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Phenolic compounds have long captivated the interest of organic synthesis, particularly in their quest for selective hydroxylation of arenes using H2O as a hydroxyl source. However, the inherent high reactivity and low redox potential of phenols often lead to undesirable overoxidation byproducts. To address this challenge, herein, we develop an electrophotochemical approach, finetuning substrate oxidative potential and enabling para-selective hydroxylation of anilides. This method showcases versatility, accommodating a wide array of substrates, while revealing high regional selectivity and compatibility with diverse functional groups. Moreover, the protocol allows facile late-stage functionalization of biologically active molecules. Mechanistic investigations demonstrate the activation of anilides by the excited state photocatalyst, effectively decreasing their oxidative potential and enhancing regional selectivity during hydroxylation. By using this protocol, important drug molecules such as Paracetamol, Fenretinide, Practolol, and AM404 could be synthesized, demonstrating the applicability of this approach in drug synthesis and late-stage functionalization. Phenolic compounds have long captivated the interest of organic synthesis, particularly in their quest for selective hydroxylation of arenes using H2O as a hydroxyl source but the inherent high reactivity and low redox potential of phenols often lead to undesirable overoxidation byproducts. Here the authors develop an electrophotochemical approach, finetuning substrate oxidative potential and enabling para-selective hydroxylation of anilides. [ABSTRACT FROM AUTHOR]

tert‐Butyl hydroperoxide (tBuOOH, TBHP) is a commonly used hydroperoxide in many oxidation processes. The primary factors contributing to the increasing usefulness of TBHP include its affordability, eco‐friendliness, exceptional efficacy, and capacity to substitute harmful or rare heavy metal oxidants. In this sexennial update, we thoroughly and critically examined the most noteworthy applications of TBHP in C−H functionalization and heteroatom‐heteroatom bond formation reactions from 2018 till the present. The review has been subdivided based on the nature of the bonds being formed. The review focuses on the advantages and disadvantages of using synthetic organic transformations, as well as the breadth of their use and the underlying mechanisms involved. [ABSTRACT FROM AUTHOR]

This review provides an overview of the recent advances in the synthesis of diverse heterocyclic compounds using thiosemicarbazide as a key building block via multicomponent reactions. Thiosemicarbazide is a versatile reagent that has gained significant attention in organic synthesis due to its ability to participate in diverse multicomponent reactions for the efficient and sustainable construction and assembly of novel bioactive molecules and pharmaceuticals. This review discusses the potential applications and future directions in this rapidly evolving area of research. It provides valuable insights into the innovative approaches for the synthesis of heterocycles using thiosemicarbazide, showcasing its significance in modern organic chemistry research. In summary, this review provides an overview of the current state of the art, highlighting the use of thiosemicarbazide in the synthesis of novel heterocyclic compounds reported between 2015 and early 2024. [ABSTRACT FROM AUTHOR]

Drawing inspiration from nature has long been a cornerstone of chemical innovation, with natural systems offering a wealth of untapped potential for discovery. In this minireview, we delve into the burgeoning field of cobaloxime catalysis in organic synthesis, which mimics the catalytic activity of the natural organometallic alkylcobalamine enzymes. Our focus lies on elucidating the latest advancements in this area, as well as delineating the primary mechanistic pathways at play. By describing, and comparing these mechanisms, we provide a comprehensive overview of the current state‐of‐the‐art, while also shedding light on the key unresolved challenges that await further exploration. [ABSTRACT FROM AUTHOR]

Mechanochemistry, as an enabling technology, harnesses mechanical force to drive chemical reactions, presenting compelling advantages in organic synthesis within the principles of green chemistry. This review explores how its unique advantages and alignment with sustainable practices have been widely developed in different scientific fields in Italy. As a transformative strategy for organic synthesis, mechanochemistry has been portrayed in this review as a valuable synthetic alternative due to the various advantages, such as solvent reduction and new reaction pathways, that its use brings. Nonetheless, the improvements brought about by its use have also been crucial in other fields of chemistry described by Italian scientists. In this whole context, Italian researchers have analysed both already optimised processes and new feasible pathways, paving the way for new avenues previously hampered by all the limitations that belong to in‐solution chemistry. [ABSTRACT FROM AUTHOR]

Persistent radicals facilitate numerous selective radical coupling reactions. Here, we have identified acyl triazole as a new and versatile moiety for generating persistent radical intermediates through single-electron transfer processes. The efficient generation of these persistent radicals is facilitated by the formation of substrate-coordinated cobalt complexes, which subsequently engage in radical cross-coupling reactions. Remarkably, triazole-coordinated cobalt complexes exhibit metal-hydride hydrogen atom transfer (MHAT) capabilities with alkenes, enabling the efficient synthesis of diverse ketone products without the need for external ligands. By leveraging the persistent radical effect, this catalytic approach also allows for the development of other radical cross-coupling reactions with two representative radical precursors. The discovery of acyl triazoles as effective substrates for generating persistent radicals and as ligands for cobalt catalysis, combined with the bifunctional nature of the cobalt catalytic system, opens up new avenues for the design and development of efficient and sustainable organic transformations. Persistent radical-mediated cross-coupling has emerged as a powerful tool in organic synthesis for forging new C–C bonds. Here, the authors identify acyl triazoles as a versatile moiety for generating persistent radical intermediates through single-electron transfer processes, in the context of cobalt-catalysed carbon-carbon couplings under photoirradiation. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) cell is an ideal platform for organic transformation because of its green benefits and minimal energy consumption. As an emerging methodology, the reaction types of photoelectrocatalytic organic synthesis (PECOS) are limited to simple oxidation and C–H activation at current stage. Metal catalysis for the construction of C(sp2)–N bonds has not been touched yet in PECOS. We introduce here a PEC method that successfully engages Ni catalysis for the mild production of aniline derivatives. Experimental and computational investigations elucidate that the addition of photoanode-generated amine radical to Ni catalyst avoids the sluggish nucleophilic attack, enabling the reaction to proceed at an ultra-low potential (–0.4 V vs. Ag/AgNO3) and preventing the overoxidation of products in conventional electrochemical synthesis. This synergistic catalysis strategy exhibits good functional group tolerance and wide substrate scope on both aryl halides and amines, by which some important natural products and pharmaceutical chemicals have been successfully modified. The reaction types of photoelectrocatalytic organic synthesis (PECOS) are limited to simple oxidation and C–H activation at current stage while metal catalysis for the construction of C(sp2)–N bonds remains unexplored. Here, the authors introduce a PEC method that successfully engages Ni catalysis for the mild production of aniline derivatives. [ABSTRACT FROM AUTHOR]

