Organic Chemistry Research Research Articles

An account of organic chemistry research in Botswana

An account of organic chemistry research in Botswana

A Study on Aromatic Heterocyclic Organic Compounds

The synthesis of newer and more novel molecules has always been a goal for research in organic chemistry. Heterocyclic compounds are those in which the fundamental compound structure contains an element other than carbon. These molecules may also be aromatic, which means they have a distinct odor. The composition of heterocyclic compounds will be discussed in depth in this study. The paper will also go through the synthesis and application methodologies. The pharmaceutical sector makes substantial use of these chemicals. It is largely employed in histamine and serotonin-related medications in that country. These chemicals are also used in the cosmetics and DNA vaccine industries, as well as in genetic research. Advancements in organic chemistry are allowing for a more thorough investigation of aromatic heterocyclic compounds in order to get a better knowledge of their structural and chemical compatibility with other molecules.

Recent Progress in the Selective Fluorinations of Some Functionalized Cycloalkenes

AbstractOrganofluorine compounds have had an increasing impact in synthetic organic chemistry and pharmaceutical research over the past two decades. Their syntheses and the development of novel synthetic approaches towards versatile fluorinated small molecules have received great interest. Our research team has designed various selective and stereocontrolled methods for the construction of fluorine‐containing small molecular entities, involving the transformation of various functionalized cycloalkenes across their ring olefin bond. The synthetic methodologies developed to access various pharmacologically interesting fluorinated derivatives with multiple chiral centers might be valuable protocols for the preparation of other classes of organic compounds as well.

Model Synthetic Study of Tutin, a Picrotoxane-Type Sesquiterpene: Stereoselective Construction of a cis-Fused 5,6-Ring Skeleton.

Picrotoxinin, coriamyrtin, and tutin are representative natural products classified as picrotoxane-type sesquiterpenes and they function as strong neurotoxins. Because they possess a cis-fused 5,6-ring skeleton with a highly congested functionalization, organic chemistry researchers have pursued the development of a stereoselective synthesis method for such skeleton. This study aims to stereoselectively synthesize the cis-fused 5,6-ring skeleton with two tetrasubstituted carbons at both angular positions using a model compound. The results revealed that the desymmetrization of the 2-methyl-1,3-cyclopentanedione moiety via the DL-proline-mediated intramolecular aldol reaction of a pentanal derivative bearing an isopropenyl group and the five-membered ring at the 3- and 5-position, respectively, provided the desired cis-fused skeleton. This reaction can construct four contiguous stereogenic centers of the bicyclic skeleton with the two angular positions in good yield with high stereoselectivity. Further, this reaction was applied to the kinetic resolution of the racemate using L-proline, providing the enantiomeric pure aldol product with the desired skeleton. This method can be utilized for total synthesis of picrotoxane-type sesquiterpenes.

Recent Development of Heterocyclic Compounds with Indazole Moiety as Potential Antiparasitic Agents.

Indazole is a vital nitrogen-containing heterocyclic unit in organic and medicinal chemistry research and a helpful precursor molecule for the production of various types of encirclement heterocycles. Indazole analogues are diverse pharmacological agents that can be used to treat a variety of conditions, including cancer, inflammation, infectious diseases, and neurological problems. In fact, the indazole moiety containing inhibitors also showed excellent medicinal properties for the treatment of parasitic diseases. Therefore, the development of new inhibitors has immense promise for usage as key components for the next generation of antiparasitic medication. In this review, we have summarized the recent developments of indazole-containing antiparasitic inhibitors, specially anti-protozoal, anti-fungal, and antiamoebic inhibitors, as well as their structure-activity relationship (SAR) findings for medicinal chemists who are searching for new preclinical parasitic drug candidates.

Regioselectivity in the reaction of 5-amino-3-anilino-1H-pyrazole-4-carbonitrile with cinnamonitriles and enaminones: Synthesis of functionally substituted pyrazolo[1,5-a]pyrimidine derivatives

