Статті в журналах: "Organic synthesis, Catalysis, and methodology development"

1

De Vreese, Rob, and Matthias D’hooghe. "N-Heterocyclic carbene/Brønsted acid cooperative catalysis as a powerful tool in organic synthesis." Beilstein Journal of Organic Chemistry 8 (March 14, 2012): 398–402. http://dx.doi.org/10.3762/bjoc.8.43.

Повний текст джерела

Анотація:

The interplay between metals and N-heterocyclic carbenes (NHCs) has provided a window of opportunities for the development of novel catalytic strategies within the past few years. The recent successful combination of Brønsted acids with NHCs has added a new dimension to the field of cooperative catalysis, enabling the stereoselective synthesis of functionalized pyrrolidin-2-ones as valuable scaffolds in heterocyclic chemistry. This Commentary will briefly highlight the concept of N-heterocyclic carbene/Brønsted acid cooperative catalysis as a new and powerful methodology in organic chemistry.

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Dzieszkowski, Krzysztof, and Zbigniew Rafiński. "N-Heterocyclic Carbene Catalysis under Oxidizing Conditions." Catalysts 8, no. 11 (November 16, 2018): 549. http://dx.doi.org/10.3390/catal8110549.

Повний текст джерела

Анотація:

N-heterocyclic carbene organocatalysis under oxidizing conditions provides a vast range of various synthetic procedures via diverse mechanisms. The available catalysts, bases, oxidants, and oxidizing methods afford numerous opportunities for developing this branch of organocatalysis. Furthermore, implementation of tandem reactions and cooperative catalysis in the described methodology significantly expands the possibilities of modern organic chemistry. This approach allows the synthesis of different structurally complex and often enantiomerically enriched substances, which can be interesting in terms of biological activity and natural product synthesis. Many esters, amides, thioesters, lactams, lactones, and other cyclic compounds obtained in oxidative or oxygenative reactions promoted by N-heterocyclic carbenes can be interesting precursors in advanced organic synthesis. Sophistication and broad applicability prove that the described synthetic approaches are exceptionally worthy of further development.

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Lübken, Dennis, Marius Saxarra, and Markus Kalesse. "Tris(acetylacetonato) Iron(III): Recent Developments and Synthetic Applications." Synthesis 51, no. 01 (November 27, 2018): 161–77. http://dx.doi.org/10.1055/s-0037-1610393.

Повний текст джерела

Анотація:

Tris(acetylacetonato) iron(III) [Fe(acac)3] is an indispensable reagent in synthetic chemistry. Its applications range from hydrogen atom transfer to cross-coupling reactions and to use as a Lewis acid. Consequently, the exceptional utility of Fe(acac)3 has been demonstrated in several total syntheses. This short review summarizes the applications of Fe(acac)3 in methodology and catalysis and highlights its use for the synthesis of medicinally relevant structures and in natural product syntheses.1 Introduction2 Hydrogen Atom Transfer (HAT)3 Oxidations and Radical Transformations4 Synthesis and Use of Alkynes and Allenes5 Cross-Couplings and Cycloisomerizations6 Borylations7 Miscellaneous Reactions8 Conclusions

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Biswas, Swapan Kumar. "Recent development of Silver-catalyzed Oxo- and Aza cyclization." International Journal of Experimental Research and Review 26 (December 30, 2021): 90–98. http://dx.doi.org/10.52756/ijerr.2021.v26.007.

Повний текст джерела

Анотація:

This article addresses new developments in silver-catalyzed cyclization processes, resulting in the formation of carbocyclic or heterocyclic rings. Some essential techniques in organic chemistry include silver-catalyzed reactions. In addition, silver catalysts have been emerged as a novel catalysis in the last two decades. In these sequences, preparations of oxygen and nitrogen-containing heterocyclic compounds emerge as the most important development of new methodology. Silver catalysts exhibit significant reactivity in mild conditions in contrast to other transition metals such as copper, lead, zinc, ruthenium, gallium, indium, and niobium. These developments have lots of scientific attention due to their potential to synthesise of heterocyclic compounds in medicinal and agrochemical use. This current literature review summarises several silver-catalyzed oxo and aza-cyclization processes using readily available starting materials.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Koskinen, Ari M. P. "Chirospecific synthesis: Catalysis and chiral pool hand in hand." Pure and Applied Chemistry 83, no. 3 (January 16, 2011): 435–43. http://dx.doi.org/10.1351/pac-con-10-10-09.

Повний текст джерела

Анотація:

Nature provides us with a wonderful pool of enantiopure starting materials for synthesis: amino acids, sugars, and many (but not all!) terpenes can be isolated even in large quantities in an uncompromised 100 % ee. Vicinal amino alcohols constitute a versatile group of organic structures; they are, in principle, available in enantiopure form from the chiral pool compounds or through chiral catalysis; they are potent intermediates for the synthesis of natural products and medicinally/biologically active compounds, and they provide a highly desirable scaffold for the construction of ligands for metals as well as organocatalysts. These new techniques will open up valuable new possibilities for the invention of new technologies for chemical synthesis, the desired course of chemical discoveries for the future. A robust entry to enantiopure vicinal amino alcohols from inexpensive naturally occurring amino acids has therefore become a key challenge for our endeavors in the development of methodology.

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Yeung, Ying-Yeung. "Cluster Preface: Organosulfur and Organoselenium Compounds in Catalysis." Synlett 30, no. 14 (August 19, 2019): 1643–45. http://dx.doi.org/10.1055/s-0039-1690021.

Повний текст джерела

Анотація:

Ying-Yeung Yeung received his B.Sc. (2001) at The Chinese University of Hong Kong. He continued his graduate research at the same university under the supervision of Prof. Tony K. M. Shing. After four years (2001–2005) of research dedicated toward natural product synthesis, he moved to the USA to conduct postdoctoral research with Prof. E. J. Corey at Harvard University (2005–2008). In 2008, he joined the National University of Singapore, Department of Chemistry. In 2015, he moved to The Chinese University of Hong Kong as an associate professor. He has been the department chairman (since 2016) and a full professor (since 2019). His research interests include asymmetric catalysis, green oxidation, and methodology development.

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Cortón, Pablo, Paula Novo, Vanesa López-Sobrado, Marcos D. García, Carlos Peinador, and Elena Pazos. "Solid-Phase Zincke Reaction for the Synthesis of Peptide-4,4′-bipyridinium Conjugates." Synthesis 52, no. 04 (July 30, 2019): 537–43. http://dx.doi.org/10.1055/s-0039-1690016.

Повний текст джерела

Анотація:

We present herein the development of a new synthetic strategy for the conjugation of 4,4′-bipyridinium derivatives into peptide scaffolds. The methodology, based on the development of a solid-phase version of the Zincke reaction between activated pyridinium salts and amines, is able to produce the desired conjugates in a straightforward fashion, with the bipyridinium units attached at the N-terminus of peptides or at Lys side chains of N-terminal acetylated peptides.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Kim, Nari, Calvin C. H. Cheng, and M. Cynthia Goh. "Universal aqueous synthesis of ultra-small polymer-templated nanoparticles: synthesis optimization methodology for counterion-collapsed poly(acrylic acid)." Canadian Journal of Chemistry 96, no. 1 (January 2018): 44–50. http://dx.doi.org/10.1139/cjc-2017-0444.

