Organic Chemistry Research Articles

Key Points, Pain Points and Release Points in the Teaching of Organic Chemistry for Traditional Chinese Medicine Specialties in the Ethnic Areas of Southwest China

Key Points, Pain Points and Release Points in the Teaching of Organic Chemistry for Traditional Chinese Medicine Specialties in the Ethnic Areas of Southwest China

Asymmetric Carbene Transfer: Enhancing Chemical Diversity for Drug Discovery.

The exploration of chemical space for disease targets is of paramount importance. However, the current repertoire of chemically synthesized compounds, numbering around 108, merely scratches the surface in comparison to the theoretical diversity of 1060. Organic chemists are actively engaged in pioneering methodologies to expand this constrained space. Among these innovative approaches, Asymmetric Carbene Transfer (ACT) emerges as a potent strategy for enhancing molecular diversity. This article critically examines the efficacy of ACT in synthesizing pharmaceutically relevant molecules, encompassing natural products and bioactive compounds. We highlight its pivotal role in the synthesis of 25 compounds. By unraveling the diverse applications of ACT, this review illuminates its potential impact on drug discovery. Furthermore, we propose future methodology directions, contributing to the ongoing discourse within the medicinal chemistry community. In summary, this review article navigates the landscape of ACT, showcasing its prowess in expanding chemical space for drug discovery. Through a nuanced exploration of its applications and a forward-looking approach, we contribute to the collective understanding of ACT's potential and chart a course for future advancements in ACT for drug discovery.

Stable Electron Spin Pan on Aromatic Oxalic Acid Radical

Comprehensive SummaryThe stability of organic radicals in ambient condition is important for their practical application. During the development of organic radical chemistry, the electron‐withdrawing and steric hindrance groups are usually introduced to improve the stability of radicals via reducing the reactivity of radicals with oxygen in air. Herein, the electron‐withdrawing carbonyl groups are introduced to construct a planar aromatic oxalic acid radical (IDF‐O8) with two‐dimensional electron spin pan structure. Interestingly, IDF‐O8 exhibited a low optical bandgap of 0.91 eV in film, however, the multiple quinone resonance structures between electron‐withdrawing ketone and phenol radicals contribute to the high stability of open‐shell radical IDF‐O8 without protection of large steric hindrance groups. Under the irradiation of 808 nm (1.2 W·cm–2), IDF‐O8 reaches 147 °C in powder state. This work provides an efficient synthesis route for the open‐shell electron spin pan system, which is different from the famous fullerene, carbon nanotube and graphene. The electron spin pan can be extended to spin tube or spin sphere system based on the design strategy of aromatic inorganic acid radicals in future.

Recent Developments in the Ruthenium‐Catalyzed Azide Alkyne Cycloaddition (RuAAC) Reaction

The ruthenium‐catalyzed azide alkyne cycloaddition (RuAAC) gives access to 1,5‐disubstitued triazoles in a single atom‐economical step and offers advantages compared to its copper‐catalyzed counterpart in that both terminal and internal alkynes can be employed. This review summarized recent findings in this field during the last eight years, covering mechanistic investigations, synthetic developments, as well as applications in medicinal chemistry, polymer synthesis and physical organic chemistry

Insight into the Stability of Pentazolyl Derivatives based on Covalent Bond.

Pentazole is regarded as a unique inorganic molecule that possess organic heterocyclic structure. Therefore, the research on pentazolyl derivatives represents a cutting-edge direction in both contemporary inorganic chemistry and heterocyclic chemistry. Moreover, their synthesis is regarded as the most significant research topic in the field of energetic materials due to the great potential of pentazolyl derivatives to breakthrough the energy bottleneck of CHNO-based energetic materials. However, synthesizing pentazolyl derivatives is challenging. To provide a theoretical support for the synthesis, we conducted theoretical studies on six single-ring pentazolyl derivatives with different functional groups. The results suggest that derivatization reduces the bond strength and weakens the aromaticity of the pentazolate ring. Further analysis showed that derivatization mainly affects the π aromaticity of the pentazolate ring, and ultimately causing poor stability of the pentazolyl derivatives. Among the six derivatives investigated in this study, fluoro pentazole (cyclo-N5-F) and hydroxyl pentazole (cyclo-N5-OH) possess good aromaticity, which is similar to the reported cyclo-N5-NCHN(CH3)2. Further calculations show that the kinetic stability of cyclo-N5-OH is higher than that of cyclo-N5-F. These results collectively indicate that cyclo-N5-OH is a promising candidate for synthesizing single-ring pentazolyl derivatives.

