under mild conditions with a high yield of 1,3-diketones from 65 to 93%. [ABSTRACT FROM AUTHOR]

Cinchona alkaloid-derived sulfonamides and ester dimers containing chiral hyperbranched polymers have been successfully synthesized and applied as catalysts in asymmetric reactions. Several hyperbranched polymers derived from cinchona alkaloids, incorporating sulfonamides and esters, were synthesized through Mizoroki--Heck coupling polymerization. These polymers were subsequently applied in enantioselective Michael addition reactions. As the prepared polymers are not soluble in frequently used organic solvents, they act as efficient catalysts in the enantioselective reaction of β-ketoesters to nitroolefins, achieving up to 99% enantioselectivity with good yields. The insoluble property allows them to better satisfy "green chemistry" requirements and be used several times without losing the enantioselectivity. [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]

3,4-Fused pyrrolocoumarins, synthetically prepared or naturally occurring, possess interesting biological properties. In this review, the synthetic strategies for the synthesis of the title compounds are presented along with their biological activities. Two routes are followed for that synthesis. In one, the pyrrole ring is formed from coumarin derivatives, such as aminocoumarins or other coumarins. In the other approach, the pyranone moiety is built from an existing pyrrole derivative or through the simultaneous formation of coumarin and pyrrole frameworks. The above syntheses are achieved via 1,3-dipolar cycloaddition reactions, Michael reaction, aza-Claisen rearrangement reactions, multi-component reactions (MCR), as well as metal-catalyzed reactions. Pyrrolocoumarins present cytotoxic, antifungal, antibacterial, α-glucosidase inhibition, antioxidant, lipoxygenase (LOX) inhibition, and fluorescent activities, as well as benzodiazepine receptor ability. [ABSTRACT FROM AUTHOR]

1,8‐Diazabicyclo[5.4.0]undec‐7‐ene (DBU) catalyzed Michael addition reactions between α,β‐unsaturated esters and benzophenone‐imines of glycine esters have been realized in THF at room temperature by using LiBr as an additive, effectively enabling the glutamation of phenols, thiophenols, secondary amines and imides. 3‐Substituted glutamic acid esters were obtained in excellent yields and diastereoselectivities (up to quantitative yield and >20 : 1 dr). These glutamic acid esters were readily converted into their corresponding pyroglutamic acid esters in high yields through acidic hydrolysis followed by lactamization. [ABSTRACT FROM AUTHOR]

Breast cancer has overtaken lung cancer as the number one cancer worldwide. Paclitaxel (PTX) is a widely used first‐line anti‐cancer drug, but it is not very effective in clinical breast cancer therapy. It has been reported that triptolide (TPL) can enhance the anticancer effect of paclitaxel, and better synergistic therapeutic effects are seen with concomitant administration of PTX and TPL. In this study, we developed pH‐responsive polymeric micelles for co‐delivery of PTX and TPL, which disassembling in acidic tumour microenvironments to target drug release and effectively kill breast cancer cells. Firstly, we synthesized amphiphilic copolymer mPEG2000‐PBAE through Michael addition reaction, confirmed by various characterizations. Polymer micelles loaded with TPL and PTX (TPL/PTX‐PMs) were prepared by the thin film dispersion method. The average particle size of TPL/PTX‐PMs was 97.29 ± 1.63 nm, with PDI of 0.237 ± 0.003 and Zeta potential of 9.57 ± 0.80 mV, LC% was 6.19 ± 0.21%, EE% was 88.67 ± 3.06%. Carrier material biocompatibility and loaded micelle cytotoxicity were assessed using the CCK‐8 method, demonstrating excellent biocompatibility. Under the same drug concentration, TPL/PTX‐PMs were the most toxic to tumour cells and had the strongest proliferation inhibitory effect. Cellular uptake assays revealed that TPL/PTX‐PMs significantly increased intracellular drug concentration and enhanced antitumor activity. Overall, pH‐responsive micellar co‐delivery of TPL and PTX is a promising approach for breast cancer therapy. [ABSTRACT FROM AUTHOR]

Fused 2-amino-3-cyano-4H-pyrans were synthesized by the tandem Knoevenagel—Michael reaction. A previously unknown version of the ring opening of 2-amino-3-cyano-4H-pyrans giving substituted 2,6-dicyanoaniline was discovered. The structure of the latter compound was established by X-ray diffraction. [ABSTRACT FROM AUTHOR]

Herein, we present a unified chemical synthesis of three subgroups of cephalotaxus diterpenoids. Key to the success lies in adopting a synthetic strategy that is inspired by biosynthesis but is opposite in nature. By employing selective one‐carbon introduction and ring expansion operations, we have successfully converted cephalotane‐type C18 dinorditerpenoids (using cephanolide B as a starting material) into troponoid‐type C19 norditerpenoids and intact cephalotane‐type C20 diterpenoids. This synthetic approach has enabled us to synthesize cephinoid H, 13‐oxo‐cephinoid H, 7‐oxo‐cephinoid H, fortalpinoid C, 7‐epi‐fortalpinoid C, cephanolide E, and 13‐epi‐cephanolide E. Furthermore, through the development of an intermolecular asymmetric Michael reaction between β‐oxo esters and β‐substituted enones, we have achieved the enantioselective synthesis of advanced intermediates within our synthetic sequence, thus formally realizing the asymmetric total synthesis of the cephalotaxus diterpenoids family. [ABSTRACT FROM AUTHOR]