Synthesis Reaction Research Articles

Copper‐Catalyzed γ‐C(sp3)−H Lactamization and Iminolactonization

AbstractDespite extensive efforts to develop γ‐lactamization reactions for pyrrolidinone synthesis using either cyclometallation, C−H insertion, or radical C−H abstraction strategies, γ‐lactamization reactions of aliphatic amides using practical catalysts and common protecting groups remain extremely rare. Herein we report copper‐catalyzed γ‐C(sp3)−H lactamization and iminolactonization of tosyl‐protected aliphatic amides using inexpensive Selectfluor as the sole oxidant. A switchable selectivity of γ‐lactams or γ‐iminolactones can be obtained by using two different sets of reaction conditions. Notably, structurally diverse spiro‐, fused‐, and bridged‐lactams and iminolactones, as well as isoindolinones are accessible by this method. Further derivatization of the γ‐lactam products enables the synthesis of a range of biologically important motifs, including γ‐amino acids, δ‐amino alcohols, and pyrrolidines.

Sustainability of Nonisocyanate Polyurethanes (NIPUs)

This work discusses the synthesis and properties of nonisocyanate polyurethanes (NIPUs) as an environmentally friendly alternative to traditional polyurethanes. NIPUs are made without the use of toxic isocyanates, reducing the environmental impact and safety concerns associated with their production. However, their synthesis reactions often require longer time and more energy to be completed. The sustainability of NIPUs is considered from various angles; the main methods for the synthesis of NIPUs, including rearrangement reactions, transurethanization, and ring-opening polymerization of cyclic carbonates with amines, are examined. Another part focuses on renewable sources, such as vegetable oils, terpenes, tannins, lignins, sugars, and others. The synthesis of waterborne and solvent-free NIPUs is also discussed, as it further reduces the environmental impact by minimizing volatile organic compounds (VOCs) and avoiding the use of harmful solvents. The challenges faced by NIPUs, such as lower molecular weight and higher dispersity compared to traditional polyurethanes, which can affect mechanical properties, were also addressed. Improving the performance of NIPUs to make them more competitive compared to conventional polyurethanes remains a key task in future research.

Shape-Controlled Growth and In Situ Characterization of CdS Nanocrystals via Liquid Cell Transmission Electron Microscopy

Controlling the growth, structure, and shape of CdS nanocrystals is crucial for harnessing their unique physicochemical properties across diverse applications. This control can be achieved by introducing chemical additives into the synthesis reaction mixture. However, precise manipulation of nanocrystal synthesis necessitates a thorough understanding of the formation mechanisms under various chemical conditions, a task that remains challenging. In this study, we employed in situ liquid cell transmission electron microscopy (TEM) to investigate the growth mechanisms of CdS nanocrystals in a reaction solution of cadmium chloride and thiourea, with sodium citrate serving as a structure-directing agent. We observed that CdS nanocrystals evolve through two distinct growth modes: (1) in the absence of sodium citrate, spherical nanocrystals isotropically transform into CdS nanocubes, and (2) in the presence of sodium citrate, cuboid nanocrystals preferentially extend along the {011} direction and anisotropically into CdS triangular nanoplates. Theoretical analysis has confirmed that the adsorption energy of sodium citrate on different crystal facets significantly influences the morphology of the CdS nanocrystals. Our findings not only provide a method for synthesizing CdS nanocrystals based on electron beam induction but also elucidate the intricate nanoscale growth mechanisms, offering insights that could inform the future rational design of nanocrystals with tailored morphologies.

