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Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-19 Alexander Zika, Franziska Gröhn
Light- and pH-responsive nano-assemblies with switchable size and structure are formed by the association of a photoacid, anthocyanidin, and a linear polyelectrolyte in aqueous solution. Specifically, anionic disulfonated naphthol derivatives, neutral hydroxyflavylium, and cationic poly(allylamine) are used as building blocks for the ternary electrostatic self-assembly, forming well-defined supramolecular
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Au(III) complexes with tetradentate-cyclam-based ligands Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-19 Ann Christin Reiersølmoen, Thomas N. Solvi, Anne Fiksdahl
Chiral cyclam (1,4,8,11-tetraazacyclotetradecane) derivatives were synthesized stepwise from chiral mono-Boc-1,2-diamines and (dialkyl)malonyl dichloride via open diamide-bis(N-Boc-amino) intermediates (65–91%). Deprotection and ring closure with a second malonyl unit afforded the cyclam tetraamide precursors (80–95%). The new protocol allowed the preparation of the target cyclam derivatives (53–59%)
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Insight into functionalized-macrocycles-guided supramolecular photocatalysis Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-18 Minzan Zuo, Krishnasamy Velmurugan, Kaiya Wang, Xueqi Tian, Xiao-Yu Hu
Due to the unique characteristics of macrocycles (e.g., the ease of modification, hydrophobic cavities, and specific guest recognition), they can provide a suitable environment to realize photocatalysis via noncovalent interactions with different substrates. In this minireview, we emphasized the photochemical transformation and catalytic reactivity of different guests based on the binding with various
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Novel library synthesis of 3,4-disubstituted pyridin-2(1H)-ones via cleavage of pyridine-2-oxy-7-azabenzotriazole ethers under ionic hydrogenation conditions at room temperature Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-18 Romain Pierre, Anne Brethon, Sylvain A. Jacques, Aurélie Blond, Sandrine Chambon, Sandrine Talano, Catherine Raffin, Branislav Musicki, Claire Bouix-Peter, Loic Tomas, Gilles Ouvry, Rémy Morgentin, Laurent F. Hennequin, Craig S. Harris
In our hands, efficient access to the 4-amino-3-carboxamide disubstituted pyridine-2(1H)-one kinase hinge-binder motif proved to be more challenging than anticipated requiring a significant investment in route scouting and optimization. This full paper focuses on the synthesis issues that we encountered during our route exploration and the original solutions we found that helped us to identify two
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Facile preparation and conversion of 4,4,4-trifluorobut-2-yn-1-ones to aromatic and heteroaromatic compounds Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-15 Takashi Yamazaki, Yoh Nakajima, Minato Iida, Tomoko Kawasaki-Takasuka
The concise preparation of 4,4,4-trifluorobut-2-yn-1-ones by the oxidation of the readily accessible corresponding propargylic alcohols as well as their utilization as Michael acceptors for the construction of aromatic and heteroaromatic compounds are reported.
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Tuning the solid-state emission of liquid crystalline nitro-cyanostilbene by halogen bonding Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-14 Subrata Nath, Alexander Kappelt, Matthias Spengler, Bibhisan Roy, Jens Voskuhl, Michael Giese
The first example of halogen-bonded fluorescent liquid crystals based on the interaction of iodofluorobenzene derivatives with nitro-cyanostilbenes is reported. The systematic variation of the fluorination degree and pattern indicates the relevance of the halogen bond strength for the induction of liquid crystalline properties. The modular self-assembly approach enables the efficient tuning of the
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Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-13 Michał M. Więcław, Bartłomiej Furman
Herein we present the direct asymmetric synthesis of tetrazole-functionalized 1-deoxynojirimycin derivatives from simple sugars via a Schwartz’s reagent-mediated reductive amide functionalization followed by a variant of the Ugi–azide multicomponent reaction. The anomeric configurations of two products were unambiguously confirmed by X-ray analysis. This work also describes examples of interesting
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Supramolecular polymerization of sulfated dendritic peptide amphiphiles into multivalent L-selectin binders Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-12 David Straßburger, Svenja Herziger, Katharina Huth, Moritz Urschbach, Rainer Haag, Pol Besenius
The synthesis of a sulfate-modified dendritic peptide amphiphile and its self-assembly into one-dimensional rod-like architectures in aqueous medium is reported. The influence of the ionic strength on the supramolecular polymerization was probed via circular dichroism spectroscopy and cryogenic transmission electron microscopy. Physiological salt concentrations efficiently screen the charges of the