The combination of chemo- and photocatalyses with biocatalysis, which couples the flexible reactivity of the photo- and chemocatalysts with the highly selective and environmentally friendly nature of enzymes in one-pot linear cascades, represents a powerful tool in organic synthesis. However, the combination of photo-, chemo- and biocatalysts in one-pot is challenging because the optimal operating conditions of the involved catalyst types may be rather different, and the different stabilities of catalysts and their mutual deactivation are additional problems often encountered in one-pot cascade processes. This review explores a large number of transformations and approaches adopted for combining enzymes and chemo- and photocatalytic processes in a successful way to achieve valuable chemicals and valorisation of biomass. Moreover, the strategies for solving incompatibility issues in chemo-enzymatic reactions are analysed, introducing recent examples of the application of non-conventional solvents, enzyme–metal hybrid catalysts, and spatial compartmentalization strategies to implement chemo-enzymatic cascade processes. [ABSTRACT FROM AUTHOR]

Rotaxanes are mechanically interlocked molecules where a ring (macrocycle) is threaded onto a linear molecule (thread). The position of the macrocycle on different stations on the thread can be controlled in response to external stimuli, making rotaxanes applicable as molecular switches. Here we show that bistable rotaxanes based on the combination of a Zn(II) tetraphenylporphyrin photosensitizer, attached to the macrocycle, and a black-hole-quencher, attached to the thread, are capable of singlet oxygen production which can be switched on/off by the addition of base/acid. However, we found that only a sufficiently long linker between both stations on the thread enabled switchability, and that the direction of switching was inversed with regard to the original design. This unexpected behavior was attributed to intramolecular folding of the rotaxanes, as indicated by extensive theoretical calculations. This evidences the importance to take into account the conformational flexibility of large molecular structures when designing functional switchable systems. Singlet oxygen is a highly useful reagent for organic synthesis, disinfection and photodynamic therapy, but its high reactivity calls for systems where its photochemical generation can be switched on and off on demand. Here, the authors report porphyrin-decorated pH-switchable [2]rotaxanes for singlet oxygen photoproduction, finding that molecular folding of the rotaxanes influences the on/off switching in an unforeseen way. [ABSTRACT FROM AUTHOR]

Iron(III)- and iodide-promoted efficient synthesis of pyrimidines from biomass-based alkyl lactates, inorganic ammonium, and aldehydes was carried out. This multicomponent reaction efficiently proceeded through a series of condensation, dehydrogenation coupling, and condensation steps to form C–N and C–C bonds, respectively. This protocol strikingly features sustainable catalysis using Earth-abundant metals and NH4I as a substrate and catalyst. When using biomass-based alkyl lactate as a raw material, the alkyl lactate can be reused, and clean byproducts can be obtained. More than 30 pyrimidines and 7 triazines were synthesized in isolated yields of up to 92%. In addition, the analysis of several dimensions of green indicators proves the greenness of this work. Promising applications of biobased alcohols and inorganic salts in sustainable organic synthesis are represented by this work. [ABSTRACT FROM AUTHOR]

Aromatic nitro compounds are important intermediates in synthetic organic chemistry. In this work, catechol was used as raw materials, and nitro‐catechol derivatives with different alkylation substitutions were synthesized using two different synthetic routes. More than 15 new previously undescribed compounds were obtained. Each compound was meticulously characterized using a suite of physicochemical techniques, with selective compounds further analyzed via X‐Ray diffraction to ascertain their structure. These newly synthesized compounds hold significant promise as candidates for further chemical modification, which underlines their potential usefulness in the field of the fine synthesis of organic compounds. [ABSTRACT FROM AUTHOR]

Accessing versatile C(sp3)−C(sp3) bond through the cross‐electrophile coupling of two distinct etheric C−O bonds is crucial in organic synthesis but remains barely explored. Herein, we report an innovative photoinduced low‐valent zirconocene catalysis enabling the reductive coupling of ethers with high activity and cross‐selectivity. Mechanistic investigation suggests that photoexcitation of low‐valent zirconocene facilitates the C(sp3)−O bond scission of benzylic ethers, leading to the benzylic radicals intermediate via a single‐electron reduction pathway. The subsequent recombination of this benzylic radical with the Zr center followed by carbomagnesiation generates benzylic Grignard reagents for downstream coupling with aliphatic ethers through an SN2‐like mechanism. In application, a wide range of ethers readily in situ derived from aldehydes and ketones becomes feasible with high functional group compatibility as well as excellent cross‐selectivity. [ABSTRACT FROM AUTHOR]

This study highlights the significance of the Ullmann coupling reaction in modern organic synthesis and advances catalytic methodologies through the introduction of a kanamycin−copper complex as a highly efficient catalyst for the synthesis of diverse N−aryl compounds. We demonstrate the catalyst's versatility by synthesizing 20 diaryl−amine instances, 21 Ar(het)−N compounds, and 10 miscellaneous examples. NMR, IR, and UV spectroscopy offer insights into the catalyst's behaviour. Additionally, DFT studies support the catalyst's proficiency in generating SO4−⋅ radicals by stabilizing with amino sugar moieties. Ex‐situ NMR experiments confirm a ternary complex‐based mechanism at concentrations below 0.1 μM. Furthermore, we showcase the degradation of methylene blue to its precursor amine under optimized conditions. Overall, this research underscores the potential of Ullmann condensation reactions in contemporary organic synthesis and contributes significantly to the advancement of catalytic methodologies. [ABSTRACT FROM AUTHOR]