Advancing Pore‐Space‐Partitioned Metal‐Organic Frameworks with Isoreticular Cluster Concept

Trigonal planar M3(O/OH) trimers are among the most important clusters in inorganic chemistry and are the foundational features of multiple high‐impact MOF platforms. Here we introduce a concept called isoreticular cluster series and demonstrate that M3(O/OH), as the first member of a supertrimer series, can be combined with a higher hierarchical member (double‐deck trimer here) to advance isoreticular chemistry. We report here an isoreticular series of pore‐space‐partitioned MOFs called M3M6pacs made from co‐assembly between M3 single‐deck trimer and M3x2 double‐deck trimer. Important factors were identified on this multi‐modular MOF platform to guide optimization of each module, which enables the phase selection of M3M6pacs by overcoming the formation of previously‐always‐observed same‐cluster phases. The new pacs materials exhibit high surface area and high uptake capacity for CO2 and small hydrocarbons, as well as selective adsorption properties relevant to separation of industrially important mixtures such as C2H2/CO2 and C2H2/C2H4. Furthermore, new M3M6pacs materials show electrocatalytic properties with high activity.

Advancing Pore-Space-Partitioned Metal-Organic Frameworks with Isoreticular Cluster Concept.

Trigonal planar M3(O/OH) trimers are among the most important clusters in inorganic chemistry and are the foundational features of multiple high-impact MOF platforms. Here we introduce a concept called isoreticular cluster series and demonstrate that M3(O/OH), as the first member of a supertrimer series, can be combined with a higher hierarchical member (double-deck trimer here) to advance isoreticular chemistry. We report here an isoreticular series of pore-space-partitioned MOFs called M3M6pacs made from co-assembly between M3 single-deck trimer and M3x2 double-deck trimer. Important factors were identified on this multi-modular MOF platform to guide optimization of each module, which enables the phase selection of M3M6pacs by overcoming the formation of previously-always-observed same-cluster phases. The new pacs materials exhibit high surface area and high uptake capacity for CO2 and small hydrocarbons, as well as selective adsorption properties relevant to separation of industrially important mixtures such as C2H2/CO2 and C2H2/C2H4. Furthermore, new M3M6pacs materials show electrocatalytic properties with high activity.

How Much? How Fast? A Study of Kinetics and Thermodynamics through the Lens of Reaction Coordinate Diagrams in Organic Chemistry

How Much? How Fast? A Study of Kinetics and Thermodynamics through the Lens of Reaction Coordinate Diagrams in Organic Chemistry

Recent Advances in the Synthesis of Rosettacin

Camptothecin and its analogues show important antitumor activity and have been used in clinical studies. However, hydrolysis of lactone in the E ring seriously attenuates the antitumor activity. To change this situation, aromathecin alkaloids are investigated in order to replace camptothecins. Potential antitumor activity has obtained more and more attention from organic and pharmaceutical chemists. As a member of the aromathecin alkaloids, rosettacin has been synthesized via different methods. This review summarizes recent advances in the synthesis of rosettacin.

A better representation of volatile organic compound chemistry in WRF-Chem and its impact on ozone over Los Angeles

Abstract. The declining trend in vehicle emissions has underscored the growing significance of volatile organic compound (VOC) emissions from volatile chemical products (VCPs). However, accurately representing VOC chemistry in simplified chemical mechanisms remains challenging due to its chemical complexity including speciation and reactivity. Previous studies have predominantly focused on VOCs from fossil fuel sources, leading to an underrepresentation of VOC chemistry from VCP sources. We developed an integrated chemical mechanism, RACM2B-VCP, that is compatible with WRF-Chem and is aimed at enhancing the representation of VOC chemistry, particularly from VCP sources, within the present urban environment. Evaluation against the Air Quality System (AQS) network data demonstrates that our model configured with RACM2B-VCP reproduces both the magnitude and spatial variability of O3 and PM2.5 in Los Angeles. Furthermore, evaluation against comprehensive measurements of O3 and PM2.5 precursors from the Reevaluating the Chemistry of Air Pollutants in California (RECAP-CA) airborne campaign and the Southwest Urban NOx and VOC Experiment (SUNVEx) ground site and mobile laboratory campaign confirm the model's accuracy in representing NOx and many VOCs and highlight remaining biases. Although there exists an underprediction in the total VOC reactivity of observed VOC species, our model with RACM2B-VCP exhibits good agreement for VOC markers emitted from different sectors, including biogenic, fossil fuel, and VCP sources. Through sensitivity analyses, we probe the contributions of VCP and fossil fuel emissions to total VOC reactivity and O3. Our results reveal that 52 % of the VOC reactivity and 35 % of the local enhancement of MDA8 O3 arise from anthropogenic VOC emissions in Los Angeles. Significantly, over 50 % of this anthropogenic fraction of either VOC reactivity or O3 is attributed to VCP emissions. The RACM2B-VCP mechanism created, described, and evaluated in this work is ideally suited for accurately representing ozone for the right reasons in the present urban environment where mobile, biogenic, and VCP VOCs are all important contributors to ozone formation.