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Supramolecular polymers with reversed viscosity/temperature profile for application in motor oils Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-12 Jan-Erik Ostwaldt, Christoph Hirschhäuser, Stefan K. Maier, Carsten Schmuck, Jochen Niemeyer
We report novel supramolecular polymers, which possess a reversed viscosity/temperature profile. To this end, we developed a series of ditopic monomers featuring two self-complementary binding sites, either the guanidiniocarbonyl pyrrole carboxylic acid (GCP) or the aminopyridine carbonyl pyrrole carboxylic acid (ACP). At low temperatures, small cyclic structures are formed. However, at elevated temperatures
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Synthesis of aryl 2-bromo-2-chloro-1,1-difluoroethyl ethers through the base-mediated reaction between phenols and halothane Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-11 Yukiko Karuo, Ayaka Kametani, Atsushi Tarui, Kazuyuki Sato, Kentaro Kawai, Masaaki Omote
An efficient and convenient method for the synthesis of structurally unique and highly functionalized aryl 2-bromo-2-chloro-1,1-difluoroethyl ethers has been developed. This approach exhibits a broad reaction scope, a simple operation and without the need of any expensive transition-metal catalyst, highly toxic or corrosive reagents. Notably, we demonstrate the potential utility of halothane for the
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Benzothiazolium salts as reagents for the deoxygenative perfluoroalkylthiolation of alcohols Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-08 Armin Ariamajd, Nils J. Gerwien, Benjamin Schwabe, Stefan Dix, Matthew N. Hopkinson
A series of 2-(perfluoroalkylthio)benzothiazolium (BT-SRF) salts have been synthesized that serve as convenient sources of hitherto underexplored perfluoroalkylthiolate anions. An investigation of their reactivity in a deoxygenative nucleophilic substitution reaction led to the development of an unprecedented process that provides pentafluoroethyl and heptafluoropropyl thioethers directly from readily
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Progress in the total synthesis of inthomycins Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-07 Bidyut Kumar Senapati
The inthomycin family of antibiotics, isolated from Streptomyces strains, are interesting molecules for synthesis due to their characteristic common oxazole polyene chiral allylic β-hydroxycarbonyl fragments and significant biological activities. The full structural motif of the inthomycins is found in several more complex natural products including the oxazolomycins, 16-methyloxazolomycin, curromycins
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Control over size, shape, and photonics of self-assembled organic nanocrystals Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-06 Chen Shahar, Yaron Tidhar, Yunmin Jung, Haim Weissman, Sidney R. Cohen, Ronit Bitton, Iddo Pinkas, Gilad Haran, Boris Rybtchinski
The facile fabrication of free-floating organic nanocrystals (ONCs) was achieved via the kinetically controlled self-assembly of simple perylene diimide building blocks in aqueous medium. The ONCs have a thin rectangular shape, with an aspect ratio that is controlled by the content of the organic cosolvent (THF). The nanocrystals were characterized in solution by cryogenic transmission electron microscopy
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Circularly polarized luminescent systems fabricated by Tröger's base derivatives through two different strategies Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-06 Cheng Qian, Yuan Chen, Qian Zhao, Ming Cheng, Chen Lin, Juli Jiang, Leyong Wang
The Tröger's base derivative rac-TBPP was synthesized and separated into two enantiomers R2N-TBPP and S2N-TBPP by chiral column chromatography. These compounds show a strong circularly polarized luminescence with glum values of +0.0021, and −0.0025, respectively. The second way to fabricate the rac-TBPP-based CPL-active material is to co-gel the fluorescent rac-TBPP with a chiral ᴅ-glutamic acid gelator
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The fluorescence of a mercury probe based on osthol Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-05 Guangyan Luo, Zhishu Zeng, Lin Zhang, Zhu Tao, Qianjun Zhang
The ability of osthol (OST) to recognize mercury ions in aqueous solution was studied using fluorescence, UV–vis spectrophotometry, mass spectrometry, and 1H NMR spectroscopy, and the recognition mechanism is discussed. The results showed that OST and Hg2+ can form a complex with a stoichiometric ratio of 1:1. The binding constant was 1.552 × 105 L∙mol−1, having a highly efficient and specific selectivity
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Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-05 Dimas J. P. Lima, Antonio E. G. Santana, Michael A. Birkett, Ricardo S. Porto