Abstract The development of efficient methods for the synthesis of polyfunctional N-heterocycles is an important area of research in organic and medicinal chemistry. Pyrazolo[1,5-a]pyrimidine derivatives are purine analogous of biomedical importance and have been extremely studied for their broad spectrum of biological activities. Recently, they have attracted great interest in materials science owing to their photophysical properties. 3(5)-Aminopyrazoles are extensively utilized in the synthesis of condensed heterocyclic systems, particularly pyrazolo[1,5-a]pyrimidines via the reaction with 1,3-biselectrophilic reagents. However, the information available in the literature provides little in the way of reasoning their cyclization, particularly the initial attack either by the exocyclic amino group or endocyclic nitrogen. Unfortunately, the relative nucleophilicity of exo- and endocyclic nitrogen atoms in 1-unsubstituted 3(5)-aminopyrazoles is not clear and contradicting. It has been found that other factors can modulate the regioselectivity rather than basicity or steric hindrance for both active sites. The reported studies in the structure–activity relationship revealed that pyrazolo[1,5-a]pyrimidines having a substitution at fifth, sixth, and seventh positions possess potent biological activities, especially those with an amino group at the seventh position. We here developed a regioselective, high yield synthesis of 7-amino-5-arylpyrazolo[1,5-a]pyrimidine-3,6-dicarbonitriles by the reaction of N-(5-amino-4-cyano-1H-pyrazole-3-yl)-benzamide with various cinnamonitriles and enaminones in pyridine at 120°C under controlled microwave heating conditions. All structures of newly synthesized compounds were established by analytical and spectral data as well as single-crystal diffraction and rationalized for their formation.

Preparation and Study of Copper Peroxide and Copper Oxide for Electrochemical Reduction of CO<sub>2</sub>:Design of a Comprehensive Research Inorganic Chemistry Experiment

Preparation and Study of Copper Peroxide and Copper Oxide for Electrochemical Reduction of CO<sub>2</sub>:Design of a Comprehensive Research Inorganic Chemistry Experiment

Synthesis, Characterization, and Computation of Benzodithienothiadiazole-based Small Molecular Fragments (DT-BTD)

Benzodithienothiadiazoles (DT-BTDs) are a class of small molecular fragments with rigid planar conjugated structures, which are simple and easy to synthesize with high yields. There is currently an essential structure for constructing efficient polymer materials. unit. Synthesis, characterization, and calculation of small molecule fragments based on benzodithienothiadiazole are comprehensive experiments using organic chemistry research methods. This paper aims to improve students' essential operational and analytical ability in organic synthesis to apply experimentally. It is combined with the textbook content to deepen the understanding of the textbook content. In addition, the infrared spectroscopy, ultraviolet spectroscopy, and hydrogen nuclear magnetic resonance spectroscopy of DT-BTD molecules, infrared spectroscopy, and ultraviolet spectroscopy calculations using Gaussian software are supplements to the current undergraduate experimental teaching in computational chemistry. This experiment is conformed to the innovative undergraduate experimental design, which can comprehensively improve undergraduates' experimental literacy. It can broaden their knowledge and cultivate the ability to independently use modern instrumental analysis methods.

Road Map for the Construction of High-Valued N-Heterocycles via Denitrogenative Annulation.

The pursuit for the discovery of new and powerful synthetic methods to access high-value N-heterocycles has been at the forefront of organic chemistry research for more than a century. Considering the importance of N-scaffolds in modern science, over the past few decades, great research efforts have been made to develop efficient synthetic methods for the construction of nitrogen-rich molecules. Among many efforts, transition metal catalyzed denitrogenative annulation reaction has emerged as a cornerstone due to its innate versatility and wider scope of application.The denitrogenative annulation approach offers clear advantages over many existing methods, as it enables effective, single-step interconversion of easily available feedstocks into a variety of other important N-containing heterocyclic frameworks. Recently, transition metal catalyzed denitrogenative annulation reaction of the 1,2,3-triazole via a metal carbene intermediate sparked significant interest in the application of various important heterocycle syntheses. Denitrogenative annulation reaction of 1,2,3-triazoles proceeds via an ionic mechanism. Recently, we demonstrated a new concept for the denitrogenative reaction of triazoles with alkenes and alkynes via in situ generated 2-(diazomethyl)pyridines. The method takes advantage of the inherent properties of a Co(III)-carbene radical intermediate and is the first report of the denitrogenative annulation/cyclopropanation by a radical-activation mechanism.On the other hand, in contrast to the denitrogenative annulation of 1,2,3-triazole, annulation reaction of 1,2,3,4-tetrazole (a surrogate of azide having an important pyridyl unit) via metal nitrene remains a big challenge. Previously, flash vacuum pyrolysis studies had been used for nitrene-nitrene rearrangement of 1,2,3,4-tetrazole at high temperature. This Account summarizes our recent efforts in developing transition metal catalyzed denitrogenative annulation of 1,2,3-triazoles via a radical mechanism and 1,2,3,4-tetrazoles via metal nitrene to access important nitrogen-rich molecules. We demonstrated that the 1,2,3,4-tetrazole under Ir-catalyzed reaction conditions can produce a productive Ir-nitrene intermediate that can successfully be employed for the construction of a wide number of α-carbolines and 7-azaindoles. Moreover, we developed an iron-based unique strategy for the intermolecular denitrogenative annulation reaction between tetrazoles and alkynes. The reaction overcomes the traditional click reaction and proceeds via an unprecedented metalloradical activation mechanism. Furthermore, we used our understanding of tetrazole reactivity to design an iron-catalyzed intramolecular denitrogenative C(sp3)-H amination reaction of primary, secondary, and tertiary centers by using a metalloradical activation concept. At the same time, we also developed a general catalytic method to enable two distinct reactions (1,3-cycloaddition and denitrogenative annulation) using Mn(TPP)Cl that afforded two different classes of nitrogen heterocycles. Mechanistic studies showed that although the click reaction likely proceeds through an ionic mechanism and the denitrogenative annulation reaction likely proceeds via an electrophilic metallonitrene intermediate rather than a metallonitrene radical intermediate. Finally, we report an iron-catalyzed rearrangement reaction (ring expansion/migration) that proceeded with an unprecedented level of selectivity, reactivity, and functional group tolerance offering rapid access to numerous complex N-heterocycles. We believe that our continuous efforts in this field would be beneficial for pharmaceutical industries, drug discovery, and other fields of medicinal chemistry.