Catalytic fixed-bed is an efficient and facile system for scalable organic synthesis due to its continuous and fast flow operation process. As a key unit in the fixed-bed system, catalytically active packing materials are required to possess some properties, such as high activity, excellent stability, and porous packing structure. Herein, we prepare a fibrous fixed-bed catalyst by anchoring Pd nanoparticles on N-doped graphene fiber (NHG) (Pd/NGF). Due to the porous and loose packing structure, the resultant Pd/NGF catalyst can be easily filled into the continuous-flow reactor to construct a fixed-bed system with low flow resistance. The corresponding catalytic fixed-bed system exhibits a favourable flow rate (8 mL/min) and excellent durability toward reduction reactions of N-containing unsaturated compounds to produce aromatic amines. This work provides a new design concept of fibrous fixed-bed catalysts with dual-active components (i.e., graphene-derived active materials and metal nanoparticles) and catalytic organic synthesis in a continuous-flow process. [ABSTRACT FROM AUTHOR]

The realm of application of organometallic catalysis to organic synthesis has witnessed a transformative shift in recent years, owing much to the evolution of ate complexes from mere reagents to versatile catalysts. Ate complexes, formed through the coordination of a neutral Lewis acid with an organic anionic base, have emerged as pivotal intermediates that not only facilitate organic transformations but also serve as efficient catalysts in a wide range of chemical reactions. This review presents the fascinating journey of ate complexes, highlighting their development from stoichiometric reagents to active catalysts. Historically, ate complexes were primarily regarded as stoichiometric species essential for various metal-catalyzed transformations. However, constant research has unveiled their potential as catalysts in their own right, reshaping the landscape of modern organic synthesis. In this minireview, we discuss the pivotal role of ate complexes in the evolution of organic synthesis, from their early days as reactive intermediates to their current stature as catalytic pioneers offering a glimpse into the exciting future of this dynamic field. [ABSTRACT FROM AUTHOR]

The halogenation of alkenes is a crucial pathway in forming C-X bonds, with a significant impact on organic synthesis and pharmaceuticals. However, traditional methodologies present potential hazards to both the environment and human health, making the quest for green and efficient halogenation methods paramount. In this study, we introduce a novel iron catalyst based on a polyoxometalate, (NH4)3[FeMo6O18(OH)6], simplified as Fe(III)Mo6. Employing this catalyst, a plethora of styrene derivatives and alcohols were efficiently and successfully converted to the corresponding halogenated products. Also, our catalyst showed excellent performance toward the reaction with various substrates. Moreover, it demonstrates high stability and activity in the cycle test. In addition, we also described the reaction mechanism based on the control experiment. The catalyst exhibits non-toxic, green, and environmentally friendly characteristics that provide future industrialization potential. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Axially chiral biaryls represent the most important class of atropisomers, and they widely exist in natural products and biologically active molecules. They also constitute a unique scaffold for chiral ligands and catalysts in organic synthesis. The development of synthetic methods to obtain such chiral compounds has received widespread attention, among which catalytically atroposelective ring‐opening of configurationally labile compounds represents one of the most attractive strategies. Various substrates with strained cyclic structures, such as the renowned Bringmann's lactones, can undergo asymmetric transformation into stable atropisomers. Known advancement primarily relies on metal catalyst combined with well‐designed chiral ligands, the approaches utilizing organocatalysis as a critical resolution strategy are notably scarce. In this study, we disclosed a N‐heterocyclic carbene (NHC)‐catalyzed asymmetric ring‐opening reaction of biaryl lactams via direct atroposelective nucleophilic activation. The optimized bulky carbene catalyst ensures that the reaction can proceed under mild conditions, affording the desired product with good to excellent yields and atroposelectivity. [ABSTRACT FROM AUTHOR]

This concept article explores the emerging role of atropisomerism in foldamer chemistry, a field focussed on oligomers that adopt well‐defined conformations through non‐covalent interactions. Atropisomerism introduces a novel dimension to foldamer design by restricting rotational freedom around single bonds to dictate molecular shape with precision. Despite the prevalence of atropisomeric bonds in organic synthesis, their application within foldamers remains underexplored. Here, we discuss key developments in both backbone and sidechain atropisomerism, and suggest future directions for atropisomeric foldamers in the context of a recent surge in atropselective synthetic methods. We propose that judicious use of atropisomerism may serve as a transformative tool in the construction of shape‐defined macromolecules. [ABSTRACT FROM AUTHOR]

In this Synpacts article, we describe the concept of cyclodimerization in the biosynthesis and biomimetic synthesis of natural products and unnatural products. We also discuss key details of our discovery and development of a biomimetic-like, selective, homo- and heterochiral cyclodimerization strategy for the construction of nonnatural dimeric carbazole frameworks by employing a formal [3+2] annulation. Our work also demonstrated a novel reactivity of 1-(indol-2-yl)pent-4-yn-3-ols, and their potential as new synthetic building blocks in organic synthesis. 1 Introduction: Chiral Cyclodimerization Reactions 2 Biomimetic Syntheses of Natural Products through Chiral Cyclodimerizations 3 Bioinspired Synthesis of Nonnatural Dimeric Carbazoles through Selective Chiral Cyclodimerizations 4 Future Perspectives and Conclusions [ABSTRACT FROM AUTHOR]