The 9-azabicyclo[3.3.1]nonane ring system is present in several insect- and plant-derived alkaloids. (−)-Adaline (1) and (+)-euphococcinine (2), found in secretions of Coccinelid beetles, and (+)-N-methyleuphococcinine (3), isolated from the Colorado blue spruce Picea pungens, are members of this alkaloid family. Their unique bicyclic system with a quaternary stereocenter, and the potent biological
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Molecular basis for protein–protein interactions Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-04 Brandon Charles Seychell, Tobias Beck
This minireview provides an overview on the current knowledge of protein–protein interactions, common characterisation methods to characterise them, and their role in protein complex formation with some examples. A deep understanding of protein–protein interactions and their molecular interactions is important for a number of applications, including drug design. Protein–protein interactions and their
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Synthesis, crystal structures and properties of carbazole-based [6]helicenes fused with an azine ring Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2021-01-04 Daria I. Tonkoglazova, Anna V. Gulevskaya, Konstantin A. Chistyakov, Olga I. Askalepova
Novel carbazole-based [6]helicenes fused with an azine ring (pyridine, pyrazine or quinoxaline) have been prepared through a five-step synthetic sequence in good overall yields. Commercially available 2,3-dihaloazines were used as starting materials. To discern the effect of merging an azine moiety within a helical skeleton, the X-ray structures, UV–vis absorption and fluorescence spectra of the helicenes
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Synthesis of tetrafluorinated piperidines from nitrones via a visible-light-promoted annelation reaction Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-29 Vyacheslav I. Supranovich, Igor A. Dmitriev, Alexander D. Dilman
A method for the one-step construction of 3,3,4,4-tetrafluorinated piperidines from nitrones and readily accessible tetrafluorinated iodobromobutane is described. The reaction requires an excess amount of ascorbic acid as the terminal reductant and is performed in the presence of an iridium photocatalyst activated by blue light. The annelation is a result of a radical addition at the nitrone, intramolecular
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An atom-economical addition of methyl azaarenes with aromatic aldehydes via benzylic C(sp3)–H bond functionalization under solvent- and catalyst-free conditions Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-23 Divya Rohini Yennamaneni, Vasu Amrutham, Krishna Sai Gajula, Rammurthy Banothu, Murali Boosa, Narender Nama
A convenient practical approach for the synthesis of 2-(pyridin-2-yl)ethanols by direct benzylic addition of azaarenes and aldehydes under catalyst- and solvent-free conditions is reported. This reaction is metal-free, green, and was carried out in a facile operative environment without using any hazardous transition metal catalysts or any other coupling reagents. Different aromatic aldehydes and azaarenes
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Silver-catalyzed synthesis of β-fluorovinylphosphonates by phosphonofluorination of aromatic alkynes Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-18 Yajing Zhang, Qingshan Tian, Guozhu Zhang, Dayong Zhang
A silver-catalyzed three-component reaction involving alkynes, Selectfluor®, and diethyl phosphite was employed for the one-pot formation of C(sp2)–F and C(sp2)–P bonds to provide an efficient access to β-fluorovinylphosphonates in a highly regio- and stereoselective manner under mild reaction conditions. This reaction is operationally simple and offers an excellent functional group tolerance as well
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Chemical constituents of Chaenomeles sinensis twigs and their biological activity Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-17 Joon Min Cha, Dong Hyun Kim, Lalita Subedi, Zahra Khan, Sang Un Choi, Sun Yeou Kim, Chung Sub Kim
A new megastigmane-type norsesquiterpenoid glycoside, chaemeloside (1), was isolated from the twigs of Chaenomeles sinensis together with 11 known phytochemicals through chromatographic methods. The chemical structure of the new isolate 1 was determined by conventional 1D and 2D NMR data analysis, ECD experiment, hydrolysis followed by a modified Mosher’s method, and LC–MS analysis. The characterized
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Amine–borane complex-initiated SF5Cl radical addition on alkenes and alkynes Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-16 Audrey Gilbert, Pauline Langowski, Marine Delgado, Laurent Chabaud, Mathieu Pucheault, Jean-François Paquin
The SF5Cl radical addition on unsaturated compounds was performed using an air-stable amine–borane complex as the radical initiator. This method showed to be complementary to the classic Et3B-mediated SF5Cl addition on alkenes and alkynes. A total of seven alkene and three alkyne derivatives were tested in the reaction, with yields ranging from 3% to 85%.