Role of Pyrimidine Derivatives in the Treatment of Cancer

The study of the chemistry of pyrimidines is contributing to the expansion of research into the therapeutic applications of these compounds. In the field of medicinal chemistry, the sheer number of pyrimidine synthesis methods and reactions that are available opens up a world of possibilities. These investigations have been inspired by the fact that pyrimidines can be used as building blocks for a wide variety of compounds that have a physiological effect. The pyrimidine ring and its fused derivatives, which include pyrazolo[3,4-d]pyrimidine, pyrido[2,3-d]pyrimidine, quinazoline, and furo[2,3-d]pyrimidine, have garnered a great deal of attention due to the extensive variety of biological potential that they possess. In addition, fused pyrimidines are considered to be bioisosteres with purines. As a consequence of this, numerous substances, such as pyrimidine and derivatives of fused pyrimidine, have demonstrated promising anticancer potential. Pyrimidine compounds have been shown to possess a number of beneficial qualities, including antibacterial, anticancer, anti-inflammatory, antidiabetic, and analgesic effects. The purpose of this study is to shed light on the anticancer significance of certain fused pyrimidine derivatives and privileged pyrimidines through the use of various types of inhibition. Additionally, the study reveals structure-activity relationships and provides specifics regarding the synthetic compounds that were utilized in the construction of these scaffolds. The hope is that this research will assist medicinal chemists in the development of highly selective pyrimidine anticancer agents. The focus of this review article is on recent research on synthetic pyrimidine compounds that have anticancer effects. Additionally, the paper examines the chemistry and biological activities of pyrimidines.

Synthesis, Characterization, and Hydrogen Evolution Reaction Activity of MoS2 Nanostructures Prepared Using Nonionic Surfactant

Molybdenum disulfide (MoS2) has garnered significant interest as an auspicious catalytic material for the hydrogen evolution reaction (HER). Here, MoS2 nanostructures are synthesized using the hydrothermal method with ammonium molybdate tetrahydrate ((NH4)6Mo7O24∙4H2O) as the Mo source; thioacetamide (CH3CSNH2) as the reducing agent and S source; and nonylphenols 9, nonylphenols 40, and polysorbate 80 as the surfactants. The impact of the different nonionic surfactants on the materials is comprehensively investigated. Moreover, the MoS2 fine structure was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, scanning electron microscopy (SEM), and transmission scanning microscopy (TEM). The HER characteristics of the MoS2 composites are assessed through electrochemical experiments, including linear sweep voltammetry and chronoamperometry measurements. Among the prepared specimens, MoS2/NP 9 exhibits the best electrocatalytic performance in a neutral medium. Furthermore, 240 mV is required to reach the current density of 10 mAcm−2.

Thermodynamic Analysis of Ammonia Synthesis

The paper researches the effect of temperature on ammonia synthesis. The ammonia synthesis reaction is exothermic with a negative entropy change. ∆G < 0 condition is fulfilled at lower temperatures up to 464K (Le Chatelierov principle). It is a constant equilibrium of the ammonia synthesis reaction at lower temperatures, which means that the NH3(g) synthesis reaction is shifted in the direction of NH3(g) formation (higher production of ammonia). The downside of lowering the temperature is that more ammonia is obtained, but the reaction rate slows down. Above 464K, the free enthalpy of the NH3(g) synthesis reaction is greater than zero, so the reaction enters thermodynamically unfavorable conditions. By increasing the reaction temperature, the ammonia yield NH3(g) decreases in the equilibrium mixture. At 400K, it is 0.5127kmol/kmol (51.27%) and at 700K, the synthesis process NH3(g) is practically complete.

The chloroplast ATP synthase redox domain in Chlamydomonas reinhardtii eludes activity regulation for heterotrophic dark metabolism

To maintain CO2 fixation in the Calvin-Benson-Bassham cycle, multistep regulation of the chloroplast ATP synthase (CF1Fo) is crucial to balance the ATP output of photosynthesis with protection of the apparatus. A well-studied mechanism is thiol modulation; a light/dark regulation through reversible cleavage of a disulfide in the CF1Fo γ-subunit. The disulfide hampers ATP synthesis and hydrolysis reactions in dark-adapted CF1Fo from land plants by increasing the required transmembrane electrochemical proton gradient ([Formula: see text]). Here, we show in Chlamydomonas reinhardtii that algal CF1Fo is differently regulated in vivo. A specific hairpin structure in the γ-subunit redox domain disconnects activity regulation from disulfide formation in the dark. Electrochromic shift measurements suggested that the hairpin kept wild-type CF1Fo active, whereas the enzyme was switched off in algal mutant cells expressing a plant-like hairpin structure. The hairpin segment swap resulted in an elevated [Formula: see text] threshold to activate plant-like CF1Fo, increased by ~1.4 photosystem (PS) I charge separations. The resulting dark-equilibrated [Formula: see text] dropped in the mutants by ~2.7 PSI charge separation equivalents. Photobioreactor experiments showed no phenotypes in autotrophic aerated mutant cultures. In contrast, chlorophyll fluorescence measurements under heterotrophic dark conditions point to an altered dark metabolism in cells with the plant-like CF1Fo as the result of bioenergetic deviations from wild-type. Our results suggest that the lifestyle of C. reinhardtii requires a specific CF1Fo dark regulation that partakes in metabolic coupling between the chloroplast and acetate-fueled mitochondria.