Recent advances in the isolation of tamed bismuth radicals and the selective in situ generation of highly reactive bismuth radicals have set the stage for the application of these compounds in organic and organometallic synthesis and catalysis. Here, we provide a summary of the methodological approaches in the field. Important strategies for accessing bismuth radical species are presented and key examples of their applications in organic synthesis are outlined, highlighting how this class of compounds has emerged as new set of valuable tools for synthetic practitioners. 1 Introduction 2 Generation of Bismuth Radical Species by Homolysis 2.1 Temperature-Induced Homolysis 2.2 Light-Induced Homolysis 2.3 Light-/Temperature-Induced Bi–C Homolysis of Polar Oxidative Addition Complexes 3 Applications of Bismuth-Centered Radical Species in Organic Synthesis 3.1 Bismuth-Catalyzed Cycloisomerization of Iodo Olefins 3.2 Controlled Radical Polymerization Reactions 3.3 Bismuth-Promoted Pn–Pn and C–S Coupling 3.4 Bismuth-Catalyzed Dehydrocoupling of Silanes with TEMPO 3.5 Bismuth-Catalyzed C–N Coupling with Redox-Active Electrophiles 3.6 Bismuth-Catalyzed Giese-Type Coupling Reactions 3.7 Oxidative Addition of Aryl Electrophiles to Photoactive Bismuthinidenes 4 Conclusions [ABSTRACT FROM AUTHOR]

Triazolopyrimidine compounds containing carboxyl and thioether groups were synthesized using 3-amino5-mercapto-1,2,4-triazole, benzyl bromide, and diethyl ethoxymethylenemalonate (EMME) as starting materials. The synthesis involved nucleophilic substitution, cyclization, and hydrolysis reactions. The resulting products were characterized and analyzed for their structures. The experiment included techniques such as heating reflux, TLC (thinlayer chromatography) detection, filtration, and recrystallization, which aimed to enhance students' skills in multi-step organic compound synthesis and spectral analysis. Triazolopyrimidine compounds are widely found in natural products and pharmaceuticals. The synthesis of these compounds not only provides insight into societal demands but also integrates cutting-edge research and theoretical knowledge taught in the classroom, thereby improving the quality of experimental teaching and achieving excellent educational outcomes. [ABSTRACT FROM AUTHOR]

A two-step synthetic experiment to produce paracetamol from 4-hydroxyacetophenone was designed for undergraduate organic chemistry courses. The experiment begins with the condensation of 4-hydroxyacetophenone with hydroxylamine to form 4-hydroxyacetophenone oxime. This oxime then undergoes a Beckmann rearrangement catalyzed by cyanuric chloride to yield paracetamol. The experiment incorporates several essential organic laboratory techniques, such as reflux, extraction, drying, filtration, rotary evaporation, thin-layer chromatography, and column chromatography, providing students with comprehensive training in organic synthesis. By synthesizing a compound of significant medical and economic value, the experiment demonstrates practical applications of organic synthesis, thereby enhancing student interest in organic chemistry. Additionally, the use of a small molecule organic catalyst for the Beckmann rearrangement deepens students’ understanding of the principles of organic catalysis and the mechanism of the Beckmann rearrangement. [ABSTRACT FROM AUTHOR]

The synthesis of some N-(3-acyloxyacyl)glycines, an interesting class of bioactive gut microbiota metabolites, is described. This procedure involves seven reaction steps using the commercially available Meldrum's acid to obtain highly pure products, in normal or deuterated form. The key point of the synthetic strategy was the use of commendamide t-butyl ester as a synthetic intermediate, a choice that allowed the removal of the protecting group at the end of the synthetic procedure without degrading of the other ester bond present in the molecule. The developed synthetic sequence is particularly simple, uses readily available reagents and involves a limited number of purifications by chromatographic column, with a reduction in the volume of solvent and energy used. [ABSTRACT FROM AUTHOR]

We report on the synthesis of two fluorescent probes which can be activated by β-Galactosidase (β-Gal) enzymes and/or light. The probes contained 2-nitro-4-oxybenzyl and 3-nitro-4-oxybenzyl fragments, with β-Gal residues linked to C-4. We performed the enzymatic and photoactivation of the probes in a cuvette and compared them, prior to the labeling of Vimentin–Halo fusion protein in live cells with overexpressed β-galactosidase. The dye fluorescence afforded the observation of enzyme activity by means of confocal and super-resolution optical microscopy based on stimulated emission depletion (STED). The tracing of enzymatic activity with the retention of activated fluorescent products inside cells was combined with super-resolution imaging as a tool for use in biomedicine and life science. [ABSTRACT FROM AUTHOR]

Using Ni(II) as the catalyst, electron-deficient 3,5-dimethylacryloylpyrazole olefin was reacted with C,N-diarylnitrones alone for 10 min to prepare novel five-member heterocyclic products, 4-3,5-dimethylacryloylpyrazole isoxazolidines with 100% regioselectivity and up to 99% yield. And then, taking these cycloadducts as substrates, six kinds of derivatization reactions, like ring-opening, nucleophilic substitution, addition-elimination and reduction, were studied. Experimental results showed that all kinds of transformations could obtain the target products at a high conversion rate under mild conditions, a finding which provided the basic methods for organic synthesis methodology research based on an isoxazolidine skeleton. [ABSTRACT FROM AUTHOR]

In this paper, we have established an operationally convenient protocol for the rapid construction of polysubstituted methyleneindene and quinoline derivatives under mild conditions. This new synthetic method is achieved through the conversion of acetyl‐substituted methylenecyclopropanes with TsOH ⋅ H2O and ortho‐amino‐substituted methylenecyclopropanes with aromatic aldehyde and TsOH ⋅ H2O, respectively. A variety of transformations of the obtained products was demonstrated. The plausible reaction mechanisms were also proposed. [ABSTRACT FROM AUTHOR]