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Pentannulation of N-heterocycles by a tandem gold-catalyzed [3,3]-rearrangement/Nazarov reaction of propargyl ester derivatives: a computational study on the crucial role of the nitrogen atom Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-15 Giovanna Zanella, Martina Petrović, Dina Scarpi, Ernesto G. Occhiato, Enrique Gómez-Bengoa
The tandem gold(I)-catalyzed rearrangement/Nazarov reaction of enynyl acetates in which the double bond is embedded in a piperidine ring was computationally and experimentally studied. The theoretical calculations predict that the position of the propargylic acetate substituent has a great impact on the reactivity. In contrast to our previous successful cyclization of the 2-substituted substrates,
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Deoxyfluorination of acyl fluorides to trifluoromethyl compounds by FLUOLEAD®/Olah’s reagent under solvent-free conditions Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-14 Yumeng Liang, Akihito Taya, Zhengyu Zhao, Norimichi Saito, Norio Shibata
A new protocol enabling the formation of trifluoromethyl compounds from acyl fluorides has been developed. The combination of FLUOLEAD® and Olah’s reagent in solvent-free conditions at 70 °C initiated the significant deoxyfluorination of the acyl fluorides and resulted in the corresponding trifluoromethyl products with high yields (up to 99%). This strategy showed a great tolerance for various acyl
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Semiautomated glycoproteomics data analysis workflow for maximized glycopeptide identification and reliable quantification Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-11 Steffen Lippold, Arnoud H. de Ru, Jan Nouta, Peter A. van Veelen, Magnus Palmblad, Manfred Wuhrer, Noortje de Haan
Glycoproteomic data are often very complex, reflecting the high structural diversity of peptide and glycan portions. The use of glycopeptide-centered glycoproteomics by mass spectrometry is rapidly evolving in many research areas, leading to a demand in reliable data analysis tools. In recent years, several bioinformatic tools were developed to facilitate and improve both the identification and quantification
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Metal-free nucleophilic trifluoromethylselenolation via an iodide-mediated umpolung reactivity of trifluoromethylselenotoluenesulfonate Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-10 Kevin Grollier, Alexis Taponard, Arnaud De Zordo-Banliat, Emmanuel Magnier, Thierry Billard
We report herein a practical method to generate CF3Se− (and RFSe−) anions from shelf-stable reagents under iodide activation. Metal-free nucleophilic trifluoromethylselenolations have been then performed with this in situ-generated anion. Perfluoroalkylselenolations have also been described.
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All-carbon [3 + 2] cycloaddition in natural product synthesis Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-09 Zhuo Wang, Junyang Liu
Many natural products possess interesting medicinal properties that arise from their intriguing chemical structures. The highly-substituted carbocycle is one of the most common structural features in many structurally complicated natural products. However, the construction of highly-substituted, stereo-congested, five-membered carbocycles containing all-carbon quaternary center(s) is, at present, a
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Metal-free synthesis of biarenes via photoextrusion in di(tri)aryl phosphates Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-08 Hisham Qrareya, Lorenzo Meazza, Stefano Protti, Maurizio Fagnoni
A metal-free route for the synthesis of biarenes has been developed. The approach is based on the photoextrusion of a phosphate moiety occurring upon irradiation of biaryl- and triaryl phosphates. The reaction involves an exciplex as the intermediate and it is especially suitable for the preparation of electron-rich biarenes.