Investigating the Impact of RAMP-Based Safety Instruction on Student Learning in an Organic Chemistry Lab Course

Investigating the Impact of RAMP-Based Safety Instruction on Student Learning in an Organic Chemistry Lab Course

Redox- and Charge-State Dependent Trends in 5, 6, and 7-Membered Boron Heterocycles: A Neutral Ligand Coordination Chemistry Approach to Boracyclic Cations, Anions, and Radicals.

ConspectusBoron heterocycles represent an important subset of heteroatom-incorporated rings, attracting attention from organic, inorganic, and materials chemists. The empty pz orbital at the boron center makes them stand out as quintessential Lewis acidic molecules, also serving as a means to modulate electronic structure and photophysical properties in a facile manner. As boracycles are ripe for extensive functionalization, they are used in catalysis, chemical biology, materials science, and continue to be explored as chemical synthons for conjugated materials and reagents. Neutral boron(III)-incorporated polycyclic molecules are some of the most studied types of boracycles, and understanding their redox transformations is important for applications relying on electron transfer and charge transport. While relevant redox species can often be electrochemically observed, it remains challenging to isolate and characterize boracycles where the boron center and/or polycyclic skeleton have been chemically reduced.We describe our recent work isolating 5-, 6-, and 7-membered boracyclic radicals, anions, and cations, focusing on stabilization strategies, ligand-mediated bonding situations, and reactivity. We present a versatile neutral ligand coordination chemistry approach that permits the transformation of boracycles from potent electrophiles to powerful nucleophilic heterocycles that facilitate diverse electron transfer and bond activation chemistry. Although there are a wide range of suitable stabilizing ligands, we have employed both diamino-N-heterocyclic carbenes (NHCs) and cyclic(alkyl)(amino) carbenes (CAACs), which led to boracycles with tunable electronic structures and aromaticity trends. We highlight successful isolation of borafluorene radicals and demonstrate their reversible redox behavior, undergoing oxidation to the cation or reduction to the anion. The borafluorene anion is a chemical synthon that has been used to prepare boryl main-group and transition-metal bonds, luminescent oxabora-spirocycles, borafluorenate-crown ethers, and CO-releasing molecules via carbon dioxide activation. We expanded to 6-membered boracycles and characterized neutral bis(NHC-supported 9-boraphenanthrene)s and the corresponding bis(CAAC-stabilized 9-boraphenanthrene) biradical. We detail the interconvertible multiredox states of boraphenalene, where the boraphenalenyl radical, anion, and cation mimic the charge-states of the all-hydrocarbon analogue. Reactivity studies of the boraphenalenyl anion displayed unusual nucleophilic reactivity at multiple sites on the periphery of the boraphenalenyl tricyclic scaffold. Reduced borepins, 7-membered boron containing heterocycles, have also been isolated. We used a stepwise one-pot synthesis combining the halo-borepin precursor, CAAC, and KC8 to afford the monomeric borepin radicals and anions. The π-system was extended to contain two borepin rings fused in a pentacyclic scaffold, which permitted isolation of diborepin biradicals and a diborepin containing a dibora-quinone core.Our goal is to provide a guide explaining the current structure-function trends and isolation strategies for redox-active boron-incorporated polycyclic molecules to initiate the rational design and use of these types of compounds across a vast chemical space.

Advances in the Synthesis of Bioorthogonal Reagents: s-Tetrazines, 1,2,4-Triazines, Cyclooctynes, Heterocycloheptynes, and trans-Cyclooctenes.