Horseradish peroxidase (HRP) was immobilized in hybrid calcium alginate-gelatin hydrogel beads by entrapment. Then, organic solubility, metal ion compatibility, pH/temperature studies of the synthesized materials have been carried out. Hybrid beads (Ca-Alg@gel-HRP) were synthesized under optimum synthesis conditions with high yield and specific activity. The synthesized bead size was determined to be approximately 0.29 mm in diameter, hydrogel structure and transparent appearance. Accordingly, the optimum pH of free HRP and Ca-Alg@gel HRP was found to be pH 6 and 5 and the optimum temperature was found to be 40 °C and 60 °C respectively. For all identified metal ions except Fe2+, the Ca-Alg@gel HRP had a higher activity than the free HRP. In the presence of 1 mM Na+, Ca2+, Mg2+, Ba2+, Cu2+, Ni2+, Mn2+, Hg2+ ions, the activity increased by more than 20%. The relative activity was also approximately 153%, 150% and 145% in 2.5 mM chloroform, glycerol and DMF. Free enzyme activity was reduced by more than 30%. The Ca-Alg@gel HRP at room temperature and 4 °C retained most of its activity after 14 days. In cycle 5, it had half the activity. As a conclusion, it may have significant potential in a number of industrial processes, particularly in organic synthesis, because it is tolerant to metal ions and organic solvents and is a cheap, practical and simple immobilization method. [ABSTRACT FROM AUTHOR]

The synthesis of heterocyclic compounds is always one of the most important challenges among synthetic chemists. Pyranopyrazoles are an important class of heterocyclic compounds that are a rich source of biologically important molecules. These derivatives are present as key structures in natural products, bioactive, and biological molecules. So far, many catalytic systems and methods have been reported for the synthesis of these compounds. However, the synthesis of pyranopyrazoles through multicomponent reactions is of great importance, especially from the point of view of green chemistry. During the last decade, the use of magnetic materials as catalysts in the synthesis of organic compounds, especially heterocycles, has created a huge revolution in organic chemistry. The easy and fast separation of magnetic nanocatalysts using only an external magnet is the most important advantage of this type of catalyst, in addition to the complete separation of the catalyst using an external magnetic field, these compounds have the ability to be reused, which leads to cost reduction and savings. This paper covers the catalytic applications of magnetically recoverable nanoparticles for the multicomponent synthesis of pyranopyrazole derivatives. In this review, we discussed on the detials and conditions for the synthesis of pyranopyrazoles as well as presented synthetic mechanisms for their preparation in the presence of nanomagnetic reusable catalysts. [ABSTRACT FROM AUTHOR]

In this research, the preparation of 1,2,4-triazolpyrimidine derivatives was performed by using four component reactions of alkyl 2,4-dioxo-4-(arylamino) butanoate, aldehydes, cyanoguanidine, and hydrazonoyl chloride in the presence of catalytic amounts of Et3N in water at room temperature. In addition, for investigation of antioxidant activity was performed radical trapping by DPPH and reducing the power of ferric ion experiments. As a result, synthesized compounds show excellent radical trapping by DPPH and good reducing ability of ferric ion because of having NH2 group. The current procedure has benefits for instance excellent yield of reaction, green media, and easy separation of product. HIGHLIGHTS: The 1,2,4-triazolpyrimidine ring is an azaaromatic scaffold that can be found in many molecules of biological or pharmaceutical interest. Multicomponent reactions (MCRs) are more interesting type of reaction due to mixing three or more reactants in one-pot and generating one product and economically useful and environmentally secure than to multi-step methods. Carrying out synthesis of organic compounds in water media is very interesting because of water is cheap solvent, more available with high amounts. [ABSTRACT FROM AUTHOR]

The current study focuses on the synthesis of a new organic compound namely, ethyl 2-benzoyl-3,3-bis(methylthio)acrylate, whose structural characterization was performed by single-crystal X-ray analysis. The central portion of the title molecule is planar. The benzoyl and one methylthio group are perpendicular to this plane while the ester and the other methylthio group lie close to the plane. In the crystal, C–H···O hydrogen bonds form chains along the b-axis direction which pack with normal Van der Waals interactions. A Hirshfeld surface (HS) analysis showed H⋅⋅⋅H contacts account for 48.3% of the intermolecular contacts in the crystal packing. The energy framework analysis shows that the contribution of dispersion forces in crystal packing is dominant among other energies. The density functional theory (DFT) study using the 6–31 + G(d,p) basis set provides further insight into reactivity and electronic and optical properties in the gas phase. The HOMO–LUMO gap for the title compound is small which indicates its soft nature and high reactivity. Natural population analysis (NPA) reveals excellent charge transfer and donor–acceptor properties in the compound. The computed global reactivity descriptors also indicate the electronic stability and reactivity of the structure. Molecular electrostatic potential (MESP) map suggested electron-rich sites around the carbonyl (C = O) and oxygen atoms while the corner carbon atoms of the benzene ring are suitable for nucleophilic attack. Furthermore, the significant dipole moment (µo) and polarizability (αo) suggest its high polarizability and optical properties. The measured static first hyperpolarizability (βo) value of 266.74 au indicates its nonlinear optical (NLO) properties. [ABSTRACT FROM AUTHOR]

This study reports the synthesis and computational investigation of two Schiff bases: (E)-N-(4-bromophenyl)-1-(2,6-dichlorophenyl)methanimine (S1) and (E)-4-(((4-bromophenyl)imino)methyl)phenol (S2), with a focus on their potential antibacterial activity. Schiff bases, known for their versatility and application in medicinal chemistry, are synthesized through the condensation reactions of the appropriate aniline with aldehydes. The molecular structures of S1 and S2 were elucidated using basic spectroscopic methods such as Fourier-transform-infrared, ultraviolet-visible as well as ¹H and 13C-NMR, while the purity of the compounds was ascertained using elemental analysis. The stability, chemical reactivities, and electronic properties of S1 and S2 were evaluated using Density Functional Theory (DFT). The energy band gap (ΔE) of S1 and S2 is 2.81 eV and 3.02 eV, respectively, and this infers that S1 is more reactive as well as less stable than S2. The molecular electrostatic potential (MEP) mapping evaluation showed that both S1 and S2 have more of the yellow, green, and red regions than the blue region, signifying that these structures are prone to electrophilic attack. The compounds were screened against two Gram-negative (Klebsiella pneumoniae and Pseudomonas aeruginosa) and one Gram-positive bacteria (Staphylococcus aureus) to evaluate their antibacterial potential. S1 as well as S2 showed antibacterial potential against Staphylococcus aureus and exhibited less or no activity against Klebsiella pneumoniae and Pseudomonas aeruginosa. In silico studies of S1 and S2 against Staphylococcus aureus were carried out, and the outcomes corroborated the experimental findings. Pharmacological evaluation of S1 and S2 showed that both compounds exhibited less violation of Lipinski’s rule of five (Ro5), which makes them less toxic and orally available. [ABSTRACT FROM AUTHOR]