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Chiral anion recognition using calix[4]arene-based ureido receptors in a 1,3-alternate conformation Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-07 Tereza Horáčková, Jan Budka, Vaclav Eigner, Wen-Sheng Chung, Petra Cuřínová, Pavel Lhoták
The introduction of chiral alkyl substituents into the lower rim of calix[4]arene immobilised in the 1,3-alternate conformation led to a system possessing a preorganised ureido cavity hemmed with chiral alkyl units in the near proximity. As shown by the 1H NMR titration experiments, these compounds can be used as receptors for chiral anions in DMSO-d6. The chiral recognition ability can be further
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Secondary metabolites of Bacillus subtilis impact the assembly of soil-derived semisynthetic bacterial communities Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-04 Heiko T. Kiesewalter, Carlos N. Lozano-Andrade, Mikael L. Strube, Ákos T. Kovács
Secondary metabolites provide Bacillus subtilis with increased competitiveness towards other microorganisms. In particular, nonribosomal peptides (NRPs) have an enormous antimicrobial potential by causing cell lysis, perforation of fungal membranes, enzyme inhibition, or disruption of bacterial protein synthesis. This knowledge was primarily acquired in vitro when B. subtilis was competing with other
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Selected peptide-based fluorescent probes for biological applications Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-03 Debabrata Maity
To understand the molecular interactions, present in living organisms and their environments, chemists are trying to create novel chemical tools. In this regard, peptide-based fluorescence techniques have attracted immense interest. Synthetic peptide-based fluorescent probes are advantageous over protein-based sensors, since they are synthetically accessible, more stable, and can be easily modified
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Construction of pillar[4]arene[1]quinone–1,10-dibromodecane pseudorotaxanes in solution and in the solid state Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-02 Xinru Sheng, Errui Li, Feihe Huang
We report novel pseudorotaxanes based on the complexation between pillar[4]arene[1]quinone and 1,10-dibromodecane. The complexation is found to have a 1:1 host–guest complexation stoichiometry in chloroform but a 2:1 host–guest complexation stoichiometry in the solid state. From single crystal X-ray diffraction, the linear guest molecules thread into cyclic pillar[4]arene[1]quinone host molecules in
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Naphthalonitriles featuring efficient emission in solution and in the solid state Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-02 Sidharth Thulaseedharan Nair Sailaja, Iván Maisuls, Jutta Kösters, Alexander Hepp, Andreas Faust, Jens Voskuhl, Cristian A. Strassert
In this work, a series of γ-substituted diphenylnaphthalonitriles were synthesized and characterized. They show efficient emission in solution and in the aggregated state and their environment responsiveness is based on having variable substituents at the para-position of the two phenyl moieties. The excited state properties were fully investigated in tetrahydrofuran (THF) solutions and in THF/H2O
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Regioselective synthesis of heterocyclic N-sulfonyl amidines from heteroaromatic thioamides and sulfonyl azides Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-01 Vladimir Ilkin, Vera Berseneva, Tetyana Beryozkina, Tatiana Glukhareva, Lidia Dianova, Wim Dehaen, Eugenia Seliverstova, Vasiliy Bakulev
N-Sulfonyl amidines bearing 1,2,3-triazole, isoxazole, thiazole and pyridine substituents were successfully prepared for the first time by reactions of primary, secondary and tertiary heterocyclic thioamides with alkyl- and arylsulfonyl azides. For each type of thioamides a reliable procedure to prepare N-sulfonyl amidines in good yields was found. Reactions of 1-aryl-1,2,3-triazole-4-carbothioamides
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Controlled decomposition of SF6 by electrochemical reduction Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-12-01 Sébastien Bouvet, Bruce Pégot, Stéphane Sengmany, Erwan Le Gall, Eric Léonel, Anne-Marie Goncalves, Emmanuel Magnier
The electroreduction of SF6 is shown at ambient temperature in acetonitrile using an array of platinum microelectrodes to improve the electrical detection. Its half reduction potential occurs at −2.17 V vs Fc+/Fc. The exact number of electrons for the full consumption of sulfur hexafluoride was determined and this gas further quantitatively transformed into environmentally benign fluoride anion and
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Three-component reactions of aromatic amines, 1,3-dicarbonyl compounds, and α-bromoacetaldehyde acetal to access N-(hetero)aryl-4,5-unsubstituted pyrroles Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-30 Wenbo Huang, Kaimei Wang, Ping Liu, Minghao Li, Shaoyong Ke, Yanlong Gu