Chiral Photocatalyst Structures in Asymmetric Photochemical Synthesis.

Asymmetric catalysis is a major theme of research in contemporary synthetic organic chemistry. The discovery of general strategies for highly enantioselective photochemical reactions, however, has been a relatively recent development, and the variety of photoreactions that can be conducted in a stereocontrolled manner is consequently somewhat limited. Asymmetric photocatalysis is complicated by the short lifetimes and high reactivities characteristic of photogenerated reactive intermediates; the design of catalyst architectures that can provide effective enantiodifferentiating environments for these intermediates while minimizing the participation of uncontrolled racemic background processes has proven to be a key challenge for progress in this field. This review provides a summary of the chiral catalyst structures that have been studied for solution-phase asymmetric photochemistry, including chiral organic sensitizers, inorganic chromophores, and soluble macromolecules. While some of these photocatalysts are derived from privileged catalyst structures that are effective for both ground-state and photochemical transformations, others are structural designs unique to photocatalysis and offer insight into the logic required for highly effective stereocontrolled photocatalysis.

For director-at-large: Lee M. Latimer

California Section. Consultant, LHLatimer Consulting, Oakland, California. Academic record: Tulane University, BS, chemistry, 1971; University of Wisconsin, PhD, organic chemistry, 1976; University of California, Berkeley, postdoctoral research in organic chemistry, 1976–77; University of Wisconsin School of Pharmacy, postdoctoral research in organic chemistry, 1977–79. Honors: ACS Division of Chemical Health and Safety, Howard Fawcett Chemical Health Award, 2016; ACS Santa Clara Valley Section, Shirley B. Radding Award, 2014; ACS Fellow, 2012; ACS California Section, Walter B. Petersen Award, 2010; ACS Rochester Section, Rochester Section Award, 1991; Elan Pharmaceuticals, Chemical Sciences Excellence Award, 2009; Kodak Research Labs, Gold Team Achievement Award, 1992; National Institutes of Health, Postdoctoral Fellowship, 1977–79; Phi Beta Kappa, 1971; Sigma Xi, 1971. Professional positions (for past 10 years): LHLatimer Consulting, drug development consultant, 2011–; NeurOp, head of chemistry, 2014–16; Elan Pharmaceuticals, 1995–2011, senior director of process and analytical chemistry, 2005–11, chemical hygiene officer, 2004–10; San Francisco State University,

Photoinduced Copper-Catalyzed Asymmetric C-O Cross-Coupling.