Повний текст джерела

Анотація:

A long polyelectrolyte chain collapses into a nano-sized particle upon the addition of counterions under appropriate solution conditions. This phenomenon forms the basis for a simple universal method for aqueous synthesis of ultra-small (<10 nm) metal, metal oxide, and other types of nanoparticles in the following manner: the counterion-collapsed polyelectrolyte chains are made stable by crosslinking, effectively trapping the counterions, which are subsequently chemically modified, to form metal nanoparticles via reduction or metal oxides nanoparticles via oxidation, within the collapsed polymer nanoparticle. This highly versatile platform methodology can be applied to almost any polyelectrolyte–counterion pair, making possible the rapid development of syntheses of different nanoparticles within the same chemical environment. Using poly(acrylic acid) as a model system, a methodology for the optimization of conditions for the polyelectrolyte collapse by various mono- and multi-valent metal cations is developed. The optimal counterion concentration did not correlate with ionic strength and metal ion valency and was highly variable from system to system. By monitoring the polyelectrolyte conformation using viscosity and turbidity measurements, the appropriate metal ion concentration for each nanoparticle system was determined.

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Feng, Liang, Kun-Yu Wang, Xiu-Liang Lv, Tian-Hao Yan, and Hong-Cai Zhou. "Hierarchically porous metal–organic frameworks: synthetic strategies and applications." National Science Review 7, no. 11 (November 5, 2019): 1743–58. http://dx.doi.org/10.1093/nsr/nwz170.

Повний текст джерела

Анотація:

Abstract Despite numerous advantages, applications of conventional microporous metal–organic frameworks (MOFs) are hampered by their limited pore sizes, such as in heterogeneous catalysis and guest delivery, which usually involve large molecules. Construction of hierarchically porous MOFs (HP-MOFs) is vital to achieve the controllable augmentation of MOF pore size to mesopores or even macropores, which can enhance the diffusion kinetics of guests and improve the storage capacity. This review article focuses on recent advances in the methodology of HP-MOF synthesis, covering preparation of HP-MOFs with intrinsic hierarchical pores, and modulated, templated and template-free synthetic strategies for HP-MOFs. The key factors which affect the formation of HP-MOF architectures are summarized and discussed, followed by a brief review of their applications in heterogeneous catalysis and guest encapsulation. Overall, this review presents a roadmap that will guide the future design and development of HP-MOF materials with molecular precision and mesoscopic complexity.

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Scheffer, John R. "2000 Alfred Bader Award LectureIn the footsteps of Pasteur: asymmetric induction in the photochemistry of crystalline ammonium carboxylate salts." Canadian Journal of Chemistry 79, no. 4 (April 1, 2001): 349–57. http://dx.doi.org/10.1139/v01-060.

Повний текст джерела

Анотація:

This review describes the development of a new, synthetically useful method of asymmetric synthesis in organic photochemistry. Similar in many ways to the Pasteur procedure for resolving racemic carboxylic acids and organic amines, the method relies on the use of crystalline organic salts in which the enantioselectivity of a photochemical reaction of an achiral organic ion (for example, a carboxylate anion) is governed in the solid state by the presence of an optically pure counterion (for example, an optically active ammonium ion). Such optically pure counterions are termed ionic chiral auxiliaries. Salts containing ionic chiral auxiliaries are required to crystallize in chiral space groups, which provide the asymmetric environment necessary for chiral induction. Using this methodology, we have obtained near-quantitative optical yields in a wide variety of photochemical reactions.Key words: photochemistry, solid state, chiral auxiliaries, asymmetric synthesis, crystal structurereactivity relationships.

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Kanwal, Iram, Aqsa Mujahid, Nasir Rasool, Komal Rizwan, Ayesha Malik, Gulraiz Ahmad, Syed Adnan Ali Shah, Umer Rashid, and Nadiah Mad Nasir. "Palladium and Copper Catalyzed Sonogashira cross Coupling an Excellent Methodology for C-C Bond Formation over 17 Years: A Review." Catalysts 10, no. 4 (April 20, 2020): 443. http://dx.doi.org/10.3390/catal10040443.

Повний текст джерела

Анотація:

Sonogashira coupling involves coupling of vinyl/aryl halides with terminal acetylenes catalyzed by transition metals, especially palladium and copper. This is a well known reaction in organic synthesis and plays a role in sp2-sp C-C bond formations. This cross coupling was used in synthesis of natural products, biologically active molecules, heterocycles, dendrimers, conjugated polymers and organic complexes. This review paper focuses on developments in the palladium and copper catalyzed Sonogashira cross coupling achieved in recent years concerning substrates, different catalyst systems and reaction conditions.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Wrzeszcz, Zuzanna, and Renata Siedlecka. "Heteroaromatic N-Oxides in Asymmetric Catalysis: A Review." Molecules 25, no. 2 (January 14, 2020): 330. http://dx.doi.org/10.3390/molecules25020330.

Повний текст джерела

Анотація:

An increasing interest in the synthesis and use of optically active pyridine N-oxides as chiral controllers for asymmetric reactions has been observed in the last few years. Chiral heteroaromatic N-oxides can work as powerful electron-pair donors, providing suitable electronic environments in the transition state formed within the reaction. The nucleophilicity of the oxygen atom in N-oxides, coupled with a high affinity of silicon to oxygen, represent ideal properties for the development of synthetic methodology based on nucleophilic activation of organosilicon reagents. The application of chiral N-oxides as efficient organocatalysts in allylation, propargylation, allenylation, and ring-opening of meso-epoxides, as well as chiral ligands for metal complexes catalyzing Michael addition or nitroaldol reaction, can also be found in the literature. This review deals with stereoselective applications of N-oxides, and how the differentiating properties are correlated with their structure. It contains more recent results, covering approximately the last ten years. All the reported examples have been divided into five classes, according to the chirality elements present in their basic molecular frameworks.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

McMurray, Lindsay, Thomas M. McGuire, and Rachel L. Howells. "Recent Advances in Photocatalytic Decarboxylative Coupling Reactions in Medicinal Chemistry." Synthesis 52, no. 12 (March 9, 2020): 1719–37. http://dx.doi.org/10.1055/s-0039-1690843.

Повний текст джерела

Анотація:

This review covers recent advances in decarboxylative photocatalysis applicable to the medicinal chemist. The review is not intended to be exhaustive, but instead is focussed on transformations that could be useful in the synthesis of drug-like compounds in order to highlight the utility of this methodology in the development of new pharmaceutical candidates.1 Introduction2 C–C Bond Formation3 C–N and C–O Bond Formation4 Fluorination and Trifluoromethylation5 Hydrodecarboxylation6 Protein Functionalisation7 Conclusion

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Kwon, Kitae, R. Thomas Simons, Meganathan Nandakumar, and Jennifer L. Roizen. "Strategies to Generate Nitrogen-centered Radicals That May Rely on Photoredox Catalysis: Development in Reaction Methodology and Applications in Organic Synthesis." Chemical Reviews 122, no. 2 (October 8, 2021): 2353–428. http://dx.doi.org/10.1021/acs.chemrev.1c00444.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Albert-Soriano, María, and Isidro M. Pastor. "N,N-Diethyl-3-methylbenzamide." Molbank 2022, no. 3 (June 25, 2022): M1395. http://dx.doi.org/10.3390/m1395.