N-(Hetero)aryl-4,5-unsubstituted pyrroles were synthesized from (hetero)arylamines, 1,3-dicarbonyl compounds, and α-bromoacetaldehyde acetal by using aluminum(III) chloride as a Lewis acid catalyst through [1 + 2 + 2] annulation. This new versatile methodology provides a wide scope for the synthesis of different functional N-(hetero)aryl-4,5-unsubstituted pyrrole scaffolds, which can be further derived
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Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-30 Emese Gal, Luiza Gaina, Hermina Petkes, Alexandra Pop, Castelia Cristea, Gabriel Barta, Dan Cristian Vodnar, Luminiţa Silaghi-Dumitrescu
This work describes an efficient, simple, and ecofriendly sonochemical procedure for the preparation of new α-(arylamino)acetonitrile derivatives C-substituted with phenothiazine or ferrocene units. The synthetic protocol is based on the Strecker reaction of a (hetero)aryl aldimine substrate with trimethylsilyl cyanide (TMSCN) in poly(ethylene glycol) (PEG) solution. The advantages of the sonochemical
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UV resonance Raman spectroscopy of the supramolecular ligand guanidiniocarbonyl indole (GCI) with 244 nm laser excitation Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-27 Tim Holtum, Vikas Kumar, Daniel Sebena, Jens Voskuhl, Sebastian Schlücker
Ultraviolet resonance Raman (UVRR) spectroscopy is a powerful vibrational spectroscopic technique for the label-free monitoring of molecular recognition of peptides or proteins with supramolecular ligands such as guanidiniocarbonyl pyrroles (GCPs). The use of UV laser excitation enables Raman binding studies of this class of supramolecular ligands at submillimolar concentrations in aqueous solution
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A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-26 Bingbing Lai, Meng Ye, Ping Liu, Minghao Li, Rongxian Bai, Yanlong Gu
A waste biomass, sodium lignosulfonate, was treated with sodium 2-formylbenzenesulfonate, and the phenylaldehyde condensation product was then used as a robust supporting material to immobilize a copper species. The so-obtained catalyst was characterized by many physicochemical methods including FTIR, EA, FSEM, FTEM, XPS, and TG. This catalyst exhibited excellent catalytic activity in the synthesis
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Synthesis of imidazo[1,5-a]pyridines via cyclocondensation of 2-(aminomethyl)pyridines with electrophilically activated nitroalkanes Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-26 Dmitrii A. Aksenov, Nikolai A. Arutiunov, Vladimir V. Maliuga, Alexander V. Aksenov, Michael Rubin
Imidazo[1,5-a]pyridines were efficiently prepared via the cyclization of 2-picolylamines with nitroalkanes electrophilically activated in the presence of phosphorous acid in polyphosphoric acid (PPA) medium.
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Incorporation of a metal-mediated base pair into an ATP aptamer – using silver(I) ions to modulate aptamer function Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-25 Marius H. Heddinga, Jens Müller
For the first time, a metal-mediated base pair has been used to modulate the affinity of an aptamer towards its target. In particular, two artificial imidazole 2’-deoxyribonucleosides (Im) were incorporated into various positions of an established ATP-binding aptamer (ATP, adenosine triphosphate), resulting in the formation of three aptamer derivatives bearing Im:Im mispairs with a reduced ATP affinity
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Fluorine effect in nucleophilic fluorination at C4 of 1,6-anhydro-2,3-dideoxy-2,3-difluoro-β-D-hexopyranose Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-25 Danny Lainé, Vincent Denavit, Olivier Lessard, Laurie Carrier, Charles-Émile Fecteau, Paul A. Johnson, Denis Giguère
In this work, we have developed a simple synthetic approach using Et3N·3HF as an alternative to the DAST reagent. We controlled the stereochemistry of the nucleophilic fluorination at C4 of 1,6-anhydro-2,3-dideoxy-2,3-difluoro-4-O-triflate-β-ᴅ-talopyranose using Et3N·3HF or in situ generated Et3N·1HF. The influence of the fluorine atom at C2 on reactivity at C4 could contribute to a new fluorine effect
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One-pot multicomponent green Hantzsch synthesis of 1,2-dihydropyridine derivatives with antiproliferative activity Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-24 Giovanna Bosica, Kaylie Demanuele, José M. Padrón, Adrián Puerta
A rapid route for obtaining unsymmetrical 1,2-dihydropyridines (1,2-DHPs) as opposed to 1,4-dihydropyridines (1,4-DHPs) has been achieved via a one-pot multicomponent Hantzsch reaction. A benign protocol has been developed for the preparation of various 1,2-dihydropyridine derivatives using heterogenized phosphotungstic acid on alumina support (40 wt %). High yields of over 75% have been accomplished
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Changed reactivity of secondary hydroxy groups in C8-modified adenosine – lessons learned from silylation Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-23 Jennifer Frommer, Sabine Müller