The construction of carbon-heteroatom bonds is one of the most active areas of research in organic chemistry because the function of organic molecules is often derived from the presence of heteroatoms. Although considerable advances have recently been achieved in radical-involved catalytic asymmetric C-N bond formation, there has been little progress in the corresponding C-O bond-forming processes. Here, we describe a photoinduced copper-catalyzed cross-coupling of readily available oxime esters and 1,3-dienes to generate diversely substituted allylic esters with high regio- and enantioselectivity (>75 examples; up to 95% ee). The reaction proceeds at room temperature under excitation by purple light-emitting diodes (LEDs) and features the use of a single, earth-abundant copper-based chiral catalyst as both the photoredox catalyst for radical generation and the source of asymmetric induction in C-O coupling. Combined experimental and density functional theory (DFT) computational studies suggest the formation of π-allylcopper complexes from redox-active oxime esters as bifunctional reagents and 1,3-dienes through a radical-polar crossover process.

Mechanochemical Synthesis and Reactivity of 1,2,3-Triazole Carbohydrate Derivatives as Glycogen Phosphorylase Inhibitors.

We have developed this work to recommend an original route for the preparation of triazole derivatives. Carbohydrates containing 1,2,3-triazole derivatives have various biological activities. Due to their advantageous and biological property, they are eye-catching synthetic targets in the arsenal of organic chemistry. Thus, finding green and efficient methods, as well as using the ball milling procedure for the synthesis of these heterocycles, is of interest to organic chemistry researchers. The objective of this study was to synthesize carbohydrate-derived triazoles under high-speed vibration milling conditions and investigate their properties. A mixture of glycoside azide derivatives (1 mmol) and prop-2-yn-1-ol (1.5 mmol) in the presence of copper (I) was vigorously shaken under vibration milling conditions at 650 rpm with three balls for 15 min. The deprotection of the resulting triazole derivatives was affected by treatment with 4M hydrochloric acid in methanol under reflux. A short and convenient route to synthesize carbohydrate-derived triazoles, based on a ball-mill via 1,3-dipolar cycloaddition reactions to prop-2-yn-1-ol, was developed. Cleavage of the isopropylidene protecting group provided water-soluble triazoles, evaluated as glycogen phosphorylase inhibitors. 1-[6- (4-Hydroxymethyl-[1,2,3]triazol-1-yl)-2,2-dimethyl-tetrahydro-furo[3,4-d][1,3]dioxol-4-yl]-ethane-1,2-diol was the best inhibitor of rabbit muscle glycogen phosphorylase b (IC50 = 60 μM). In summary, we developed new, short and convenient routes to glucose-derived 1,2,3-triazole based on 1,3-dipolar cycloaddition reactions flowed by ball milling. The use of isopropylidene protective groups gave access to the analogous deprotected water-soluble motifs, analogous to known inhibitors of glycogen phosphorylase.

Titan in a Test Tube: Organic Co-crystals and Implications for Titan Mineralogy.

In this Account, we highlight recent work in the developing field of mineralogy of Saturn's moon Titan, focusing on binary co-crystals of small organic molecules. Titan has a massive inventory of organic molecules on its surface that are formed via photochemistry in the atmosphere and likely processing on the surface as well. Physical processes both in the atmosphere and on the surface can lead to molecules interacting at cryogenic temperatures. Recent laboratory work has demonstrated that co-crystals between two or more molecules can form under these conditions. In the organic-rich environment of Titan, such co-crystals are naturally occurring minerals and a critical area of research to understand the physical, chemical, and possibly even biological and prebiotic processes occurring in this alien world.With a future NASA mission, Dragonfly, slated to land on Titan in the next decade, much work is needed to understand organic mineralogy in order to properly interpret the data from this and past Titan missions, such as Cassini-Huygens. By cataloging Titan minerals and their properties, we can begin to connect these behaviors to large-scale surface features observed on Titan (labyrinth terrain, lake evaporites, karst, dunes, etc.), and possible processes leading to their formation (erosion, deposition, etc.). To date, seven co-crystals (aside from clathrates and hydrates) have been experimentally reported to form under Titan-relevant conditions, with an eighth predicted by theoretical modeling. This Account will summarize the formation and properties of these cryominerals and discuss the implications for surface processes on Titan. Enhanced thermal expansion and decreased crystal size, for example, may lead to fracturing and/or more rapid erosion of co-crystal-based deposits; density changes upon co-crystal formation may also play a role in organic diagenesis and metamorphism on Titan. Some cryominerals with stability only under certain conditions may preserve the evidence of Titan's history, such as cryovolcanic activity, ethane fluvial/pluvial exposure, and outgassing of CO2 from the interior of the moon.In this Account, we will also highlight areas of future work, such as the characterization of pure molecular solids and the search for ternary (and more complex) co-crystals. We note that on Titan, organic chemistry dominates, which gives a unique opportunity for chemists to play an even more significant role in planetary science discoveries and likewise in discoveries motivated by planetary science to inform fundamental organic and physical chemistry research.