Повний текст джерела

Анотація:

The development of new techniques for the preparation of organic compounds is important, with catalytic processes being key to this innovation. The development of copper-based metal-organic frameworks to promote oxidative couplings has allowed the synthesis of amides in a very effective manner. This methodology has been successfully applied to the unique preparation of the bioactive compound N,N-diethyl-3-methylbenzamide, with excellent performance (>99% conversion and 95% yield of pure isolated product) on a preparative scale. The described procedure can be classified as an excellent synthesis (EcoScale) considering environmental and economic factors based on different “green metrics” (atom economy, reaction mass efficiency, materials recovery factor, stoichiometric factor, E-factor).

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Bortolami, Martina, Ingrid Izabela Bogles, Cecilia Bombelli, Fabiana Pandolfi, Marta Feroci, and Fabrizio Vetica. "Electrochemical Bottom-Up Synthesis of Chiral Carbon Dots from L-Proline and Their Application as Nano-Organocatalysts in a Stereoselective Aldol Reaction." Molecules 27, no. 16 (August 12, 2022): 5150. http://dx.doi.org/10.3390/molecules27165150.

Повний текст джерела

Анотація:

Chirality is undoubtedly a fundamental property of nature since the different interactions of optically active molecules in a chiral environment are essential for numerous applications. Thus, in the field of asymmetric synthesis, the search for efficient, sustainable, cost-effective and recyclable chiral catalysts is still the main challenge in organic chemistry. The field of carbon dots (CDs) has experienced tremendous development in the last 15 years, including their applications as achiral catalysts. Thus, understanding the implications of chirality in CDs chemistry could be of utmost importance to achieving sustainable and biocompatible chiral nanocatalysts. An efficient and cost-effective electrochemical synthetic methodology for the synthesis of L-Proline-based chiral carbon dots (CCDs) and EtOH-derived L-Proline-based chiral carbon dots (CCDs) is herein reported. The electrochemical set-up and reaction conditions have been thoroughly optimised and their effects on CCDs size, photoluminescence, as well as catalytic activity have been investigated. The obtained CCDs have been successfully employed to catalyze an asymmetric aldol reaction, showing excellent results in terms of yield, diastereo- and enantioselectivity. Moreover, the sustainable nature of the CCDs was demonstrated by recycling the catalysts for up to 3 cycles without any loss of reactivity or stereoselectivity.

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Camp, Jason, Thomas Bousfield, Jay Dunsford, James Adams, Joshua Britton, Michael Fay, and Athanasios Angelis-Dimakis. "Dehydrative Cross-Coupling of 1-Phenylethanol Catalysed by Palladium Nanoparticles Formed in situ Under Acidic Conditions." Synthesis 50, no. 19 (August 27, 2018): 3862–74. http://dx.doi.org/10.1055/s-0037-1610246.

Повний текст джерела

Анотація:

A dehydrative cross-coupling of 1-phenylethanol catalysed by sugar derived, in situ formed palladium(0) nanoparticles under acidic conditions is realised. The acidic conditions allow for use of alcohols as a feedstock in metal-mediated coupling reactions via their in situ dehydration and subsequent cross-coupling. Extensive analysis of the size and morphology of the palladium nanoparticles formed in situ showed that the zero-valent metal was surrounded by hydrophilic hydroxyl groups. EDX-TEM imaging studies using a prototype silicon drift detector provided insight into the problematic role of molecular oxygen in the system. This increased understanding of the catalyst deactivation allowed for the development of the cross-coupling methodology. A 250-12,000 fold increase in molar efficiency was observed when compared to related two-step protocols that use alternative feedstocks for the palladium-mediated synthesis of stilbenes. This work opens up a new research area in which the active catalyst is formed, stabilised and regenerated by a renewable sugar.

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Szadkowska, Anna, Cezary Samojłowicz, and Karol Grela. "Enhancement of ruthenium-catalyzed olefin metathesis reactions: Searching for new catalyst or new reaction conditions?" Pure and Applied Chemistry 83, no. 3 (January 16, 2011): 553–63. http://dx.doi.org/10.1351/pac-con-10-09-10.

Повний текст джерела

Анотація:

Olefin metathesis as a catalytic process constantly gains interest among organic chemists. Over the last decade, it became an efficient tool to accomplish the synthesis of many complex molecules. The development of new well-defined catalysts and continuous examination of novel ligands led to the establishment of metathesis methodology in a group of widespread chemical transformations. Not only does the selection of the catalyst seem to be of crucial importance, but modifying the reaction conditions, such as choice of the solvent and temperature, also allows one to make olefin metathesis a practical industrial process. This contribution, based on examples from our research, is devoted to answering the question “What may have a greater impact on the performance of metathesis reaction: a sophisticated catalyst design or unique reaction conditions?” Based on the data reported in the paper, we discuss two complementary strategies concerning the tuning of the olefin metathesis process.

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Liu, Wenbo, and Chao-Jun Li. "Recent Synthetic Applications of Catalyst-Free Photochemistry." Synlett 28, no. 20 (September 14, 2017): 2714–54. http://dx.doi.org/10.1055/s-0036-1590900.

Повний текст джерела

Анотація:

Catalyst-free photochemistry provides numerous opportunities toward sustainable synthesis because catalyst separation can usually be avoided, which is consistent with green chemistry principles. Complementary to the well-reviewed photoredox chemistry, this review specifically summarizes the synthetic applications of photochemistry without external catalysts reported since 2000. The selected examples include both natural product synthesis and new methodology development. This review is arranged based on the type of chromophore. It is our hope that this review will inspire more synthetic chemists to embrace photochemistry into their research plans.1 Introduction2 Photochemistry of Olefins2.1 [2+2] Cycloaddition of Enones and Olefins2.2 Cycloaddition of Olefins without Carbonyl Groups2.3 Z/E Isomerization2.4 Cyclization2.5 Others3 Photochemistry of C=O3.1 The Paternò–Büchi Reaction3.2 The Yang Photoenolization3.3 The Norrish Type I Reaction3.4 The Norrish Type II Reaction3.5 Others4 Photochemistry of Nitrogen-Containing Functional Groups5 Photochemistry of Halogen-Containing Compounds6 Conclusion and Outlook

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Huang, Xin, Zengbei Li, Zhengguo Yu, Xinjie Deng, and Yi Xin. "Recent Advances in the Synthesis, Properties, and Biological Applications of Platinum Nanoclusters." Journal of Nanomaterials 2019 (September 8, 2019): 1–31. http://dx.doi.org/10.1155/2019/6248725.

Повний текст джерела

Анотація:

Noble metal nanoclusters (M NCs), defined as an aggregation of a few to tens of atoms, are considered a borderline between atoms and metal nanoparticles (M NPs), which tends to exhibit molecule-like behaviours such as discrete electronic state and size-dependent fluorescence. In the past decades, gold and silver nanoclusters (Au NCs and Ag NCs) have been massively explored and utilized in the field of industrial catalysis, optoelectronic devices, biological imaging, environmental detection, clinical diagnoses, and treatment. The analogue of Au and Ag NCs and platinum nanoclusters (Pt NCs), especially their biological applications, is relatively and rarely discussed. This review firstly investigates the synthetic methodology of Pt NCs including template-assisted and template-free approaches and then introduces their unique optical, catalytic, and thermal properties. Particular importance here is the biological applications of Pt NCs such as the bioimaging of various cells as a preferred fluorophore in contrast to traditional fluorescent markers (e.g., organic dye, semiconductor quantum dots, and fluorescent proteins), the usage of Pt NCs-based antitumour drugs as a new class chemotherapeutics for malignant tumour therapy, and the utilization of antibacteria as an alternative of Ag-based antibacterial agent. On the whole, the development of Pt NCs has already gained delectable progress; however, the study of ultrafine Pt NCs is at the beginning stage and there are still plenty of challenges like synthesis of near-infrared (NIR) fluorescent Pt NCs, the explicit signal pathway of cell apoptosis, and attempt in diverse biological applications that need to be urgently tackled in future.