Synthesis of site-specifically modified oligonucleotides has become a major tool for RNA structure and function studies. Reporter groups or specific functional entities are required to be attached at a pre-defined site of the oligomer. An attractive strategy is the incorporation of suitably functionalized building blocks that allow post-synthetic conjugation of the desired moiety. A C8-alkynyl-modified
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Using multiple self-sorting for switching functions in discrete multicomponent systems Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-20 Amit Ghosh, Michael Schmittel
Over years self-sorting has developed into a powerful tool in supramolecular chemistry, for instance, to promote the error-free formation of intricate multicomponent assemblies. However, in order to use the enormous potential of self-sorting for sophisticated information processing more recent developments have focused on the reversible reconfiguration of multicomponent systems driven by multiple self-sorting
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On the mass spectrometric fragmentations of the bacterial sesterterpenes sestermobaraenes A–C Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-19 Anwei Hou, Jeroen S. Dickschat
A 13C-labelling was introduced into each individual carbon of the recently discovered sestermobaraenes by the enzymatic conversion of the correspondingly 13C-labelled isoprenyl diphosphate precursors with the sestermobaraene synthase from Streptomyces mobaraensis. The main compounds sestermobaraenes A, B, and C were analysed by gas chromatography–mass spectrometry (GC–MS), allowing for a deep mechanistic
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Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-19 David Liese, Hans Henning Wenk, Xin Lu, Jochen Kleinen, Gebhard Haberhauer
We report new dirhamnolipid ester forming reverse wormlike micelles in nonpolar solvents without the addition of any primer. Therefore, these compounds represent a rare case of a binary system showing this gel-like behavior. In this study, the influence of the concentration of the rhamnolipid ester and the ester alkyl chain length on the rheological properties of the reverse wormlike micelles in toluene
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Synthesis and investigation of quadruplex-DNA-binding, 9-O-substituted berberine derivatives Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-18 Jonas Becher, Daria V. Berdnikova, Heiko Ihmels, Christopher Stremmel
A small series of five novel berberine derivatives was synthesized by the Cu-catalyzed click reaction of 9-propargyladenine with 9-O-(azidoalkyl)berberine derivatives. The association of the resulting berberine–adenine conjugates with representative quadruplex-forming oligonucleotides 22AG dA(G3TTA)3G3 and a2 d(ACAG4TGTG4)2 was examined with photometric and fluorimetric titrations, thermal DNA denaturation
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Easy access to a carbohydrate-based template for stimuli-responsive surfactants Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-17 Thomas Holmstrøm, Daniel Raydan, Christian Marcus Pedersen
In this paper we describe the synthesis of a new carbohydrate-based building block functionalized with azido or amino groups on the 2 and 4 positions. The building block can be synthesized in anomerically pure form in only five scalable steps starting from commercially available levoglucosan. It was shown that the building block could undergo alkylations under strongly basic conditions. The building
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3-Acetoxy-fatty acid isoprenyl esters from androconia of the ithomiine butterfly Ithomia salapia Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-16 Florian Mann, Daiane Szczerbowski, Lisa de Silva, Melanie McClure, Marianne Elias, Stefan Schulz
Male ithomiine butterflies (Nymphalidae: Danainae) have hairpencils on the forewings (i.e., androconia) that disseminate semiochemicals during courtship. While most ithomiines are known to contain derivatives of pyrrolizidine alkaloids, dihydropyrrolizines, or γ-lactones in these androconia, here we report on a new class of fatty acid esters identified in two subspecies, Ithomia salapia aquinia and
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Ring-closing metathesis of prochiral oxaenediynes to racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-13 Viola Kolaříková, Markéta Rybáčková, Martin Svoboda, Jaroslav Kvíčala
The prochiral 4-(allyloxy)hepta-1,6-diynes, optionally modified in the positions 1 and 7 with an alkyl or ester group, undergo a chemoselective ring-closing enyne metathesis yielding racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans. Among the catalysts tested, Grubbs 1st generation precatalyst in the presence of ethene (Mori conditions) gave superior results compared to the more stable Grubbs or Hoveyda–Grubbs
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Bifurcated synthesis of methylene-lactone- and methylene-lactam-fused spirolactams via electrophilic amide allylation of γ-phenylthio-functionalized γ-lactams Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-13 Tetsuya Sengoku, Koki Makino, Ayumi Iijima, Toshiyasu Inuzuka, Hidemi Yoda