Aligned with the increasing importance of bioorthogonal chemistry has been an increasing demand for more potent, affordable, multifunctional, and programmable bioorthogonal reagents. More advanced synthetic chemistry techniques, including transition-metal-catalyzed cross-coupling reactions, C-H activation, photoinduced chemistry, and continuous flow chemistry, have been employed in synthesizing novel bioorthogonal reagents for universal purposes. We discuss herein recent developments regarding the synthesis of popular bioorthogonal reagents, with a focus on s-tetrazines, 1,2,4-triazines, trans-cyclooctenes, cyclooctynes, hetero-cycloheptynes, and -trans-cycloheptenes. This review aims to summarize and discuss the most representative synthetic approaches of these reagents and their derivatives that are useful in bioorthogonal chemistry. The preparation of these molecules and their derivatives utilizes both classical approaches as well as the latest organic chemistry methodologies.

Major structural types in inorganic chemistry and mineralogy: New data

Research subject. Structural types with different stoichiometric correlations between chemical elements. Aim. To analyze the prevalence of structural types with different stoichiometric correlations between chemical elements, such as simple substances with binary compounds, triple compounds with stoichiometry ABX3, triple compounds with stoichiometry AB2X4. Key points. The analysis was conducted using the databases of inorganic compounds ICSD (Inorganic Crystal Structure Database) and PCD (Pearson’s Crystal Data). The number of entries with the most typical structural types for 2013 and 2023 are determined. Their classifications in various databases for different years are given. The ranks of structural types for minerals and inorganic compounds are analyzed. The minerals crystallized in all the considered structural types are indicated according to the 2023 ISCD data, sampling only by the number of minerals registered in IMA (International Mineralogical Association – Commission on New Minerals, Nomenclature and Classification) for March 2023. The Russian names of minerals are presented in accordance with the database WWW-MINCRIST for the minerals crystallizing in all the structural types under consideration. Conclusions. The most probable causes for the realization of each stoichiometric correlation in various structural types are determined. The prevalence of certain structural types among inorganic compounds and minerals, as well as the underlying reasons, are discussed based on the principles of crystal chemistry.

Quinoline based viologen as a multifunctional organic material – From crystal structures to photophysical and electrochemical properties, and application in DNA sensing and bioimaging

Developing new multifunctional organic materials is one of the current themes of research in organic materials chemistry. The class of N,N'-dialkylated bis-pyridinium compounds, namely, the viologens have been proven to offer such multifunctional materials. Herein, syntheses and crystal structure elucidation of trans-1,2-bis(4-quinolinyl)ethylene (BQE) and analogous N,N-dimethylated trans-1,2-bis(4′-quinolinium)ethylene (M2BQE) are discussed with their multifaceted materials properties. Two different crystal structures with significantly different molecular structures, namely, BQE and BQE⋅2H2O were obtained by tuning the solvent of crystallization. M2BQE showed a bathochromic shift both in its absorption by ∼ 3300 cm−1 and in emission by ∼2900 cm−1 in compared to BQE, which is the effect of quaternization. Large Stokes shifts were observed for both the BQE (∼8500 cm−1) and M2BQE (∼8050 cm−1). Both compounds showed two-step reduction events in cyclic voltammetry, of which the first steps were reversible. The pH dependent absorption and emission properties of BQE have been explored which revealed the stronger effect by methylation than protonation. M2BQE exhibited selective binding to ct-DNA, as confirmed by selective quenching of emission intensity, over AMP and ATP. Furthermore, both the BQE and M2BQE displayed very intriguing features in bioimaging by intracellular co-localization in HeLa cells. While BQE is predominantly localizes in lysosomes over mitochondria, M2BQE dication, on the other hand, explicitly localizes in mitochondria.

Cascade Sequence of Photooxygenation-Epoxidation for the Flow Synthesis of Epoxy Alcohols.

A photooxygenation-epoxidation cascade sequence converting alkenes to epoxy alcohols was developed and evaluated in batch and continuous-flow systems. In the batch system, the undesired interactions between the photooxygenation and epoxidation catalysts resulted in suboptimal yields, whereas the fine control of reaction parameters in the flow system allowed the allyl hydroperoxides produced through photooxygenation of alkenes to be rapidly converted to epoxy alcohols in yields of up to 93%. The developed procedure allows one to avoid an important synthetic bottleneck, works well where traditional batch synthesis fails, and can be scaled up to meet the needs of industrial production, thus presenting a valuable addition to the toolbox of practicing organic chemists.