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Malkov, Andrei V., and Aleksandr E. Rubtsov. "Developing a Methodology for Catalytic Asymmetric Crotylation of Aldehydes." Synlett 32, no. 14 (January 18, 2021): 1397–405. http://dx.doi.org/10.1055/s-0040-1706659.

Повний текст джерела

Анотація:

AbstractAsymmetric crotylation has firmly earned a place among the set of valuable synthetic tools for stereoselective construction of carbon skeletons. For a long time the field was heavily dominated by reagents bearing stoichiometric chiral auxiliaries, but now catalytic methods are gradually taking center stage, and the area continues to develop rapidly. This account focuses primarily on preformed organometallic reagents based on silicon and, to some extent, boron. It narrates our endeavors to design new and efficient chiral Lewis base catalysts for the asymmetric addition of crotyl(trichloro)silanes to aldehydes. It also covers the development of a novel protocol for kinetic resolution of racemic secondary allylboronates to give enantio- and diastereomerically enriched linear homoallylic alcohols. As a separate topic, cross-crotylation of aldehydes by using enantiopure branched homoallylic alcohols as a source of crotyl groups is discussed. Finally, the synthetic credentials of the developed methodology are illustrated by total syntheses of marine natural products, in which crotylation plays a key role in setting up stereogenic centers.1 Introduction2 Pyridine N-Oxides as Lewis Base Catalysts3 Bipyridine N,N′-Dioxides as Lewis Base Catalysts4 Chiral Allylating Reagents5 Synthetic Applications6 Concluding Remarks

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Hall, Dennis G. "New preparative methods for allylic boronates and their application in stereoselective catalytic allylborations." Pure and Applied Chemistry 80, no. 5 (January 1, 2008): 913–27. http://dx.doi.org/10.1351/pac200880050913.

Повний текст джерела

Анотація:

Stereocontrolled additions of allylic metal reagents to carbonyl compounds constitute one of the most useful classes of transformations in organic synthesis. The recent development of Lewis and Brønsted acid-catalyzed manifolds for the allylboration of carbonyl compounds has opened doors toward an ideal carbonyl allylation methodology using stable and nontoxic allylic boronates as reagents. This paper describes the development of acid-catalyzed allylborations, mechanistic investigations of these new processes, and ongoing efforts toward general catalytic enantioselective allylboration methodologies. The preparation of optically enriched α-substituted allylic boronate reagents is discussed, as well as their applications in Lewis acid-catalyzed additions to afford skeletally diverse products like propionate units, polysubstituted furans, vinylcyclopropanes, and larger ring systems.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Myers, Deborah J., Ahmed A. Farghaly, Magali Ferrandon, A. Jeremy Kropf, and David A. Cullen. "Platinum Group Metal-Free Oxygen Evolution Electrocatalysts for Alkaline Water Electrolysis." ECS Meeting Abstracts MA2022-02, no. 44 (October 9, 2022): 1672. http://dx.doi.org/10.1149/ma2022-02441672mtgabs.

Повний текст джерела

Анотація:

The sluggish kinetics of oxygen electrocatalysis and the resulting high overpotentials necessary to achieve useful current densities limit the development of promising technologies, such as fuel cells, water, and carbon dioxide electrolyzers, and metal-oxygen batteries.1 The best catalysts for both the oxygen reduction and oxygen evolution reactions (ORR and OER, respectively) are based on precious, platinum group metals (PGMs), such as platinum and iridium, leading to limitations in the cost-effective implementation of these technologies.2,3 The development of alternative catalysts, with comparable or higher activity and durability to the PGM catalysts and derived from earth-abundant materials has thus been an active research area for decades. Incredible progress has been made in developing PGM-free electrocatalysts for the OER in alkaline environments, with perovskite oxides showing activities comparable to PGM-based catalysts.4,5 Perovskite oxides are a very broad class of materials with the general formula of ABO3, where the B site is occupied by smaller transition metal ions and the A site by larger cations which have 12-fold coordination with O.4 Both the A sites and B sites can be occupied by multiple metal ions, leading to an even more expansive design space for this class of materials. Another interesting class of catalysts is Fe and Ni oxides derived from the electrochemical oxidation of metal-organic frameworks (MOFs), with the advantages of this material over the perovskites being high electronic conductivity and high surface area. This presentation will describe the development and application of a high-throughput methodology to accelerate the exploration of the effects of composition and synthesis parameters on the activity of perovskite oxide and metal-organic framework-derived alkaline electrolyte OER catalysts. The evolution of the oxidation state and atomic structure of the MOF materials in the electrochemical environment, as determined using in situ X-ray absorption spectroscopy (XAS), as well as the evolution of the morphology of the catalyst, as determined using electron microscopy, will be described. References Yang, X. Han, A.I. Douka, L. Huang, L. Gong, C. Xia, H.S. Park, and B.Y. Xia, Adv. Func. Mater., 31 (2021) 2007602. Pivovar, Nature Catalysis, 2 (2019) 562. Thompson and D. Papageorgopoulos, Nature Catalysis, 2 (2019) 558. Hwang, R.R. Rao, L. Giordano, Y. Katayama, Y. Yu, and Y. Shao-Horn, Science 358 (2017) 751. Suntivich, K.J. May, H.A. Gasteiger, J.B. Goodenough, Y. Shao-Horn, Science, 334 (2011) 1383. Acknowledgements This work was supported by the U.S. Department of Energy (DOE), Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (HFTO) under the auspices of the Electrocatalysis Consortium (ElectroCat 2.0). This work was also supported by DOE, Advanced Research Projects Agency-Energy (ARPA-E) under the DIFFERENTIATE program. This work utilized the resources of the Advanced Photon Source, a DOE Office of Science user facility operated by Argonne National Laboratory for DOE Office and was authored by Argonne, a DOE Office of Science laboratory operated for DOE by UChicago Argonne, LLC under contract no. DE-AC02-06CH11357.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Roy, Snigdha. "Prins-Friedel-Crafts Cyclization: Synthesis of Diversely Functionalized Six- Membered Oxacycles." Current Organic Chemistry 25, no. 5 (March 15, 2021): 635–51. http://dx.doi.org/10.2174/1385272825666210114105020.

Повний текст джерела

Анотація:

Prins cyclization is a well-established synthetic protocol to generate a wide range of important oxygen heterocycles. It is a cyclization reaction performed by an oxocarbenium ion that undergoes an intramolecular pi-bond attack to construct a new carbon-carbon bond. When this cyclization process is conjugated with Friedel-Crafts reaction, it further expands the synthetic potential by fabricating two different carbon-carbon bonds in one single reaction. Different acid catalysts mediated the coupled Prins-Friedel-Crafts reaction which is conducted both in stepwise as well as in tandem fashion. In the stepwise route, three different reacting components were utilized whereas, the tandem methodology required proper modification of the initial substrate molecule. An array of allylic, propargylic, other related alkenols, and carbonyl reactants were employed to carry out the cyclization process. Several oxygenated heterocycles equipped with diverse functionalities were constructed in a stereoselective manner which again reinforced the significance of this cyclization protocol undoubtedly. The present mini-review highlights the utilization of different one-pot stepwise Prins-Friedel-Crafts reactions and the subsequent development of cascade Prins- Friedel-Crafts cyclization process to furnish intricate molecular architectures of vital six-membered oxacycles.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Hiyama, Tamejiro. "Preface." Pure and Applied Chemistry 77, no. 7 (January 1, 2005): iv. http://dx.doi.org/10.1351/pac20057707iv.