We review the evolution of our understanding of the planetary nebulae phenomenon and their place in the scheme of stellar evolution. The historical steps leading to our current understanding of central star evolution and nebular formation are discussed. Recent optical imaging, X-ray, ultraviolet, infrared, millimeter wave, and radio observations have led to a much more complex picture of the structure of planetary nebulae. The optically bright regions have multiple shell structures (rims, shells, crowns, and haloes), which can be understood within the interacting winds framework. However, the physical mechanism responsible for bipolar and multipolar structures that emerged during the proto-planetary nebulae phase is yet to be identified. Our morphological classifications of planetary nebulae are hampered by the effects of sensitivity, orientation, and field-of-view coverage, and the fraction of bipolar or multipolar nebulae may be much higher than commonly assumed. The optically bright bipolar lobes may represent low-density, ionization-bounded cavities carved out of a neutral envelope by collimated fast winds. Planetary nebulae are sites of active synthesis of complex organic compounds, suggesting that planetary nebulae play a major role in the chemical enrichment of the Galaxy. Possible avenues of future advancement are discussed. [ABSTRACT FROM AUTHOR]

The formation of carbon‐nitrogen bonds holds paramount importance in the realm of synthetic organic chemistry, finding extensive applications in the synthesis of pharmaceuticals, agrochemicals, and organic materials. Herein, we describe a novel EDA complex mediated, metal‐ and photocatalyst‐free, visible‐light‐initiated direct C‐3 amination of biologically important, quinoxalin‐2(1H)‐one moiety. The key to the success lies in the formation of a photoactivated electron donor‐acceptor complex between quinoxalin‐2(1H)‐one and amine, which undergo subsequent electron transfer reaction to effect the desired transformation. A diverse array of 3‐aminoquinoxalin‐2(1H)‐ones were prepared employing this process and the yields are up to 87%. This work represents a significant advancement toward a more environmentally friendly and efficient approach, characterized by mild reaction conditions and a high atom economy. [ABSTRACT FROM AUTHOR]

Hydrogenated pyrans are prevalent structural units existed in many biologically active compounds, capturing the attention of pharmacologists due to their potential therapeutic applications. Among various synthetic routes, the hetero‐Diels‐Alder (HDA) reaction stands out as a common and effective approach. The objective of this study was to employ HDA reaction in conjunction with the dehydrogenative oxidation strategy for saturated ketones to synthesize hydrogenated pyran compounds. Through systematic screening and optimization of reaction conditions, a convenient approach for the synthesis of multi‐substituted 2,3‐dihydro‐4H‐pyran compounds has been developed. Furthermore, a detailed mechanistic investigation has been performed to get a deep understanding of the reaction. [ABSTRACT FROM AUTHOR]

Microorganisms living in the soil of arid rangelands play a key role in maintaining their health. These tiny creatures are agents of organic matter decomposition on which soil fertility depends. Species and quantitative composition of microorganisms is an indicator reflecting the direction of biological processes in the soil. In natural conditions, the ratio of different groups of microorganisms shows whether decomposition or synthesis of organic compounds, including humus, prevails. In agrocenoses where humans use organic and inorganic fertilizers, the study of microorganisms helps to assess the availability of nutrient elements to plants. Analysis of the soil microbial community also allows direct assessment of the effectiveness of biostimulant application, i.e. how well plants assimilate the applied macronutrients. The purpose of our study was to determine the health of the soil by the number and ratio of different groups of microorganisms, to identify whether the processes of decomposition (mineralization) or synthesis (immobilization) of nutrients prevail in the soil and to obtain reliable information on the availability of nutrients for plants. The study of microorganisms in the soil of arid pastures is a valuable tool for assessing their ecological state, as well as for developing more efficient and environmentally friendly farming methods. [ABSTRACT FROM AUTHOR]

Recent years have witnessed the transformative impact from the integration of artificial intelligence with organic and polymer synthesis. This synergy offers innovative and intelligent solutions to a range of classic problems in synthetic chemistry. These exciting advancements include the prediction of molecular property, multi-step retrosynthetic pathway planning, elucidation of the structure-performance relationship of single-step transformation, establishment of the quantitative linkage between polymer structures and their functions, design and optimization of polymerization process, prediction of the structure and sequence of biological macromolecules, as well as automated and intelligent synthesis platforms. Chemists can now explore synthetic chemistry with unprecedented precision and efficiency, creating novel reactions, catalysts, and polymer materials under the data-driven paradigm. Despite these thrilling developments, the field of artificial intelligence (AI) synthetic chemistry is still in its infancy, facing challenges and limitations in terms of data openness, model interpretability, as well as software and hardware support. This review aims to provide an overview of the current progress, key challenges, and future development suggestions in the interdisciplinary field between AI and synthetic chemistry. It is hoped that this overview will offer readers a comprehensive understanding of this emerging field, inspiring and promoting further scientific research and development. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance poses a major threat to global health as the number of efficient antimicrobials decreases and the number of resistant pathogens rises. Our research group has been actively involved in the design of novel antimicrobial drugs. The blueprints of these compounds were azolic heterocycles, particularly thiazole. Starting with oxadiazolines, our research group explored, one by one, the other five-membered heterocycles, developing more or less potent compounds. An overview of this research activity conducted by our research group allowed us to observe an evolution in the methodology used (from inhibition zone diameters to minimal inhibitory concentrations and antibiofilm potential determination) correlated with the design of azole compounds based on results obtained from molecular modeling. The purpose of this review is to present the development of in-house azole compounds with antimicrobial activity, designed over the years by this research group from the departments of Pharmaceutical and Therapeutical Chemistry in Cluj-Napoca. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Axially chiral biaryls represent the most important class of atropisomers, and they widely exist in natural products and biologically active molecules. They also constitute a unique scaffold for chiral ligands and catalysts in organic synthesis. The development of synthetic methods to obtain such chiral compounds has received widespread attention, among which catalytically atroposelective ring‐opening of configurationally labile compounds represents one of the most attractive strategies. Various substrates with strained cyclic structures, such as the renowned Bringmann's lactones, can undergo asymmetric transformation into stable atropisomers. Known advancement primarily relies on metal catalyst combined with well‐designed chiral ligands, the approaches utilizing organocatalysis as a critical resolution strategy are notably scarce. In this study, we disclosed a N‐heterocyclic carbene (NHC)‐catalyzed asymmetric ring‐opening reaction of biaryl lactams via direct atroposelective nucleophilic activation. The optimized bulky carbene catalyst ensures that the reaction can proceed under mild conditions, affording the desired product with good to excellent yields and atroposelectivity. [ABSTRACT FROM AUTHOR]