Mechanistic insight into accelerating of light olefin products by surface OH* group on the Fe5C2 catalyst

The conversion of CO2 into high-value-added chemicals via the Fischer-Tropsch Synthesis (FTS) reaction has gathered a lot of attention. The surface oxygenation environment is a significant factor affecting performance of the catalyst. In this work, spin-polarized density-functional theory calculations have been used to investigate the OH* modulation mechanism on CO2 hydrogenation to generate C1 and C2 species. On the pure Fe5C2(510) surface, CH4 is formed through the hydrogenation of dissociated carbon by CO2 activation. At low OH* coverage, the C–C coupling reactions are dramatically promoted compared to methane formation. In addition, CO2 hydrogenation reactions are facilitated by the OH* species, indicating a high activatity and C2+ selectivity. At high OH* coverage, C2 products preferentially form through the CsH2-CdH2* intermediates, contributing to the high selectivity of light olefin products. The results demonstrate that maintaining the surface environment with OH* could be an indispensable measure to obtain the target product in the iron-based CO2 Fischer-Tropsch synthesis system.

Synthesis of ZrW2O8–ZrC composite powders by solid‐state exothermic oxidation reaction of ZrC and WO3 powders

AbstractIn this work, ZrW2O8‐coated ZrC composite powders are synthesized by solid‐state reaction method using ZrC and WO3 powders. Thermodynamic analysis shows that when the molar ratio of ZrC to WO3 is larger than 5:4, ZrW2O8 cannot be synthesized by solid reaction of ZrC and WO3. The favorable molar ratio of ZrC to WO3 for solid reaction synthesis ZrW2O8 is 1:2. After reacted below 800°C for 8 hours, only ZrC in the ZrC and WO3 mixture powders partially reacts with oxygen to form ZrO2. And there is no detectable reaction between WO3 and the formed ZrO2 to produce ZrW2O8. ZrC and WO3 can synthesize ZrW2O8 at 900°C. ZrW2O8‐coated ZrC composite powders can be synthesized using powder mixtures with molar ratio of ZrC:WO3 = 1:1.7 and ZrC:WO3 = 1:1.9 after heat treatment at 1000°C for 4 hours. The synthesized ZrW2O8‐coated ZrC particles show cubic shape with obvious particles growth. The exothermic oxidation reaction of ZrC leads to a significant increase in local temperature, which is believed to trigger partial reaction between ZrO2 and WO3 to form ZrW2O8.

Towards Photothermal Acid Catalysts Using Eco-Sustainable Sulfonated Carbon Nanoparticles—Part II: Thermal and Photothermal Catalysis of Biodiesel Synthesis