Review on Asymmetric Catalysis Employing 5H‐Oxazol‐4‐Ones as α‐Hydroxy Carboxylic Acid Surrogates

AbstractHeterocycles play an essential role in medicinal as well as in organic synthetic chemistry. The synthesis of these valuable scaffolds is an emerging and challenging field of today‘s research in organic chemistry. In recent years, several heterocycles as new synthons have emerged as potential nucleophiles in asymmetric transformations. Among them, 5H‐oxazol‐4‐one is one of the strategic synthons for synthesizing enantioenriched α‐alkyl‐α‐hydroxycarboxylic acid derivatives, which are otherwise very challenging via direct installation of a hydroxy group at the α‐position of carbonyls. Over the years, considerable progress has been made to establish new and efficient methodologies under mild reaction conditions exploiting metal‐ and organo‐catalysis. This review presents a comprehensive summary of various catalytic development in asymmetric synthesis employing 5H‐oxazol‐4‐ones as α‐alkyl‐α‐hydroxycarboxylic acid surrogates.magnified image

Synthesis of Complex Diterpenes: Strategies Guided by Oxidation Pattern Analysis.

With complex molecular architectures, intriguing oxidation patterns, and wide-ranging biological activities, diterpene natural products have greatly impacted research in organic chemistry and drug discovery. Our laboratory has completed total syntheses of several highly oxidized diterpenes, including the ent-kauranoids maoecrystal Z, trichorabdal A, and longikaurin E; the antibiotic pleuromutilin; and the insecticides ryanodol, ryanodine, and perseanol. In this Account, we show how analysis of oxidation patterns and inherent functional group relationships can inform key C-C bond disconnections that greatly simplify the complexity of polycyclic structures and streamline their total syntheses. In articulating these concepts, we draw heavily from the approaches to synthetic strategy that were codified by Evans, Corey, Seebach, and others, based on the formalism that heteroatoms impose an alternating acceptor and donor reactivity pattern upon a carbon skeleton. We find these ideas particularly useful when considering oxidized diterpenes as synthetic targets.In the first part of the Account, we describe the use of reductive cyclizations as strategic tactics for building polycyclic systems with γ-hydroxyketone motifs. We have leveraged Sm-ketyl radical cyclizations as "reactivity umpolungs" to generate γ-hydroxyketones in our total syntheses of the Isodon ent-kauranoid diterpenes (-)-maoecrystal Z, (-)-longikaurin E, and (-)-trichorabdal A. Following this work, we identified the same γ-hydroxyketone pattern in the diterpene antibiotic (+)-pleuromutilin, which again inspired the use of a SmI2-mediated reductive cyclization, this time to construct a bridging eight-membered ring. This collection of four total syntheses highlights how reductive cyclizations are particularly effective umpolung tactics when used to simultaneously form rings and introduce 1,4-dioxygenation patterns.In the second part of the Account, we detail the syntheses of the complex and highly oxidized ryanodane and isoryanodane diterpenes and present the oxidation pattern analysis that guided our synthetic designs. We first discuss our 15-step total synthesis of (+)-ryanodol, which incorporated five of the eight oxygen atoms in just two transformations: a dihydroxylation of (S)-pulegone and a SeO2-mediated trioxidation of the A-ring cyclopentenone. This latter transformation gave rise to an independent investigation of SeO2-mediated peroxidations of simple bicyclic cyclopent-2-en-1-ones. The syntheses of (+)-ryanodine and (+)-20-deoxyspiganthine are also presented, which required modified end-game strategies to selectively incorporate the key pyrrole-2-carboxylate ester. Finally, we describe our fragment coupling approach to prepare the isoryanodane diterpene (+)-perseanol. Using a similar oxidation pattern analysis to that developed in the synthesis of ryanodol, we again identified a two-stage strategy to install the five hydroxyl groups. This strategy was enabled by a Pd-mediated carbopalladation/carbonylation cascade and leveraged unexpected, emergent reactivity to sequence a series of late-stage oxidations.While each of the diterpene natural products discussed in this Account present unique synthetic questions, we hope that through their collective discussion, we provide a conceptual framework that condenses and summarizes the chemical knowledge we have learned and inspires future discourse and innovations in strategy design and methodology development.