Повний текст джерела

Анотація:

Organic synthesis has long played a pivotal role in the chemical sciences. It is therefore unsurprising and appropriate that the International Conferences on Organic Synthesis (ICOS) continue to thrive. This series was initiated by IUPAC in 1976 and has since featured biennially as one of the core events of the Union. What is surprising is that 22 years have elapsed since an ICOS event was last hosted by Japan. On that occasion, ICOS-4 was held in 1982 at Shinjuku, Tokyo, and was acclaimed as a great success. The latest event (ICOS-15), in Nagoya, Japan on 1ñ6 August 2004, offered an opportunity to match or surpass the impact of its predecessoróa challenge that was taken up enthusiastically under the leadership of Profs. Minoru Isobe (Nagoya University) and Hisashi Yamamoto (now at the University of Chicago) as Conference co-Chairs. Almost 1000 participants converged on Nagoya from all parts of the world. A noticeably high level of participation by delegates from East Asia in relation to those from North America and Europe attested to the growing capacity of this region to contribute to research at the forefront of this area of the chemical sciences. The scientific program of the Conference embraced all aspects of modern synthetic organic chemistry, inter alia, the invention of selective synthetic methods, asymmetric synthesis, total synthesis of natural products, design and synthesis of artificial agents for pharmaceutical and agricultural uses, and molecular assembly and materials based on molecular function. This topical breadth was also captured in a poster program, which was handsomely supported by no less than 466 displays on every conceivable facet of the subject. Overall, it is evident that organic synthesis has expanded its boundaries increasingly toward biological and material sciences, in response to the new challenges arising from rapid progress in molecular biology and applied physics during recent years.A lecture program comprising 10 plenary and 20 invited presentations, in addition to the Thieme/IUPAC award lecture and two Nagoya medal lectures, contributed to a truly exciting Conference experience, and the 21 speakers who kindly agreed to contribute papers based upon their presentations have made it possible to capture some of the excitement in this issue of Pure and Applied Chemistry. The Nagoya Gold Medallist, J. F. Stoddart, used the occasion to share an absorbing and very personal perspective on molecular assembly and materials, a theme on which M. Fujita also disclosed new insights and developments. The perennial theme of total synthesis of natural products, provided scope for presentation of highly creative accomplishments by S. Ley, J. Cossy, Y. Langlois, R. Pilli, and S. Kozmin on a variety of challenging targets. Such advances in the total synthesis of biologically active natural products having extremely complex structures, often necessitate development of novel synthetic methods, and H. Overkleeft, P. Chiu, V. Nair, T.-P. Loh, S. Martin, T.-Y. Luh, E. Juaristi, and M. Catellani did justice to this theme with presentations on a variety of extremely elegant and sophisticated new developments in methodology, based upon organometallic catalysts and/or reagents. Finally, the broad theme of asymmetric synthesis using organometallic complexes with chiral ligands or chiral organocatalysts was developed in conjunction with combinatorial methodology, which is shown to be highly effective in optimizing catalytic systems. Those who contributed to the topic of asymmetric synthesis are K. Ding, A. Charette, S. H. Kang, A. Berkessel, and K. Maruoka, the recipient of the Nagoya Silver Medal.What is the future of organic synthesis? The invention of unprecedented drugs and materials has enriched and expanded the horizons of the human experience in formerly unimagined ways, and owes much to the ever increasing ingenuity of organic synthesis, and recognition and attainment of new synthetic targets. The impact of organic synthesis on cognate disciplines and on general advancement of science and technology is definitely enormous and will be further strengthened by future challenges and opportunities. Thus, it is hoped that younger generations will be inspired to participate in tapping this rich potential, in the cause of advancing science and contributing to the enrichment of future life. These aspirations may yield incalculable rewards. Such progress will certainly be reflected in the scientific program of the next Conference in the ICOS series, which will take place in Merida, Yucatan, Mexico on 11ñ15 June 2006, under the chairmanship of Dr. Eusebio Juaristi, Instituto Politecnico Nacional, Mexico.Tamejiro HiyamaConference EditorDepartment of Material ChemistryKyoto University, Kyoto, Japan *An issue of reviews and research papers based on lectures presented at the 15th International Conference on Organic Synthesis (ICOS-15), held in Nagoya, Japan, 1-6 August 2004, on the theme of organic synthesis. Other presentations are published in this issue, pp. 1087-1296.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Kocaarslan, Azra, Zafer Eroglu, Önder Metin, and Yusuf Yagci. "Exfoliated black phosphorous-mediated CuAAC chemistry for organic and macromolecular synthesis under white LED and near-IR irradiation." Beilstein Journal of Organic Chemistry 17 (September 23, 2021): 2477–87. http://dx.doi.org/10.3762/bjoc.17.164.

Повний текст джерела

Анотація:

The development of long-wavelength photoinduced copper-catalyzed azide–alkyne click (CuAAC) reaction routes is attractive for organic and polymer chemistry. In this study, we present a novel synthetic methodology for the photoinduced CuAAC reaction utilizing exfoliated two-dimensional (2D) few-layer black phosphorus nanosheets (BPNs) as photocatalysts under white LED and near-IR (NIR) light irradiation. Upon irradiation, BPNs generated excited electrons and holes on its conduction (CB) and valence band (VB), respectively. The excited electrons thus formed were then transferred to the CuII ions to produce active CuI catalysts. The ability of BPNs to initiate the CuAAC reaction was investigated by studying the reaction between various low molar mass alkyne and azide derivatives under both white LED and NIR light irradiation. Due to its deeper penetration of NIR light, the possibility of synthesizing different macromolecular structures such as functional polymers, cross-linked networks and block copolymer has also been demonstrated. The structural and molecular properties of the intermediates and final products were evaluated by spectral and chromatographic analyses.

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Moore, Eric J., Dmitri Zorine, William A. Hansen, Sagar D. Khare, and Rudi Fasan. "Enzyme stabilization via computationally guided protein stapling." Proceedings of the National Academy of Sciences 114, no. 47 (November 6, 2017): 12472–77. http://dx.doi.org/10.1073/pnas.1708907114.

Повний текст джерела

Анотація:

Thermostabilization represents a critical and often obligatory step toward enhancing the robustness of enzymes for organic synthesis and other applications. While directed evolution methods have provided valuable tools for this purpose, these protocols are laborious and time-consuming and typically require the accumulation of several mutations, potentially at the expense of catalytic function. Here, we report a minimally invasive strategy for enzyme stabilization that relies on the installation of genetically encoded, nonreducible covalent staples in a target protein scaffold using computational design. This methodology enables the rapid development of myoglobin-based cyclopropanation biocatalysts featuring dramatically enhanced thermostability (ΔTm = +18.0 °C and ΔT50 = +16.0 °C) as well as increased stability against chemical denaturation [ΔCm (GndHCl) = 0.53 M], without altering their catalytic efficiency and stereoselectivity properties. In addition, the stabilized variants offer superior performance and selectivity compared with the parent enzyme in the presence of a high concentration of organic cosolvents, enabling the more efficient cyclopropanation of a water-insoluble substrate. This work introduces and validates an approach for protein stabilization which should be applicable to a variety of other proteins and enzymes.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Mitsudo, Koichi, Yuji Kurimoto, Jun Yamashita, and Seiji Suga. "(Digital Presentation) Electrochemical Dehydrogenative C–P Bond Formation for the Synthesis of Phosphacycles Using DABCO As a Mediator." ECS Meeting Abstracts MA2022-01, no. 42 (July 7, 2022): 1838. http://dx.doi.org/10.1149/ma2022-01421838mtgabs.