The main goal of this work is to evaluate the ability of sulfonated carbon nanoparticles (SCNs) to induce photothermal catalysis of the biodiesel synthesis reaction (transesterification of natural triglycerides (TGs) with alcohols). Carbon nanoparticles (CNs) are produced by the carbonization of cross-linked resin nanoparticles (RNs). The RNs are produced by condensation of a phenol (resorcinol or natural tannin) with formaldehyde under ammonia catalysis (Stober method). The method produces nanoparticles, which are carbonized into carbon nanoparticles (CNs). The illumination of CNs increases the temperature proportionally (linear) to the nanoparticle concentration and exposure time (with saturation). Solid acid catalysts are made by heating in concentrated sulfuric acid (SEAr sulfonation). The application of either light or a catalyst (SCNs) (at 25 °C) induced low conversions (<10%) for the esterification reaction of acetic acid with bioethanol. In contrast, the illumination of the reaction medium containing SCNs induced high conversions (>75%). In the case of biodiesel synthesis (transesterification of sunflower oil with bioethanol), conversions greater than 40% were observed only when light and the catalyst (SCNs) were applied simultaneously. Therefore, it is possible to use sulfonated carbon nanoparticles as photothermally activated catalysts for Fischer esterification and triglyceride transesterification (biodiesel synthesis).

Theoretical Analysis of Multi-conformational Transition States and Diastereo/Regio-selective Reactions in Natural Product Synthesis

Theoretical Analysis of Multi-conformational Transition States and Diastereo/Regio-selective Reactions in Natural Product Synthesis

Enhanced electrocatalytic C[sbnd]H amination of toluene via tailored interfacial microenvironment

Electrocatalytic CH amination of hydrocarbons is a promising avenue for the synthesis of high-value CN compounds. However, efficient activation of CH bonds remains a significant challenge in electrocatalytic CN coupling. Herein, we present a novel strategy to enhance the electrocatalytic conversion of toluene to N-benzylacetamide through a Ritter–type reaction by engineering a hydrophobic electrode–electrolyte interface using polytetrafluoroethylene (PTFE)-coated carbon paper (CP). The hydrophobic CP-based electrode exhibited a superior N-benzylacetamide productivity of 1860.9 mmol m−2h−1 and a substantially higher Faradaic efficiency (FE) of 70.1 % compared to pure CP (41.5 %). Experimental results and density functional theory (DFT) calculations reveal that the PTFE coating promotes toluene adsorption and efficiently lowers the energy barrier for toluene dehydrogenation. Additionally, the hydrophobic interface effectively hinders water adsorption on the electrode, suppressing the competitive water oxidation reaction. This study underscores the crucial role of interfacial engineering in optimizing electrocatalytic CN coupling reactions for the sustainable synthesis of high-value amide compounds.

Semisynthetic p-Coumaric Acid Derivatives as Lead Dual Inhibitors Against DPP-IV and GSK-3β for Antidiabetic Therapy.

Type 2 diabetes mellitus is a dramatically increasing global public health challenge. The prevalence is projected almost double, from 194 million in 2003 to 333 million in 2025 with type 2 diabetes mellitus representing approximately 90%-95% of cases. Dual inhibitors for antidiabetic targets is still novel and promising strategy for discovery of more effective therapies. Ester and triazole derivatives of p-coumaric acid were obtained from Williamson synthesis and Microwave-assisted click reaction, respectively. Chemical structures were finely characterized through IR, 1H, and 13C NMR and HRMS. They were tested for their dual inhibitory activity against GSK-3β kinase and DPP-IV. The complexes resulting from docking were used for all-atom molecular dynamics simulations, including the enzymes in the apo form, using the GROMACS 2022.3. Two inhibitors 2 and 5 demonstrated promising inhibition at low and submicromolar against both proteins. Molecular Dynamic simulations revealed that the binding pattern of the control inhibitors were reproduced by p-coumaric acid derivatives 2 and 5 with crucial interactions involving the same residues. The p-coumaric skeleton can be considered as a promising core for GSK-3β kinase and DPP-IV dual inhibitors.

Design, Synthesis, and Screening for Anticancer and Antimicrobial Activities of New Dihydropyridine‐Anchored Pyrazole and 1,2,3‐Triazole Hybrids