Bridging chemistry education research and practice through research-practice partnerships

This perspective article is a call to establish research-practice partnerships (RPPs) to foster collaborations between instructors and education researchers to tune into the needs of practice, share evidence-based practices, and solve modern organic chemistry education problems. I begin the article by discussing some limitations of the traditional approach of “translating” research into practice and suggest RPPs as an alternative model for “bridging” research and practice. Importantly, RPPs have been shown to address persistent problems of practice and improve educational outcomes. While more common at the secondary level, RPPs are rarely leveraged in post-secondary chemistry education. The article goes on to provide a concrete and relevant context for potential future RPP efforts to improve aspects of organic chemistry education—RPPs between education researchers and organic chemistry instructors to work toward designing, administering, and testing interventions to support learners’ representational competence (RC). RC is a set of skills that allow for the reflective use of a variety of representations to think about, communicate, and act on chemical phenomena. Current instruction often falls short of effectively supporting learners in developing RC. It is often tacitly assumed that learners will develop RC without explicit instruction that scaffolds the development of the RC skills. While it is important to improve the teaching about and with representations, implementing innovative pedagogical approaches can be challenging, particularly when instructors feel isolated in their efforts within their work environments. The RPP model could catalyze solutions to these challenges by pooling diverse expertise, thus enabling more robust and sustainable educational innovations.

The synergistic effect of typical chiral organic acids and solution chemistry conditions on the transport of 2-arylpropionic acid chiral derivatives in porous media

The hazards of man-made chiral compounds are of great public concern, with reports of worrying stereoselective compounds and an urgent need to assess their transport. This study evaluated the transport of 2-arylpropionic acid derivatives enantiomers (2-APA) in porous media under a variety of solution chemistry conditions via column packing assays. The results revealed the introduction of Malic acid (MA) enantiomers enhanced the mobility of 2-APA enantiomers, but the enhancement effect was different for different 2-APA enantiomers. Batch sorption experiments confirmed that the MA enantiomers occupied the sorption site of the quartz sand, thus reducing the deposition of the 2-APA enantiomer. Homo- or heterochirality between 2-APA and MA dominates the transport of 2-APA enantiomers, with homochirality between them triggering stronger retention and vice versa. Further evaluating the effect of solution chemistry conditions on the transport of 2-APA enantiomers, increased ionic strength attenuated the mobility of 2-APA enantiomers, whereas introduced coexisting cations enhanced the retention of 2-APA enantiomers in the column. The redundancy analyses corroborated these solution chemistry conditions were negatively correlated with the transport of 2-APA enantiomers. The coupling of pH and these conditions reveals electrostatic forces dominate the transport behavior and stereoselective interactions of 2-APA enantiomers. Distinguishing the transport of enantiomeric pair helps to understand the difference in stereoselectivity of enantiomers and promises to remove the more hazardous one.

Synthesis, Structure-activity Relationship, and Biological Activity of Benzimidazole-quinoline: A Review to Aid in the Design of a New Drug

Abstract: Heterocyclic compounds are fundamental building blocks for developing novel bioactive compounds. Due to their extensive uses in both industrial and synthetic organic chemistry, quinoline and benzimidazole have recently become important heterocycles. Clinical trials have investigated quinoline and benzimidazole analogues to treat a variety of illnesses, including cancer, bacterial and fungal infection, DNA damage, etc. Medicinal chemists are paying attention to nitrogen-containing hybrid heterocyclic compounds that have a wide range of therapeutical potential with lesser adverse effects. Many efforts have been made to find new and more efficient ways to synthesize these molecules. However, microbial resistance is becoming a major threat to the scientific community; hence, the necessity for the discovery and development of novel antimicrobial drugs with novel modes of action is becoming highly significant. One strategy to overcome this problem is to produce hybrid molecules by combining two or more bioactive heterocyclic moieties in a single molecular platform. Based on established research data on quinoline- bearing benzimidazole derivatives, it can be concluded that both moieties are used for the synthesis of promising therapeutically active agents. This present review comprises the synthetic approaches of biologically active quinolines containing benzimidazole derivatives with their structure-activity relationship studies to provide an overview of the work done on quinoline derivatives to the medicinal chemist for future research.

Preface for the special issue “New trends in inorganic chemistry: A special issue in honor of professor Howard Alper”

Preface for the special issue “New trends in inorganic chemistry: A special issue in honor of professor Howard Alper”