New synthetic methods for spirolactams bearing an α-methylene-γ-butyrolactone or its analogous methylene-lactam have been developed. The allylation of γ-phenylthio-functionalized γ-lactams with 2-(acetoxy)methyl acrylamides was accomplished by using 2.5 equivalents of NaH to give the corresponding adducts in excellent yields. The remaining phenylthio group was substituted with a hydroxy group by treatment
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Encrypting messages with artificial bacterial receptors Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-12 Pragati Kishore Prasad, Naama Lahav-Mankovski, Leila Motiei, David Margulies
A method for encrypting messages using engineered bacteria and different fluorescently labeled synthetic receptors is described. We show that the binding of DNA-based artificial receptors to E. coli expressing His-tagged outer membrane protein C (His-OmpC) induces a Förster resonance energy transfer (FRET) between the dyes, which results in the generation of a unique fluorescence fingerprint. Because
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Selective recognition of ATP by multivalent nano-assemblies of bisimidazolium amphiphiles through “turn-on” fluorescence response Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-10 Rakesh Biswas, Surya Ghosh, Shubhra Kanti Bhaumik, Supratim Banerjee
Bisimidazolium receptors, tagged with chromophoric pyrene at one end and linked to an n-alkyl chain at the other, underwent self-assembly in aqueous media depending on the length of the alkyl segment. The amphiphilic derivatives having n-decyl or longer chains, formed nano-assemblies with cyanic–green emission resulting from the stacked pyrene chromophores in the aggregates. The presence of positive
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Synthesis of purines and adenines containing the hexafluoroisopropyl group Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-11 Viacheslav Petrov, Rebecca J. Dooley, Alexander A. Marchione, Elizabeth L. Diaz, Brittany S. Clem, William Marshall
Several new derivatives of adenine, purine, and theophylline containing the (CF3)2CH group connected to a nitrogen atom of the imidazole ring were prepared by the reaction of 2,2,4,4-tetrakis(trifluoromethyl)-1,3-dithietane (1) with the corresponding substrates, resulting in the selective alkylation of one of the nitrogen atoms of the imidazole ring. The reaction proceeds under mild conditions in a
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Nocarimidazoles C and D, antimicrobial alkanoylimidazoles from a coral-derived actinomycete Kocuria sp.: application of 1JC,H coupling constants for the unequivocal determination of substituted imidazoles and stereochemical diversity of anteisoalkyl chains in microbial metabolites Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-05 Md. Rokon Ul Karim, Enjuro Harunari, Amit Raj Sharma, Naoya Oku, Kazuaki Akasaka, Daisuke Urabe, Mada Triandala Sibero, Yasuhiro Igarashi
Chemical investigation of secondary metabolites from a marine-derived actinomycete strain of the genus Kocuria, isolated from a stony coral Mycedium sp., led to the identification of two new alkanoylimidazoles, nocarimidazoles C (1) and D (2) as well as three known congeners, nocarimidazoles A (3) and B (4) and bulbimidazole A (5). Structure analysis of 1 and 2 by NMR and MS revealed that both are
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Enzyme-instructed morphological transition of the supramolecular assemblies of branched peptides Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-04 Dongsik Yang, Hongjian He, Bing Xu
Here, we report the use of an enzymatic reaction to cleave the branch off branched peptides for inducing the morphological transition of the assemblies of the peptides. The attachment of DEDDDLLI sequences to the ε-amine of the lysine residue of a tetrapeptide produces branched peptides that form micelles. Upon the proteolytic cleavage of the branch, catalyzed by proteinase K, the micelles turn into
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A heterobimetallic tetrahedron from a linear platinum(II)-bis(acetylide) metalloligand Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-03 Matthias Hardy, Marianne Engeser, Arne Lützen
Employing 4-ethynylaniline as a simple organic ligand we were able to prepare the stable trans-bis(acetylide)platinum(II) complex [Pt(L1)2(PBu3)2] as a linear metalloligand. The reaction of this metalloligand with iron(II) cations and pyridine-2-carbaldehyde according to the subcomponent self-assembly approach yielded decanuclear heterobimetallic tetrahedron [Fe4Pt6(L2)12](OTf)8. Thus, combination
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Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes Beilstein. J. Org. Chem. (IF 2.622) Pub Date : 2020-11-02 Lena Reinke, Julia Bartl, Marcus Koch, Stefan Kubik
Gold nanoparticles covered with a mixture of ligands of which one type contains solubilizing triethylene glycol residues and the other peripheral zinc(II)–dipicolylamine (DPA) complexes allowed the optical detection of hydrogenphosphate, diphosphate, and triphosphate anions in water/methanol 1:2 (v/v). These anions caused the bright red solutions of the nanoparticles to change their color because of
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