Повний текст джерела

Анотація:

Phosphole oxide-containing π-conjugated molecules have been attracting attention due to their electron acceptability and thermal and chemical stability, and have been used as an important motif for organic functional materials. Among them, diarylphosphole oxide (DPO) is a key motif in the design of phosphole-containing organic functional materials. Recently, intramolecular cyclization of biarylphosphine oxides (BPOs) has received attention as a straightforward way leading to DPOs. BPOs are readily available and easy to handle starting substrates. Although several efficient methods have been reported for synthesizing DPOs with this protocol, these methods require transition metal catalysts, strong acids or excess amounts of acid. Therefore, the development of a transition metal-free and environmentally benign synthetic methodology for synthesizing DPOs is highly desirable. To overcome the situation, we developed the first electrochemical synthesis of DPOs from BPOs via a dehydrogenative C–P bond formation. The protocol does not use a transition metal mediator and instead uses readily available and inexpensive DABCO as an organic hydrogen atom transfer (HAT) mediator. In the presence of DABCO, the desired C–P bond formation proceeded smoothly and a wide variety of DPOs could be obtained. This method can also be applied to the synthesis of six-membered phosphacycles. Several control experiments were carried out, and the results suggest that a phosphinyl radical was generated in situ and the reaction would proceed via a radical pathway. Figure 1

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Woźny, Mateusz, Adam Mames, and Tomasz Ratajczyk. "Triptycene Derivatives: From Their Synthesis to Their Unique Properties." Molecules 27, no. 1 (December 31, 2021): 250. http://dx.doi.org/10.3390/molecules27010250.

Повний текст джерела

Анотація:

Since the first preparation of triptycene, great progress has been made with respect to its synthesis and the understanding of its properties. Interest in triptycene-based systems is intense; in recent years, advances in the synthetic methodology and properties of new triptycenes have been reported by researchers from various fields of science. Here, an account of these new developments is given and placed in reference to earlier pivotal works that underpin the field. First, we discuss new approaches to the synthesis of new triptycenes. Progress in the regioselective synthesis of sterically demanding systems is discussed. The application of triptycenes in catalysis is also presented. Next, progress in the understanding of the relations between triptycene structures and their properties is discussed. The unique properties of triptycenes in the liquid and solid states are elaborated. Unique interactions, which involve triptycene molecular scaffolds, are presented. Molecular interactions within a triptycene unit, as well as between triptycenes or triptycenes and other molecules, are also evaluated. In particular, the summary of the synthesis and useful features will be helpful to researchers who are using triptycenes as building blocks in the chemical and materials sciences.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Qasim, Muhammad, Andrew N. Clarkson, and Simon F. R. Hinkley. "Green Synthesis of Carbon Nanoparticles (CNPs) from Biomass for Biomedical Applications." International Journal of Molecular Sciences 24, no. 2 (January 5, 2023): 1023. http://dx.doi.org/10.3390/ijms24021023.

Повний текст джерела

Анотація:

In this review, we summarize recent work on the “green synthesis” of carbon nanoparticles (CNPs) and their application with a focus on biomedical applications. Recent developments in the green synthesis of carbon nanoparticles, from renewable precursors and their application for environmental, energy-storage and medicinal applications are discussed. CNPs, especially carbon nanotubes (CNTs), carbon quantum dots (CQDs) and graphene, have demonstrated utility as high-density energy storage media, environmental remediation materials and in biomedical applications. Conventional fabrication of CNPs can entail the use of toxic catalysts; therefore, we discuss low-toxicity manufacturing as well as sustainable and environmentally friendly methodology with a focus on utilizing readily available biomass as the precursor for generating CNPs.

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Luque-Jacobo, Cristina M., Andrea L. Cespedes-Loayza, Talia S. Echegaray-Ugarte, Jacqueline L. Cruz-Loayza, Isemar Cruz, Júlio Cesar de Carvalho, and Luis Daniel Goyzueta-Mamani. "Biogenic Synthesis of Copper Nanoparticles: A Systematic Review of Their Features and Main Applications." Molecules 28, no. 12 (June 18, 2023): 4838. http://dx.doi.org/10.3390/molecules28124838.

Повний текст джерела

Анотація:

Nanotechnology is an innovative field of study that has made significant progress due to its potential versatility and wide range of applications, precisely because of the development of metal nanoparticles such as copper. Nanoparticles are bodies composed of a nanometric cluster of atoms (1–100 nm). Biogenic alternatives have replaced their chemical synthesis due to their environmental friendliness, dependability, sustainability, and low energy demand. This ecofriendly option has medical, pharmaceutical, food, and agricultural applications. When compared to their chemical counterparts, using biological agents, such as micro-organisms and plant extracts, as reducing and stabilizing agents has shown viability and acceptance. Therefore, it is a feasible alternative for rapid synthesis and scaling-up processes. Several research articles on the biogenic synthesis of copper nanoparticles have been published over the past decade. Still, none provided an organized, comprehensive overview of their properties and potential applications. Thus, this systematic review aims to assess research articles published over the past decade regarding the antioxidant, antitumor, antimicrobial, dye removal, and catalytic activities of biogenically synthesized copper nanoparticles using the scientific methodology of big data analytics. Plant extract and micro-organisms (bacteria and fungi) are addressed as biological agents. We intend to assist the scientific community in comprehending and locating helpful information for future research or application development.

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Kristensen, Tor E. "Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications." Beilstein Journal of Organic Chemistry 11 (April 8, 2015): 446–68. http://dx.doi.org/10.3762/bjoc.11.51.

Повний текст джерела

Анотація:

Amino acids, whether natural, semisynthetic or synthetic, are among the most important and useful chiral building blocks available for organic chemical synthesis. In principle, they can function as inexpensive, chiral and densely functionalized starting materials. On the other hand, the use of amino acid starting materials routinely necessitates protective group chemistry, and in reality, large-scale preparations of even the simplest side-chain derivatives of many amino acids often become annoyingly strenuous due to the necessity of employing protecting groups, on one or more of the amino acid functionalities, during the synthetic sequence. However, in the case of hydroxyamino acids such as hydroxyproline, serine, threonine, tyrosine and 3,4-dihydroxyphenylalanine (DOPA), many O-acyl side-chain derivatives are directly accessible via a particularly expedient and scalable method not commonly applied until recently. Direct acylation of unprotected hydroxyamino acids with acyl halides or carboxylic anhydrides under appropriately acidic reaction conditions renders possible chemoselective O-acylation, furnishing the corresponding side-chain esters directly, on multigram-scale, in a single step, and without chromatographic purification. Assuming a certain degree of stability under acidic reaction conditions, the method is also applicable for a number of related compounds, such as various amino alcohols and the thiol-functional amino acid cysteine. While the basic methodology underlying this approach has been known for decades, it has evolved through recent developments connected to amino acid-derived chiral organocatalysts to become a more widely recognized procedure for large-scale preparation of many useful side-chain derivatives of hydroxyamino acids and related compounds. Such derivatives are useful in peptide chemistry and drug development, as amino acid amphiphiles for asymmetric catalysis, and as amino acid acrylic precursors for preparation of catalytically active macromolecular networks in the form of soluble polymers, crosslinked polymer beads or nanoparticulate systems. The objective of the present review is to increase awareness of the existence and convenience of this methodology, assess its competitiveness compared to newer and more elaborate procedures for chemoselective O-acylation reactions, spur its further development, and finally to chronicle the informative, but poorly documented history of its development.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Cai, Jiayou, Bin Sun, Siqi Yu, Han Zhang, and Weicheng Zhang. "Heck Macrocyclization in Forging Non-Natural Large Rings including Macrocyclic Drugs." International Journal of Molecular Sciences 24, no. 9 (May 4, 2023): 8252. http://dx.doi.org/10.3390/ijms24098252.