Designing the catalysts to get high molecular weight polyethylene is an art. The catalysts bearing imine functionality derived from 8‐arylnaphthyl amines are more impressive and attractive in this regard. In this work, we synthesize 2,4‐dibenzhydryl‐8‐(3,5‐dichlorophenyl)naphthalen‐1‐amine to condense with picolinaldehyde, pyridine‐N‐oxide‐2‐carbaldehyde and 3,4‐dibutanone and then subsequently the treatment of resulting ligands with nickel precursors to get the corresponding catalysts. It was hypothesized that 3,5‐dichlorophenyl having extended wings of chlorine atoms along with bulky dibenzhydryl groups can provide good shielding on both apical positions of metal in response to slow down the chain transfer. More interestingly, the polymerization was done in industrially claimed n‐heptane solvent. All the catalysts showed activity in an order of 106, whereas a value of 1.04 × 107 g mol−1 h−1 has been recorded from keto‐imine based Ni‐3 catalyst. All catalysts generates polymer with high molecular weight with maximum value was recorded by Ni‐2 up to 37.4 × 104 g mol−1. Ni‐3 can also incorporate methyl 10‐undecenoate up to 2.6% in polyethylene backbone. [ABSTRACT FROM AUTHOR]

Neighboring group participation, the assistance of non‐conjugated electrons to a reaction center, is a fundamental phenomenon in chemistry. In the framework of nucleophilic substitution reactions, neighboring group participation is known to cause rate acceleration, first order kinetics (SN1), and retention of configuration. The latter phenomenon is a result of double inversion: the first one when the neighboring group displaces the leaving group, and the second when a nucleophile substitutes the neighboring group. This powerful control of stereoretention has been widely used in organic synthesis for more than a century. However, neighboring group participation may also lead to inversion of configuration, a phenomenon which is often overlooked. Herein, we review this unique mode of stereoinversion, dividing the relevant reactions into three classes with the aim to introduce a fresh perspective on the different modes of stereoinversion via neighboring group participation as well as the factors that control this stereochemical outcome. [ABSTRACT FROM AUTHOR]

Retrosynthesis is a crucial task in drug discovery and organic synthesis, where artificial intelligence (AI) is increasingly employed to expedite the process. However, existing approaches employ token-by-token decoding methods to translate target molecule strings into corresponding precursors, exhibiting unsatisfactory performance and limited diversity. As chemical reactions typically induce local molecular changes, reactants and products often overlap significantly. Inspired by this fact, we propose reframing single-step retrosynthesis prediction as a molecular string editing task, iteratively refining target molecule strings to generate precursor compounds. Our proposed approach involves a fragment-based generative editing model that uses explicit sequence editing operations. Additionally, we design an inference module with reposition sampling and sequence augmentation to enhance both prediction accuracy and diversity. Extensive experiments demonstrate that our model generates high-quality and diverse results, achieving superior performance with a promising top-1 accuracy of 60.8% on the standard benchmark dataset USPTO-50 K. Retrosynthesis aims to identify synthesis solutions for compounds in drug discovery. Here, the authors frame it as a molecular string editing task and utilize an iterative string editing model to provide high-quality and diverse solutions. [ABSTRACT FROM AUTHOR]

Catalytic asymmetric synthesis of polysubstituted chiral cyclopropane presents a significant challenge in organic synthesis due to the difficulty in enantioselective control. Here we report a rhodium-catalyzed highly chemo-, regio- and enantioselective hydroformylation of trisubstituted cyclopropenes affording chiral quaternary cyclopropanes. Importantly, the easy made sterically bulky ligand L1 can effectively suppress hydrogenation and decomposition reactions and give quaternary cyclopropanes with high regio- and enantioselectivities for both aryl and alkyl functionalized substrates. Control experiments and computational studies reveal the sterically hindered well-defined chiral pocket instead of the substrates bearing electron-withdrawing diester groups is important for controlling the enantioselectivity and regioselectivity. Scale-up reaction and follow-up diverse transformations are also presented. Density Functional theory (DFT) computations suggest that the regio- and enantio-selectivities originate from the cyclopropene insertion to the Rh-H bond. The high regioselectivity is found to benefit from the presence of more efficient noncovalent interactions (NCIs) manifesting in the form of C–H···Cl, C–H···N, and l.p(Cl)···π contacts. Transition-metal-catalyzed asymmetric hydroformylation represents an atom-economic and clean approach for preparation of chiral aldehydes with high efficiency. Herein, the authors report rhodium-catalyzed highly chemo-, regio- and enantioselective hydroformylation of trisubstituted cyclopropenes affording chiral quaternary cyclopropanes. [ABSTRACT FROM AUTHOR]