AbstractTwo new libraries of diethyl and dimethyl dihydropyridines‐based pyrazole and 1,2,3‐triazole hybrids (7a–g and 7h–n) were synthesized via a series of reactions involving click chemistry, pyrazole synthesis, and multicomponent reaction. All the new compounds were screened for their in vitro anticancer activity and antimicrobial activities. The 4‐chloro substituted analogue (7i) in dimethyl ester series showed an excellent activity against all three, namely, human breast adenocarcinoma (MCF‐7), human cervical cancer (HeLa), and human breast cancer triple‐positive (BT‐474) cell lines with IC50 values of 0.119 ± 0.58 µM, 0.135 ± 0.13 µM, and 0.163 ± 0.31 µM, respectively compared to abemaciclib. Molecular docking studies performed on the best active compound 7i against crystal structure of CDK6 revealed its best binding score and interactions. Additionally, these libraries were screened for their antimicrobial activities and determined their MIC. Compounds with ─Cl (7b), ─OMe (7d), ─Me (7a) substitution, and without substitution (7e) significantly showed better MIC values in comparison to ampicillin and nystatin.

Phenazine embellished carbon platelets via cascade reaction synthesis serving as fire shield for cotton fabrics.

Phenazine embellished carbon platelets via cascade reaction synthesis serving as fire shield for cotton fabrics.

Sodium Copper Chlorophyllin: A Sustainable Bioinspired Catalyst for the Aerobic Oxidative Synthesis of Nitrogen Heterocycles and the Oxidative Cyanation of Tertiary Amines

AbstractA remarkably simple and straightforward protocol has been reported showcasing sodium copper chlorophyllin (SCC) as an eco‐friendly, bioinspired catalyst for the aerobic oxidative synthesis of pharmaceutically prevalent nitrogen‐containing heterocycles, such as benzimidazoles and quinoxalines. This reaction was performed in green solvent water, using the green oxidant, molecular oxygen. SCC displayed exceptional efficiency, congruent with the prevailing metal/non‐metal‐based catalyst regime without requiring additives. The SCC catalyst exhibited excellent recyclability upto three cycles for the benzimidazole synthesis reaction. This benign strategy was successfully applied in synthesizing a bioactive quinoxaline i. e., Tyrphostin AG1296, a promising candidate for melanoma treatment. The catalytic activity of SCC was explored for the synthesis of another privileged moiety i. e., α‐aminonitriles, via the α‐cyanation of tertiary amines under oxidative conditions. This reaction progressed with a mild, easy‐to‐use, convenient cyanide source, such as ethyl cyanoformate, and a green and attractive solvent, such as methanol, precluding acidic media. SCC catalyst was efficiently recycled upto three cycles for the α‐aminonitriles synthesis. Overall, the utility of a biodegradable, robust catalyst such as SCC, eco‐friendly solvents such as water and methanol, green oxidants such as O2, and mild reaction conditions, devoid of acidic additives, renders the present work viable for academic and industrial research.

Synthesis of Stearyl Alcohol/Polyethylene Glycol Hybrids as Water-Repellent Finishes for Cotton/Polyester Blended Fabric

AbstractNowadays, developing and innovation of new finishing agents that are cost effective, efficient, durable, and safe for the consumer as well as the environment are greatly required by the textile manufactures. In that concern, new stearyl alcohol/polyethylene glycol (SA/PEG) hybrids were synthesized, characterized, and applied as textile finishes to impart cotton/polyester fabric with water repellency. Such hybrids were synthesized by reaction of SA with PEG of molecular weight 1000 or 4000 Da in the presence of ammonium persulfate (APS) as initiator. The optimum conditions of the synthesis reaction are: APS/PEG, 20%; PEG/SA, 15%; reaction temperature, 80 °C and reaction time, 45 min. The synthesized hybrids are self-water dispersible that form oil-in-water stable emulsions. The results indicated that treating cotton/polyester fabric with easy-care finishing formulation containing 60 g/L of dimethyloldihydroxyethylene urea as a cross-linker, and 60 g/L of any of such hybrids emulsions imparts the treated fabric with water repellency, softness, and stiffness properties. Moreover, increasing the PEG molecular weight from 1000 to 4000 Da leads to a reduction in extents of softness and contact angle along with an enhancement in stiffness of treated fabric. Furthermore, the prepared hybrids emulsions-treated fabric samples are durable up to five washing cycles. The FTIR analysis confirmed the chemical structure of the synthesized SA/PEG1000 hybrid. The transmission electron microscope (TEM) revealed that the particles size of SA/PEG4000 hybrid emulsion is in the range of 34–70 nm and reaches to 185 nm in case of the SA/PEG4000 hybrid emulsion. The surface of SA/PEG1000 hybrid emulsion-treated fabric was characterized via scanning electron microscope (SEM).