Повний текст джерела

Анотація:

The intramolecular Heck reaction is a well-established strategy for natural product total synthesis. When constructing large rings, this reaction is also referred to as Heck macrocyclization, which has proved a viable avenue to access diverse naturally occurring macrocycles. Less noticed but likewise valuable, it has created novel macrocycles of non-natural origin that neither serve as nor derive from natural products. This review presents a systematic account of the title reaction in forging this non-natural subset of large rings, thereby addressing a topic rarely covered in the literature. Walking through two complementary sections, namely (1) drug discovery research and (2) synthetic methodology development, it demonstrates that beyond the well-known domain of natural product synthesis, Heck macrocyclization also plays a remarkable role in forming synthetic macrocycles, in particular macrocyclic drugs.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Noor, Rida, Ameer Fawad Zahoor, Muhammad Irfan, Syed Makhdoom Hussain, Sajjad Ahmad, Ali Irfan, Katarzyna Kotwica-Mojzych, and Mariusz Mojzych. "Transition Metal Catalyzed Hiyama Cross-Coupling: Recent Methodology Developments and Synthetic Applications." Molecules 27, no. 17 (September 2, 2022): 5654. http://dx.doi.org/10.3390/molecules27175654.

Повний текст джерела

Анотація:

Hiyama cross-coupling is a versatile reaction in synthetic organic chemistry for the construction of carbon–carbon bonds. It involves the coupling of organosilicons with organic halides using transition metal catalysts in good yields and high enantioselectivities. In recent years, hectic progress has been made by researchers toward the synthesis of diversified natural products and pharmaceutical drugs using the Hiyama coupling reaction. This review emphasizes the recent synthetic developments and applications of Hiyama cross-coupling.

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Akácsos-Szász, Orsolya-Zsuzsa, Sándor Pál, Kinga-Ilona Nyulas, Enikő Nemes-Nagy, Ana-Maria Fárr, Lóránd Dénes, Mónika Szilveszter, Erika-Gyöngyi Bán, Mariana Cornelia Tilinca, and Zsuzsánna Simon-Szabó. "Pathways of Coagulopathy and Inflammatory Response in SARS-CoV-2 Infection among Type 2 Diabetic Patients." International Journal of Molecular Sciences 24, no. 5 (February 21, 2023): 4319. http://dx.doi.org/10.3390/ijms24054319.

Повний текст джерела

Анотація:

Chronic inflammation and endothelium dysfunction are present in diabetic patients. COVID-19 has a high mortality rate in association with diabetes, partially due to the development of thromboembolic events in the context of coronavirus infection. The purpose of this review is to present the most important underlying pathomechanisms in the development of COVID-19-related coagulopathy in diabetic patients. The methodology consisted of data collection and synthesis from the recent scientific literature by accessing different databases (Cochrane, PubMed, Embase). The main results are the comprehensive and detailed presentation of the very complex interrelations between different factors and pathways involved in the development of arteriopathy and thrombosis in COVID-19-infected diabetic patients. Several genetic and metabolic factors influence the course of COVID-19 within the background of diabetes mellitus. Extensive knowledge of the underlying pathomechanisms of SARS-CoV-2-related vasculopathy and coagulopathy in diabetic subjects contributes to a better understanding of the manifestations in this highly vulnerable group of patients; thus, they can benefit from a modern, more efficient approach regarding diagnostic and therapeutic management.

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Smolskaya, Sviatlana, Yulia A. Logashina, and Yaroslav A. Andreev. "Escherichia coli Extract-Based Cell-Free Expression System as an Alternative for Difficult-to-Obtain Protein Biosynthesis." International Journal of Molecular Sciences 21, no. 3 (January 31, 2020): 928. http://dx.doi.org/10.3390/ijms21030928.

Повний текст джерела

Анотація:

Before utilization in biomedical diagnosis, therapeutic treatment, and biotechnology, the diverse variety of peptides and proteins must be preliminarily purified and thoroughly characterized. The recombinant DNA technology and heterologous protein expression have helped simplify the isolation of targeted polypeptides at high purity and their structure-function examinations. Recombinant protein expression in Escherichia coli, the most-established heterologous host organism, has been widely used to produce proteins of commercial and fundamental research interests. Nonetheless, many peptides/proteins are still difficult to express due to their ability to slow down cell growth or disrupt cellular metabolism. Besides, special modifications are often required for proper folding and activity of targeted proteins. The cell-free (CF) or in vitro recombinant protein synthesis system enables the production of such difficult-to-obtain molecules since it is possible to adjust reaction medium and there is no need to support cellular metabolism and viability. Here, we describe E. coli-based CF systems, the optimization steps done toward the development of highly productive and cost-effective CF methodology, and the modification of an in vitro approach required for difficult-to-obtain protein production.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Kus-Liśkiewicz, Małgorzata, Patrick Fickers, and Imen Ben Tahar. "Biocompatibility and Cytotoxicity of Gold Nanoparticles: Recent Advances in Methodologies and Regulations." International Journal of Molecular Sciences 22, no. 20 (October 11, 2021): 10952. http://dx.doi.org/10.3390/ijms222010952.

Повний текст джерела

Анотація:

Recent advances in the synthesis of metal nanoparticles (MeNPs), and more specifically gold nanoparticles (AuNPs), have led to tremendous expansion of their potential applications in different fields, ranging from healthcare research to microelectronics and food packaging. The properties of functionalised MeNPs can be fine-tuned depending on their final application, and subsequently, these properties can strongly modulate their biological effects. In this review, we will firstly focus on the impact of MeNP characteristics (particularly of gold nanoparticles, AuNPs) such as shape, size, and aggregation on their biological activities. Moreover, we will detail different in vitro and in vivo assays to be performed when cytotoxicity and biocompatibility must be assessed. Due to the complex nature of nanomaterials, conflicting studies have led to different views on their safety, and it is clear that the definition of a standard biosafety label for AuNPs is difficult. In fact, AuNPs’ biocompatibility is strongly affected by the nanoparticles’ intrinsic characteristics, biological target, and methodology employed to evaluate their toxicity. In the last part of this review, the current legislation and requirements established by regulatory authorities, defining the main guidelines and standards to characterise new nanomaterials, will also be discussed, as this aspect has not been reviewed recently. It is clear that the lack of well-established safety regulations based on reliable, robust, and universal methodologies has hampered the development of MeNP applications in the healthcare field. Henceforth, the international community must make an effort to adopt specific and standard protocols for characterisation of these products.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Dangi, Hemlata, Atish Roy, Aayushi Chanderiya, Sushil Kashaw, and Ratnesh Das. "One pot synthesis of some novel indole derivatives and their antimicrobial activity." Mediterranean Journal of Chemistry 13, no. 1 (February 3, 2023): 42. http://dx.doi.org/10.13171/mjc02302031664das-dangi.