In the present era, the concept of green in organic synthesis has a unique and irreplaceable place. Specifically, nanoparticle has gained much more attention due to its various properties related to the concept of green chemistry. In this context, magnetic nanoparticle has been widely used in the organic synthesis over last one decade. Among organic compounds, pyrazole and its scaffolds are recognized as a privileged structure as it represents a promising area for identification of lead structures towards the discovery of new synthetic drug molecules and other valuable candidates. Several commercial drugs such as Sildenafil, Rimonabant, Celecoxib and many other compounds in biological testing and preclinical evaluation, illustrate the wide therapeutic spectrum in this class of drug scaffolds. Accordingly, the magnetic nanoparticles have an irreplaceable place in the synthesis of pyrazole derivatives and it is a green and easy methodology to the organic chemists. The present manuscript represents the assimilation of literature pertaining to green aspects of magnetic nanoparticles for the synthesis of highly diversified and valuable derivatives of pyrazole. [ABSTRACT FROM AUTHOR]

The present study discloses an NIS/PPh3-mediated reductive self-coupling of arylsulfonyl hydrazides to prepare symmetric diaryl disulfides. This methodology has a broad functional-group tolerance and a high scalability. This strategy permits the introduction of sulfonyl hydrazides into the synthesis of symmetrical organic disulfides without the use of a catalyst or base, and symmetrical aromatic disulfides can be prepared in moderate to excellent isolated yields from inexpensive and readily available starting materials. [ABSTRACT FROM AUTHOR]

Chiral γ-keto sulfones are significant structures in both organic synthesis and pharmaceutical chemistry. Although there are many choices for obtaining racemic forms, only a few enantioselective methods have been reported. We have developed a simple way for obtaining chiral γ-keto sulfones in moderate yields and moderate enantiomeric ratios. Readily available sulfinates were directly used as substrates that could be converted into sulfinic acids by treatment with boric acid. The bifunctional catalyst forms a chiral ion pair with the sulfinic acid and controls the enantioselectivity of the sulfonation through hydrogen bonding. [ABSTRACT FROM AUTHOR]

Stereodivergent synthesis of N -heterocycle frameworks bearing 1,3-nonadjacent stereogenic centers through a single transformation remains a high-priority challenge in organic synthesis. Herein, we highlight our recent discovery of stereodivergent access to such useful structural motifs using Pd-catalyzed [4+2] annulation reactions of vinyl benzoxazinaones and seven-membered cyclic N-sulfonyl aldimines. A wide range of N -heterocycles with 1,3-nonadjacent stereogenic centers were obtained in high efficiency and stereodivergency. Importantly, the polarity of solvents was found to play a key role in switching the diastereoselectivity. Furthermore, good enantioselectivities of these reactions were achieved by the employment of commercially available Wingphos as the chiral ligand. [ABSTRACT FROM AUTHOR]

Since their discovery, [2.2]paracyclophane (pCp) and its derivatives have fascinated the scientific community due to their original molecular architecture and unusual electronic behavior. Over the years, significant efforts have been devoted to the development of substituted pCps for a variety of applications in different fields, ranging from organic synthesis and asymmetric catalysis to polymer chemistry and material science. This review describes a series of useful approaches that allow chemists to selectively decorate pCps, control the planar chirality that these molecules can display as soon as they are functionalized, and tune their photophysical behaviors. For each of these aspects of paracyclophane chemistry, selected examples of major advances are presented, and possible directions for future research are outlined. The application of pCp as central core for the development of uncommon 3D luminophores is finally highlighted. Emphasis is placed on the potential use of planar chiral luminescent paracyclophanes as antennas or ligands for the design of multifunctional lanthanide complexes, a quite underdeveloped but highly promising area for future research endeavors. [ABSTRACT FROM AUTHOR]

Metal-catalyzed highly Markovnikov-type selective hydrofunctionalization of terminal alkynes provides a straightforward and atom-economical route to access 1,1-disubstituted alkenes, which have a wide range of applications in organic synthesis. However, the highly Markovnikov-type selective transformations are challenging due to the electronic and steric effects during the addition process. With the development of metal-catalyzed organic synthesis, different metal catalysts have been developed to solve this challenge, especially for platinum group metal catalysts. In this perspective, we review homogeneous metal-catalyzed Markovnikov-type selective hydrofunctionalization of terminal alkynes according to the classified element types as well as reaction mechanisms. Future avenues for investigation are also presented to help expand this exciting field. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have recently seen significant advancements. Large quantities of structurally & functionally oriented COFs with a wide range of applications, such as gas adsorption, catalysis, separation, and drug delivery, have been explored. Recent achievements in this field are primarily focused on advancing synthetic methodologies, with catalysts playing a crucial role in achieving highly crystalline COF materials, particularly those featuring novel linkages and chemistry. A series of reviews have already been published over the last decade, covering the fundamentals, synthesis, and applications of COFs. However, despite the pivotal role that catalysts and auxiliaries play in forming COF materials and adjusting their properties (e.g., crystallinity, porosity, stability, and morphology), limited attention has been devoted to these essential components. In this Critical Review, we mainly focus on the state-of-the-art progress of catalysts and auxiliaries applied to the synthesis of COFs. The catalysts include four categories: acid catalysts, base catalysts, transition-metal catalysts, and other catalysts. The auxiliaries, such as modulators, oxygen, and surfactants, are discussed as well. This is then followed by the description of several specific applications derived from the utilization of catalysts and auxiliaries. Lastly, a perspective on the major challenges and opportunities associated with catalysts and auxiliaries is provided. [ABSTRACT FROM AUTHOR]

The alkylation of arenes is one of the most fundamental transformations in synthetic chemistry and the transition‐metal‐catalyzed direct C−H alkylation represents a straightforward and attractive approach from both atom and step‐economy perspectives. Epoxides, the smallest three‐membered saturated O‐heterocycles that can be easily prepared in racemic or enantioenriched forms, are highly useful building blocks for the synthesis of complex organic molecules. Owing to their inherent high ring‐strain, epoxides readily undergo ring‐opening reactions and have been used as alkylating reagents for C−H alkylation catalyzed by transition metals. This review summarizes recent advances in utilizing epoxides as alkylating reagents in transition‐metal‐catalyzed C−H alkylation as well as their synthetic applications in organic synthesis. [ABSTRACT FROM AUTHOR]