Copper-Catalyzed γ-C(sp3)-H Lactamization and Iminolactonization.

Despite extensive efforts to develop γ-lactamization reactions for pyrrolidinone synthesis using either cyclometallation, C-H insertion, or radical C-H abstraction strategies, γ-lactamization reactions of aliphatic amides using practical catalysts and common protecting groups remain extremely rare. Herein we report copper-catalyzed γ-C(sp3)-H lactamization and iminolactonization of tosyl-protected aliphatic amides using inexpensive Selectfluor as the sole oxidant. A switchable selectivity of γ-Lactams or γ-iminolactones can be obtained by using two different sets of reaction conditions. Notably, structurally diverse spiro-, fused-, and bridged-lactams and iminolactones, as well as isoindolinones are accessible by this method. Further derivatization of the γ-lactam products enables the synthesis of a range of biologically important motifs, including γ-amino acids, δ-amino alcohols, and pyrrolidines.

Hybrid Metal Catalysts as Valuable Tools in Organic Synthesis: An Overview of the Recent Advances in Asymmetric C─C Bond Formation Reactions.

Carbon-carbon bond formation represents a key reaction in organic synthesis, resulting in paramount importance for constructing the carbon backbone of organic molecules. However, traditional metal-based catalysis, despite its advantages, often struggles with issues related to efficiency, selectivity, and sustainability. On the other hand, while biocatalysis offers superior selectivity due to an extraordinary recognition process of the substrate, the scope of its applicable reactions remains somewhat limited. In this context, Artificial Metalloenzymes (ArMs) and Metallo Peptides (MPs) offer a promising and not fully explored solution, merging the two fields of transition metal catalysis and biotransformations, by inserting a catalytically active metal cofactor into a customizable protein scaffold or coordinating the metal ion directly to a short and tunable amino acid (Aa) sequence, respectively. As a result, these hybrid catalysts have gained attention as valuable tools for challenging catalytic transformations, providing systems with new-to-nature properties in organic synthesis. This review offers an overview of recent advances in the development of ArMs and MPs, focusing on their application in the asymmetric carbon-carbon bond-forming reactions, such as carbene insertion, Michael additions, Friedel-Crafts and cross-coupling reactions, and cyclopropanation, underscoring the versatility of these systems in synthesizing biologically relevant compounds.

Capture and catalytic conversion of CO2 from marine and offshore applications – A review

Abstract This contribution examines recent advances in modeling fluid dynamics and capture/conversion of CO2 from marine and offshore applications in packed-bed columns/trickle-bed reactors subjected to static inclination, externally-induced rolling and heaving motions. Breaking the axial symmetry of the two-phase flow once the packed bed system is tilted results in a significant decrease in process performance, the extent of which is determined by the magnitude of the tilt and the column/reactor diameter. Only the conversion of CO2 from marine engine emissions on-board large cargo ships via catalytic cycloaddition of CO2 to styrene oxide in multiphase large-diameter trickle-bed reactors increases slightly with increasing reactor inclination. Under the externally induced column/reactor oscillations, CO2 capture/conversion performance shifts toward the steady-state solution of the vertical column/reactor as the asymmetry between the two inclined positions decreases. Oscillating (between two inclined symmetrical positions) and heaving packed-bed columns/trickle-bed reactors generate an oscillating performance around the steady-state solution of the vertical static position, which is driven by the amplitude and period of the angular and heaving motions via the continuous evolution of the intensity of the reverse secondary flow and by the magnitude of the reactor/column diameter. The catalytic conversion of CO2 captured from marine emissions via an integrated process coupling reverse water-gas shift reaction and methanol synthesis in a fixed-bed reactors network system shows a remarkable enhancement with the addition of H2O adsorbent to the reaction systems in the sorption-enhanced process periods.