Citation Bias in Organic Chemistry Research: Are Industry-Affiliated Papers Cited Less Often?

ADVERTISEMENT RETURN TO ISSUEEditorialNEXTCitation Bias in Organic Chemistry Research: Are Industry-Affiliated Papers Cited Less Often?Kai Rossen*Kai RossenSanofi, 65926 Frankfurt, Germany*Email: [email protected]More by Kai Rossenhttp://orcid.org/0000-0002-3857-0004 and Kali A. MillerKali A. MillerJournals Publishing Group, American Chemical Society, Washington, D.C. 20036, United StatesMore by Kali A. Millerhttp://orcid.org/0000-0003-3632-0615Cite this: Org. Process Res. Dev. 2021, 25, 2, 167–168Publication Date (Web):February 19, 2021Publication History Published online19 February 2021Published inissue 19 February 2021https://doi.org/10.1021/acs.oprd.1c00023Copyright © Published 2021 by American Chemical SocietyRIGHTS & PERMISSIONSArticle Views3027Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (429 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Agrochemicals,Industrial manufacturing,Organic chemistry,Quality management Get e-Alerts

ChemSpectra: a web-based spectra editor for analytical data

ChemSpectra, a web-based software to visualize and analyze spectroscopic data, integrating solutions for infrared spectroscopy (IR), mass spectrometry (MS), and one-dimensional 1H and 13C NMR (proton and carbon nuclear magnetic resonance) spectroscopy, is described. ChemSpectra serves as web-based tool for the analysis of the most often used types of one-dimensional spectroscopic data in synthetic (organic) chemistry research. It was developed to support in particular processes for the use of open file formats which enable the work according to the FAIR data principles. The software can deal with the open file formats JCAMP-DX (IR, MS, NMR) and mzML (MS) proposing these data file types to gain interoperable data. ChemSpectra can be extended to read also other formats as exemplified by selected proprietary mass spectrometry data files of type RAW and NMR spectra files of type FID. The JavaScript-based editor can be integrated with other software, as demonstrated by integration into the Chemotion electronic lab notebook (ELN) and Chemotion repository, demonstrating the implementation into a digital work environment that offers additional functionality and sustainable research data management options. ChemSpectra supports different functions for working with spectroscopic data such as zoom functions, peak picking and automatic peak detection according to a default or manually defined threshold. NMR specific functions include the definition of a reference signal, the integration of signals, coupling constant calculation and multiplicity assignment. Embedded into a web application such as an ELN or a repository, the editor can also be used to generate an association of spectra to a sample and a file management. The file management supports the storage of the original spectra along with the last edited version and an automatically generated image of the spectra in png format. To maximize the benefit of the spectra editor for e.g. ELN users, an automated procedure for the transfer of the detected or manually chosen signals to the ELN was implemented. ChemSpectra is released under the AGPL license to encourage its re-use and further developments by the community.

Cu(II)-grafted 2D-hexagonal mesoporous material as an efficient catalyst for Sonogashira C-C cross-coupling reaction

Abstract Replacing expensive Pd-catalysts by a low cost and sustainable catalytic system is one of the major challenging areas of research in synthetic organic chemistry. Herein, we report a new Cu(II)-anchored mesoporous catalyst (SBA-NH2-L-Cu) by immobilizing Cu(II) over organic ligand (L) anchored amino functionalized mesoporous SBA-15 (SBA-NH2-L) material. SBA-NH2-L-Cu has been characterized by different physicochemical techniques like powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR), high resolution transmission electron microscopy (HRTEM), N2 sorption, X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and thermo-gravimetric analysis (TGA). SBA-NH2-L-Cu has been employed as an efficient heterogeneous catalyst in the Sonogashira C–C cross-coupling reaction for the synthesis of aromatic alkynes in the 1: 1 solvent mixture of 1,4-dioxan and water in the presence of K2CO3 base and very minor amount of Pd/C (5% on active charcoal, 0.25 mol%) as co-catalyst at 80 °C in 4 h reaction time. The catalyst is easy to handle and recycled for several times without any significant loss in catalytic activity.

The Fusion of Basic Organic Chemistry Teaching and Research Frontiers: The Bonding Manner of Covalent Organic Frameworks

The Fusion of Basic Organic Chemistry Teaching and Research Frontiers: The Bonding Manner of Covalent Organic Frameworks