Повний текст джерела

Анотація:

<p>In this study, we describe the creation of a straightforward and incredibly effective protocol for the synthesis of new 3-Substituted indole derivatives. This multicomponent reaction involved indole, acetylacetone and active aldehyde derivatives in the presence of ethanol as solvent followed by acetonitrile as a base. We go through current developments in organic synthesis methodology for multicomponent reactions that produce substituted indole derivatives with a more environmentally friendly base catalytic condition, as well as the applications that go along with them. FT-IR, 1H-NMR and MS are used to characterise the synthesized compound of indole derivatives. Antibacterial activity of synthesized compounds has also been done. </p>

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Gabriele, Bartolo. "Organic Synthesis via Transition Metal-Catalysis." Molecules 27, no. 4 (February 11, 2022): 1227. http://dx.doi.org/10.3390/molecules27041227.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Makosza, Mieczyslaw. "Phase-transfer catalysis. A general green methodology in organic synthesis." Pure and Applied Chemistry 72, no. 7 (January 1, 2000): 1399–403. http://dx.doi.org/10.1351/pac200072071399.

Повний текст джерела

Анотація:

Basic concept of phase-transfer catalysis (PTC), its field of applications and specific features as the most general, efficient, and environment-friendly green methodology of organic synthesis, particularly for industrial processes, is discussed.

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Dou, Qian, Taimin Wang, Lijing Fang, Hongbin Zhai, and Bin Cheng. "Recent Development of Photoinduced Iron-Catalysis in Organic Synthesis." Chinese Journal of Organic Chemistry 43, no. 4 (2023): 1386. http://dx.doi.org/10.6023/cjoc202209001.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Kobayashi, Shū, and Kei Manabe. "Green Lewis acid catalysis in organic synthesis." Pure and Applied Chemistry 72, no. 7 (January 1, 2000): 1373–80. http://dx.doi.org/10.1351/pac200072071373.

Повний текст джерела

Анотація:

New types of Lewis acids as water-stable catalysts have been developed. Metal salts such as rare earth metal triflates can be used in carbon_carbon bond-forming reactions in aqueous media. These salts can be recovered after the reactions and reused. Furthermore, Lewis acid_surfactant-combined catalysts, which can be used for reactions in water without using any organic solvents, have been also developed. Finally, Lewis acid catalysis in supercritical carbon dioxide has been successfully performed. These investigations will contribute to development of environmentally friendly Lewis acid catalysis.

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Li, Hong-Xi, Da-Liang Zhu, and David James Young. "Carbonyl-Photoredox/Metal Dual Catalysis: Applications in Organic Synthesis." Synthesis 52, no. 23 (July 21, 2020): 3493–510. http://dx.doi.org/10.1055/s-0040-1707183.

Повний текст джерела

Анотація:

Photoredox/metal dual catalysis is a versatile tandem methodology to construct carbon–carbon and carbon–heteroatom bonds. The focus of this short review is the application of this technology to C(sp3)–C(sp3), C(sp3)–C(sp2), C(sp2)–C(sp2), C(sp2)–O, and C(sp3)–O bond formation induced by readily available and inexpensive carbonyl complexes as single electron transfer agents, photosensitizers, or hydrogen atom transfer agents.1 Introduction2 Homocoupling of Aryl Halides3 Functionalization of C(sp3)–H Bonds3.1 Dehydrogenation of Alkanes3.2 Arylation/Alkylation3.3 Carboxylation3.4 Acylation3.5 Hydroalkylation of Olefins3.6 Hydroalkylation of Imines4 Benzoylation of Aryl Bromides5 Aryl Esterification6 Oxidation of β-Keto Esters7 Conclusions and Future Outlook

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Makosza, Mieczyslaw. "ChemInform Abstract: Phase-Transfer Catalysis: A General Green Methodology in Organic Synthesis." ChemInform 32, no. 16 (April 17, 2001): no. http://dx.doi.org/10.1002/chin.200116277.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

45

DaBell, Peter, and Stephen P. Thomas. "Iron Catalysis in Target Synthesis." Synthesis 52, no. 07 (February 5, 2020): 949–63. http://dx.doi.org/10.1055/s-0039-1690813.

Повний текст джерела

Анотація:

The use of iron-catalysed organic transformations in the total syntheses of natural products has increased significantly. Iron-catalysed cross-coupling reactions are now widely applied in total syntheses and many other transformations, such as alkene functionalisation, oxidation, and cyclisation. The development of these processes, as well as many examples of their use in target synthesis, is presented here.1 Introduction2 Cross-Coupling Reactions3 Functionalisation of Unactivated Alkenes4 Carbocyclisation Reactions5 Oxidations6 Further Examples7 Conclusions

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Beatty, Joel W., and Corey R. J. Stephenson. "Amine Functionalization via Oxidative Photoredox Catalysis: Methodology Development and Complex Molecule Synthesis." Accounts of Chemical Research 48, no. 5 (May 7, 2015): 1474–84. http://dx.doi.org/10.1021/acs.accounts.5b00068.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

47

ISAYAMA, Shigeru. "Development of Novel Methodology in Organic Synthesis Using Cobalt(II) Catalyst." Journal of Synthetic Organic Chemistry, Japan 50, no. 3 (1992): 190–201. http://dx.doi.org/10.5059/yukigoseikyokaishi.50.190.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Tian, Wei, and Spiros Grivas. "A Useful Methodology for the Synthesis of 2-Methyl-4-nitrobenzimidazoles." Synthesis 1992, no. 12 (1992): 1283–86. http://dx.doi.org/10.1055/s-1992-26359.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Beeler, Aaron, John Porco Jr., John Goodell, Bo Leng, and Tracy Snyder. "Multidimensional Screening and Methodology Development for Condensations Involving Complex 1,2-Diketones." Synthesis 2010, no. 13 (June 11, 2010): 2254–70. http://dx.doi.org/10.1055/s-0029-1218813.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Filipczak, Nina, Satya Siva Kishan Yalamarty, Xiang Li, Farzana Parveen, and Vladimir Torchilin. "Developments in Treatment Methodologies Using Dendrimers for Infectious Diseases." Molecules 26, no. 11 (May 31, 2021): 3304. http://dx.doi.org/10.3390/molecules26113304.

Повний текст джерела

Анотація:

Dendrimers comprise a specific group of macromolecules, which combine structural properties of both single molecules and long expanded polymers. The three-dimensional form of dendrimers and the extensive possibilities for use of additional substrates for their construction creates a multivalent potential and a wide possibility for medical, diagnostic and environmental purposes. Depending on their composition and structure, dendrimers have been of interest in many fields of science, ranging from chemistry, biotechnology to biochemical applications. These compounds have found wide application from the production of catalysts for their use as antibacterial, antifungal and antiviral agents. Of particular interest are peptide dendrimers as a medium for transport of therapeutic substances: synthetic vaccines against parasites, bacteria and viruses, contrast agents used in MRI, antibodies and genetic material. This review focuses on the description of the current classes of dendrimers, the methodology for their synthesis and briefly drawbacks of their properties and their use as potential therapies against infectious diseases.

Стилі APA, Harvard, Vancouver, ISO та ін.

Статті в журналах з теми "Organic synthesis, Catalysis, and methodology development"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями