Field Of Organic Chemistry Research Articles

Recent Progress in Haloalkene Synthesis by Hydrohalogenation (HX=HCl, HBr, HI) of Alkynes

AbstractHydrohalogenation of alkynes is one of the fundamental reactions in organic chemistry, as described in textbooks that begins from old time as Reppe's chemistry. This method, which directly affords haloalkenes in a single step, is attractive from both industrial and academic viewpoints. Despite the long history of this reaction, novel efficient catalysts and regioselective and/or stereoselective controlled reactions are still a challenging topic. This review addresses the recent (past decade) advances in this field of organic chemistry.

Живот, посветен на науката. 100 години от рождението на проф. д.х.н. Елена Киркова

In this article we'll present the life path, the teaching and scientific work of the outstanding Bulgarian scientist in the field of inorganic chemistry Prof. Dr. Elena Kirkova. A brief review of her now classic textbooks on general and inorganic chemistry, her main achievements in the field of crystallization and co-crystallization processes, her contribution to linking education with scientific research and their application in practice is made.

Application of α-bromination reaction on acetophenone derivatives in experimental teaching: a chemical innovation experiment engaging junior undergraduates

The α-bromination reaction of carbonyl compounds is a significant topic in the field of organic chemistry. However, due to the lack of suitable brominating reagents, the application of this reaction in undergraduate organic chemistry experiments is limited. In this study, three junior undergraduates successfully conducted an innovative experiment under the guidance of teachers. The bromination of various acetophenone derivatives was investigated by employing pyridine hydrobromide perbromide as the brominating agent, with a focus on exploring the effects of reaction time, reaction temperature, and dosage of the brominating agent. The results demonstrated that 4-chloro-α-bromo-acetophenone could be synthesized at 90 ℃ using 4-chloroacetophenone as a substrate and acetic acid as a solvent with a molar ratio of substrate to brominator being 1.0:1.1. Through the experimental teaching of 18 junior undergraduates, it was observed that all the students successfully completed the experiment within a time frame of 4–5 h, with a notable achievement yield exceeding 80% observed in 14 students. This innovative experiment exhibits significant advantages in terms of safety, high yield, cost-effectiveness, and repeatability. Furthermore, while reinforcing fundamental skills in chemistry experimentation among students, it enhances their scientific literacy levels and fosters innovation consciousness as well as practical aptitude. Consequently, this approach is highly suitable for widespread implementation and integration into undergraduate experimental pedagogy.

Reversible Radical Addition Guides Selective Photocatalytic Intermolecular Thiol-Yne-Ene Molecular Assembly.

In modern organic chemistry, harnessing the power of multicomponent radical reactions presents both significant challenges and extraordinary potential. This article delves into this scientific frontier by addressing the critical issue of controlling selectivity in such complex processes. We introduce a novel approach that revolves around the reversible addition of thiyl radicals to multiple bonds, reshaping the landscape of multicomponent radical reactions. The key to selectivity lies in the intricate interplay between reversibility and the energy landscapes governing C-C bond formation in thiol-yne-ene reactions. The developed approach not only allows to prioritize the thiol-yne-ene cascade, dominating over alternative reactions, but also extends the scope of coupling products obtained from alkenes and alkynes of various structures and electron density distributions, regardless of their relative polarity difference, opening doors to more versatile synthetic possibilities. In the present study, we provide a powerful tool for atom-economical C-S and C-C bond formation, paving the way for the efficient synthesis of complex molecules. Carrying out our experimental and computational studies, we elucidated the fundamental mechanisms underlying radical cascades, a knowledge that can be broadly applied in the field of organic chemistry.

Reversible Radical Addition Guides Selective Photocatalytic Intermolecular Thiol‐Yne‐Ene Molecular Assembly

AbstractIn modern organic chemistry, harnessing the power of multicomponent radical reactions presents both significant challenges and extraordinary potential. This article delves into this scientific frontier by addressing the critical issue of controlling selectivity in such complex processes. We introduce a novel approach that revolves around the reversible addition of thiyl radicals to multiple bonds, reshaping the landscape of multicomponent radical reactions. The key to selectivity lies in the intricate interplay between reversibility and the energy landscapes governing C−C bond formation in thiol‐yne‐ene reactions. The developed approach not only allows to prioritize the thiol‐yne‐ene cascade, dominating over alternative reactions, but also extends the scope of coupling products obtained from alkenes and alkynes of various structures and electron density distributions, regardless of their relative polarity difference, opening doors to more versatile synthetic possibilities. In the present study, we provide a powerful tool for atom‐economical C−S and C−C bond formation, paving the way for the efficient synthesis of complex molecules. Carrying out our experimental and computational studies, we elucidated the fundamental mechanisms underlying radical cascades, a knowledge that can be broadly applied in the field of organic chemistry.

Hg3Se(SeO3)(SO4): A Mixed-Valent Selenium Compound with Mid-Infrared Transmittance Obtained by In Situ Reaction.

Exploring new material systems is a highly significant task in the field of inorganic chemistry. A new mixed-valent selenium compound, Hg3Se(SeO3)(SO4), was successfully synthesized through in situ reactions. This compound exhibits a novel three-dimensional structure composed of Hg3Se(SO4) layers bridged by SeO3 trigonal pyramids. It is the first structure containing (SeO3)2-, (SO4)2-, and Se2- simultaneously. In addition, Hg3Se(SeO3)(SO4) possesses a wide bandgap (3.5 eV), moderate birefringence (Cal:0.064@546 nm, Exp:0.069@546 nm), a high laser-induced damage threshold (23.35 MW cm-2), and a wide transmittance window (0.28-6.6 μm). Our work demonstrates that mixed-valent (+4, -2) selenite selenide can be potential optical materials for the mid-infrared region.

Kinetically Controlled Stereoselective Synthesis of 2-Oxo-2-aryl-1,3,2-dioxaphosphorinane Derivatives via a Palladium-Catalyzed Reaction.

Chiral phosphonate esters have been widely applied in the fields of organic chemistry, medicine, and photoelectric materials. However, it requires the challenging enantioselective synthesis of cyclic phosphonate esters with the desired chiral configuration. The two epimers of 2-oxo-2H-1,3,2-dioxaphosphorinane derivatives should have different reactivities in Pd-catalyzed coupling reactions, which could lead to an effective methodology for the asymmetric synthesis of 2-oxo-2-aryl-1,3,2-dioxaphosphorinane derivatives. A thorough investigation of the coupling reactions both computationally and experimentally led to the stereoselective synthesis of chiral cyclic phosphonate esters. The axial isomer of products can be obtained with both high diastereoselectivity and good chemical yields from the mixture of 2-oxo-2H-1,3,2-dioxaphosphorinane derivatives under kinetically controlled conditions.

Distortion Rules: Diene Ring Size Effects in Diels‐Alder Reactions with Triazolinediones

AbstractTriazolinediones (TADs) are highly reactive electrophiles used in several processes within the field of organic chemistry, especially in Diels‐Alder cycloadditions. The reactions of TADs with cyclic dienes have been observed to depend on the diene structure and size. To investigate the role of diene structure in the reactivity of TADs, computational chemistry based on DFT and Activation Strain Model were employed to quantitatively assess the impact of distortion and interaction energies on the observed reactivity. Calculations suggest that the reactions are endo selective based on lower energy barriers compared to the exo pathway. Additionally, the trends in reactivity agree with experimental observations: cyclopentadiene is the more reactive diene, followed by cyclohexadiene and cycloheptadiene. The ASM analysis reveals that this trend is a consequence of the degree of distortion the reactants along the reaction coordinate. These distortion energies also allowed to explain why the endo selective route is preferred over the exo one.

Selectivity in Rh-catalysis with gem-difluorinated cyclopropanes.

Small-ring chemistry is a fascinating field in organic chemistry. gem-Difluorinated cyclopropanes, a unique class of cyclopropanes, have garnered significant interest due to their intrinsic high reactivity. In this context, gem-difluorinated cyclopropanes have been extensively investigated as fluoroallylic synthons in Pd-catalyzed ring-opening/cross-coupling reactions for the synthesis of monofluoroalkenes with linear or branched selectivity. In contrast, Rh-catalysis has revealed diverse selectivity in the reaction of gem-difluorinated cyclopropanes, such as regioselectivity, enantioselectivity, and chemoselectivity. This feature article aims to summarize our efforts towards developing Rh-catalyzed reactions of gem-difluorinated cyclopropanes, briefly discussing the design, selectivity, reaction mechanisms and future research prospects.

Synthesis and Anti TB Screening of α-Acyloxy Carboxamides via Passerini MCRs Prompted by GaCl3 and PEG-400 Media

Aims: The Isocyanides based Multi-component reactions (IMCRs), and Passerini reactions were performed by using GaCl3 and PEG-400 media to generate a library of new scaffolds. Background: The Isocyanides Multi-component reactions (IMCRs) have proven their importance due to their major advantages in synthetic and medicinal areas. Among various IMCRs, Passerini stands for their pertinency in the novel adducts articulation and generates an amide functionality which shows unbeatable efficiency towards the generation of lead scaffolds. In the research fields, PEG is acting as a versatile greener solvent due to its beneficial economic advantages. In general, chiral-based separation is always a headache for the chemist and researchers tend to generate routes with major products such as single isomers. Most MCRs studied with metal-based synthesis and rather use Au or Pt-based catalyst, Gallium that has been widely explored in chiral Lewis acid catalysis, organo-catalysis, or cooperative catalysis to generate a library of compounds with high stereoselectivity with mild reaction conditions. Objective: To find diverse scaffolds in the field of organic chemistry using easily accessible metal catalysts. Methods: In this article, Enantiomerically pure, 2-(((1H-benzo[d][1,2,3]triazol-1-yl)methyl)amino)- 2-oxo-1-substitutedphenylethyl pyrazine-2-carboxylate (4a-4j), produced through a three-component passerine coupling reaction under GaCl3 as a Lewis acid-promoted conditions with diastereoseletivity ranging from moderate to good. Results: The designed approach exhibited an in situ single-step-economical path to enantiomerically pure, α-acyloxy carboxamides with pyrazine and 1H-benzo[d][1,2,3]triazole fragments employing the greener way of media through “PEG-400”. In an anti-TB screening against H37Rv, the withdrawing groups showed excellent activity compared to the donating groups. Conclusion: It was expected that the Lewis acid-PEG pairs could serve as the best catalytic transformations in eco-friendly ways and enrich the pure enantiomer of the adduct. On the medicinal side, the isolated library of compounds was screened for their biological activity against “Mycobacterium Tuberculosis H37Rv” and 4f featuring “4-F” as a substituent was found to be most active [MIC: 12.5 µg/mL].

Recent Advancement on the Indirect or Combined Alternative Thiocyanate Sources for the Construction of S-CN Bonds.

The process of thiocyanation is a notable chemical conversion owing to the extensive range of applications associated with thiocyanate compounds in the field of organic chemistry. In past centuries, the thiocyanation reaction incorporated metal thiocyanates or thiocyanate salts as sources of thiocyanate, which are environmentally detrimental and undesirable. In recent literature, there have been numerous instances where combined or indirect alternative sources of thiocyanate have been employed as agents for thiocyanation, showcasing their noteworthy applications. The present literature review focuses on elucidating the ramifications associated with the utilization of indirect or combined alternative sources of thiocyanate in various thiocyanation reactions.

“CHEMISTRY IS THE MOST INTERESTING SCIENCE” <i>ON THE 120TH ANNIVERSARY OF THE BIRTH OF ACADEMICIAN B.A. ARBUZOV</i>

The article is devoted to the life and work of Academician Boris Alexandrovich Arbuzov (1903–1991). He entered the history of Russian science not only as an outstanding scientist, teacher, public figure, but also as a continuer of the traditions of the Kazan Chemical School, who gave her more than 60 years of life. B.A. Arbuzov is the author of classical works in the field of organic chemistry, heterocycle chemistry, organophosphorus compounds, natural compounds – terpenes, as well as polymer chemistry. A special aspect of his scientific work is the application of physical and physico-chemical methods in chemical research. In our country, Watermelon is rightfully considered the founder of the research of fine details of the spatial structure (conformational analysis) of organic and organoelement compounds.

Construction of Bibenzothiophenes through Oxidative C–H Cyclization with 1,3-Diynes

AbstractThe development of concise and efficient methods to construct bithiophene derivatives is an appealing task in the fields of organic chemistry and organic functional materials. Herein, we summarize our recent efforts towards the development of catalytic oxidative C–H cyclization reactions of thiophenol derivatives with 1,3-diynes, which provides a straightforward and effective synthetic approach to both symmetrical and nonsymmetrical 3,3′-bibenzothiophenes. This work is expected to stimulate the application of catalytic oxidative C–H annulation of aromatics with 1,3-diynes for the exploitation of organic functional materials.

Transition-Metal-Catalyzed C-C Bond Formation from C-C Activation.

ConspectusC-C single bonds are ubiquitous in organic compounds. The activation and subsequent functionalization of C-C single bonds provide a unique opportunity to synthesize conventionally inaccessible molecules through the rearrangement of carbon skeletons, often with a favorable atom and step economy. However, the C-C bonds are thermodynamically and kinetically inert. Consequently, the activation of C-C bonds is particularly attractive yet challenging in the field of organic chemistry. In the past decade, we sought to develop efficient strategies to carry out transition-metal-catalyzed diverse C-C cleavage/C-C forming reactions and to obtain some insights into the intrinsic reactivities of different C-C bonds. With our efforts, readily available alcohols, carboxylic acids, and ketones served as suitable substrates for the catalytic C-C coupling reactions, which are reviewed in this Account. In 2009, we observed a Ni-catalyzed cross coupling of aryl nitriles with arylboronic esters through C-CN cleavage. Encouraged by these results, we are interested in transition-metal-catalyzed C-C bond activation. Due to their broad availability, we then turned our attention to C-C cleavage of carboxylic acids. Rhodium-catalyzed decarbonylative coupling of carboxylic acids with (hetero)arenes was then achieved through oxidative addition of in situ formed, more reactive mixed anhydrides to Rh(I) without the need for oxidants that are commonly required for the decarboxylative coupling of carboxylic acids. Subsequently, the decarbonylation of more challenging unstrained aryl ketones was realized under Rh catalysis assisted by N-containing directing groups. Following this work, a group exchange of aryl ketones with carboxylic acids was achieved through 2-fold C-C bond cleavage. By employing the chelation strategy, Rh-catalyzed C-C bond activation of secondary benzyl alcohols was also accomplished through β-carbon elimination of the rhodium alcoholate intermediates. The competing oxidation of secondary alcohols to ketones via β-hydrogen elimination of the same intermediates was suppressed as thermodynamically favorable five-membered rhodacycles are formed after β-carbon elimination. Different types of transformations of alcohols, including the Heck-type reaction with alkenes, cross coupling with arylsilanes, and Grignard-type addition with aldehydes or imines, have been achieved, showing the great potential of secondary alcohols in the formation of C-C bonds. These C-C bond-forming reactions are complementary to traditional cross couplings of aryl halides with organometallic reagents. However, these transformations produce small molecules as byproducts. To improve the atom economy, we then investigated C-C bond transformations of strained-ring cyclic compounds. Ni-catalyzed intermolecular cyclization of benzocyclobutenones with alkynes was recently achieved via the uncommon cleavage of the C1-C8 bond by employing a removable blocking strategy. Rh-catalyzed intramolecular annulation of benzocyclobutenols with alkynes was also achieved. In summary, our developments demonstrate the great potential of transition-metal-catalyzed C-C bond activation for the formation of new C-C bonds. To further expand the synthetic utility of C-C bond activation, more efforts are required to expand the substrate scope and to achieve earth-abundant metal-catalyzed transformations.

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp3)-H to construct C-C bonds.

Ether derivatives are widespread as essential building blocks in various drugs, natural products, agrochemicals, and materials. Modern economy requires developing green strategies with improved efficiency and reduction of waste. Due to its atom and step-economy, the cross-dehydrogenative coupling (CDC) reaction has become a major strategy for ether functionalization. This review covers C-H/C-H cross-coupling reactions of ether derivatives with various C-H bond substrates via non-noble metal catalysts (Fe, Cu, Co, Mn, Ni, Zn, Y, Sc, In, Ag). We discuss advances achieved in these CDC reactions and hope to attract interest in developing novel methodologies in this field of organic chemistry.

Organocatalytic C-H Bond Functionalizations for the Synthesis of Heterocycles

Abstract: Organocatalysis is an important and rapidly growing area for the synthesis of various organic molecules. Because of the inherent non-metal properties, mild reaction conditions, and broad functional group tolerance, the use of small organic compounds encoding and converting another organic component has developed into a remarkable process. C–H activation reactions, on the other hand, have already emerged as a powerful strategy for forming C–C and C–X (X= N, O, S) bonds. Combining organocatalysis and C-H bond functionalization is highly rational as two coexisting and rapidly growing research fields in modern synthetic chemistry, and the cooperative strength along this consistent has proven to be a successful way of making C-H bond functionalization much more feasible, reliable, and specific. At the same time, the synthesis of heterocyclic compounds is an important field in organic chemistry due to the vast application of heterocycles in pharmaceuticals, polymers, and material science. This mini-review describes the recent developments in the synthesis of heterocyclic compounds through the alliance of organocatalysis and C-H bond functionalizations.

State of the Art and Outlook of Data Science and Machine Learning in Organic Chemistry

Abstract: Data Science and Machine Learning approaches have recently expanded to accelerate the discovery of new materials, drugs, synthetic substances and automated compound identification. In the field of Organic Chemistry, Machine Learning and Data Science are commonly used to predict biological and physiochemical properties of molecules and are referred to as quantitative structure–active relationship (QSAR, for biological properties) and quantitative structure– property relationship (QSPR, for nonbiological properties). Data Science and Machine Learning applications are rapidly growing in chemistry and have been successfully applied to the discovery and optimization of molecular properties, optimization of synthesis, automated structure elucidation, and even the design of novel compounds. The main strength of Data Science tools is the ability to find patterns and relationships that even an experienced researcher may not be able to find, and research in chemistry can benefit from. Moreover, this interdisciplinary field is playing a central role in changing the way not only organic chemistry but also how chemistry is done. As cutting-edge ML tools and algorithms such as tensors, natural language processing, and transformers become mature and reliable by chemists. ML will be a routine analysis in a chemistry laboratory like any other technique or equipment.

Use of Biomass Glycerol as a Reducing Agent for Photocatalytic Deprotection of Pyridine N-Oxides in an Aqueous Suspension of Titanium(IV) Oxide.

Deprotection of pyridine N-oxides under mild conditions with an inexpensive and environmentally friendly reducing reagent is an important chemical procedure. The use of biomass waste as the reducing reagent, water as the solvent and solar light as the energy source is one of the most promising approaches with minimal impact on the environment. Therefore, a TiO2 photocatalyst and glycerol are suitable components of this type of reaction. Stoichiometric deprotection of pyridine N-oxide (PyNO) with a minimal amount of glycerol (PyNO:glycerol= 7 : 1) was achieved, with only CO2 being produced as the final oxidation product of glycerol. The deprotection of PyNO was thermally accelerated. Under solar light, the temperature of the reaction system increased to 40-50 °C and PyNO was also quantitatively deprotected, indicating that solar energy, i. e., UV light and thermal energy, can be effectively used. The results provide a new approach in the fields of organic chemistry and medical chemistry using biomass waste and solar light.

Healthcare Environmental Footprint: Proposal to Deliver Sustainability through an Innovative Value Stream Using a Circular Economy Approach

Abstract Over the last 10 years, the most recent innovations in the field of organic chemistry have been significantly driven by both industry needs and environmental concerns. On the former, industrial applications and production processes have evolved to reduce carbon footprint and to reduce the reliance on oil-based organic material precursors. On the latter, increasing concerns around accelerated global warming, have kindled the search for solutions, including lower carbon footprint, recyclability, and upcycling of novel materials. To 2015, the healthcare industry accounted for about 5.7% of the carbon emission with a severe impact in carbon, SO2, Nitrogen and particulate matter. Specifically, what relates to greenhouses, the global contribution accounts to 24 Gton of CO2, which has largely increased due the immense use of disposable devices during the pandemic. Current evidence points towards a substantial interest in the reduction of carbon footprint in the healthcare settings, yet with limited success across the largest health care providers. This study approaches the topic from a literature review and an empirical approach based on previous and ongoing research on the field of additive manufacturing and the use of bio-based materials for medical devices applications, which has been conducted utilizing mechanical, economic and microbiological assessments to address the research question of how to better address the carbon footprint of the healthcare industry, limited to some surgical procedures. This research points towards the direction that the implementation of an on-site solution may help to address some of the sustainability challenges healthcare facilities face while enhancing their circular economy approach. This research is intended to pave the way for further research including specific research to enhance the understanding of the solutions and how these may fit the current regulatory landscape.

A [Dy2] complex with single-molecule magnet behavior and its analogues based on transformed ligand induced by methanol in coordination process

Three [Ln2] complexes, [Ln2(dbm)4(L′)2] (Ln = Tb(1), Dy(2), Ho(3)), were synthesized, and structurally and magnetically analysed. The structural analysis revealed that a rare ligand-transformation in the field of organic chemistry and coordination chemistry occured during the coordination process, where the original Schiff-base ligand HL (2-[[(1,2,4-triazole)-4-imino]methyl]-8-hydroxy-quinoline) was transformed to coordinated ligand HL′ (methyl-8-hydroxyquinoline-2-carboxylate). Static and dynamic magnetic analysis of 1–3 demonstrated single-molecule magnet (SMM) behavior for complex 2 with effective energy barrier of 61.7 K at zero dc field.