Synthesis and investigation of quadruplex-DNA-binding, 9-O-substituted berberine derivatives

• Jonas Becher,
• Daria V. Berdnikova,
• Heiko Ihmels and
• Christopher Stremmel

Beilstein J. Org. Chem. 2020, 16, 2795–2806, doi:10.3762/bjoc.16.230

• moderate yields (16–38%), mainly because of severe difficulties to completely remove the copper ions that apparently bind tightly to the compounds. The new compounds 4a–e were identified and fully characterized with NMR spectroscopy (1H, 13C, COSY, HSQC, HMBC), mass spectrometry, and elemental analysis

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

• Phil M. Pithan,
• Sören Steup and
• Heiko Ihmels

Beilstein J. Org. Chem. 2020, 16, 904–916, doi:10.3762/bjoc.16.82

• conditions, indicating an electron transfer from a reaction intermediate to the copper ions. In addition, we tested whether 4a may also be formed upon the addition of the previously not employed Fe3+ ion as this also acts as a strong electron acceptor (Figure 6B). Indeed, the addition of Fe3+ to 3a resulted

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• Pezhman Shiri Jasem Aboonajmi Department of Chemistry, Shiraz University, Shiraz, Iran 10.3762/bjoc.16.52 Abstract In recent years, many inorganic silica/carbon-based and magnetic materials have been selected to arrest copper ions through a widespread range of anchoring and embedding

• graphene oxide (rGO) with copper and palladium species (Scheme 15) [77]. In this study, graphite oxide (GO) was generated according to the modified Hummer’s method. Copper(II) was anchored on GO via ultrasonication. In the next step, copper ions were reduced by adding NaBH4. The mixture was then heated at

• materials. Due to the incorporation of 137 and 132, the capacity of the obtained magnetic nanocomposite 135 to complex Cu(II) ions was high. As such, copper ions were loaded into the magnetic nanocomposite, yielding 136. The most important benefit of the magnetic nanoparticles being situated within the

Exploring mechanochemistry to turn organic bio-relevant molecules into metal-organic frameworks: a short review

• Vânia André,
• Sílvia Quaresma,
• João Luís Ferreira da Silva and
• M. Teresa Duarte

Beilstein J. Org. Chem. 2017, 13, 2416–2427, doi:10.3762/bjoc.13.239

• achieve a controlled release of biologically active copper ions and it has shown to be an effective antifungal agent against representative yeast and mold [135]. Friščić et al. also reported the synthesis of coordination polymers and BioMOFs using LAG by grinding together zinc oxide and fumaric acid. In

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• lower content of copper compounds in the reaction mixture. This strongly indicates that during mechanochemical reactions with milling balls containing copper(0), the catalytic process is mostly happening on the surface of milling balls, and diffusion of copper ions to reaction mixture is minute. This

• asterisks are characteristic for copper(II) acetate monohydrate [53]. These lines reveal the presence of two strongly antiferromagnetically coupled copper ions with spin S = 1/2. In the spectrum of the product obtained by method 2a, an additional strong signal is detected (peaks at g = 2.02 and g = 2.3

• transformation of reactants to products. Thus, we propose that the catalytic reaction for the method 2c is most likely occurring on the surface of brass milling balls, with minute diffusion of the copper ions to the reaction mixture. During the milling reactions, copper(0) and copper(I) catalysts do not oxidize

A postsynthetically 2’-“clickable” uridine with arabino configuration and its application for fluorescent labeling and imaging of DNA

• Heidi-Kristin Walter,
• Bettina Olshausen,
• Ute Schepers and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2017, 13, 127–137, doi:10.3762/bjoc.13.16

• modified oligonucleotides were purified by ethanol precipitation in the presence of EDTA to remove copper ions and subsequently by semi-preparative HPLC. Finally, the modified oligonucleotides were identified by MALDI–TOF mass spectrometry (see Supporting Information File 1) and annealed with the

Elongated and substituted triazine-based tricarboxylic acid linkers for MOFs

• Arne Klinkebiel,
• Ole Beyer,
• Barbara Malawko and
• Ulrich Lüning

Beilstein J. Org. Chem. 2016, 12, 2267–2273, doi:10.3762/bjoc.12.219

• -benzenetricarboxylic acid (BTC, forming HKUST-1 [6] in the presence of copper ions), an obvious elongated building block is BTB (1,3,5-benzenetribenzoate, Figure 1, left) forming for instance MOF-14 [7]. But this type of elongation has a drawback: the direct vicinity of the aryl groups does not allow planarity due to

Amidofluorene-appended lower rim 1,3-diconjugate of calix[4]arene: synthesis, characterization and highly selective sensor for Cu²⁺

• Rahman Hosseinzadeh,
• Mohammad Nemati,
• Reza Zadmard and
• Maryam Mohadjerani

Beilstein J. Org. Chem. 2016, 12, 1749–1757, doi:10.3762/bjoc.12.163

• of 9.6 × 10−8 M. Keywords: calix[4]arene; chemosensor; copper ions; fluorene; fluorescence; Introduction Owing to the substantial role of fluorescent chemosensors in biological, environmental, and chemical processes, their design and synthesis, especially for detection of metal ions has attracted

• different binding centers such as nitrogen, oxygen and sulfur sites for recognition of metal ions can be readily synthesized [14][16][17]. A number of calix[4]arene-based fluorescence sensors for copper ions have been reported in the literature [18][19][20][21][22][23][24][25][26][27], including calix[4

• during the complex formation. The fact that receptor L shows a sensitive recognition affinity to copper ions and a much more obvious shift of 1H NMR peaks in the presence of Cu2+ is actually not surprising because of a relatively rigid binding pocket of receptor L providing four sites of NH and OH which

Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA

• Svetlana V. Vasilyeva,
• Vyacheslav V. Filichev and
• Alexandre S. Boutorine

Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128

• transformations. So, this reaction is suitable for the synthesis of different biologically important conjugates including polyamide-TFO conjugates and fluorescent probes based on these components. Several methods avoiding the presence of cytotoxic copper ions have been also described [27][28][29]. Baskin et al

• was used for their final purification. DNA-templated synthesis of TFO-MGB conjugates It has been shown that the presence of copper ions does not prevent duplex and triplex formation and the DNA-directed cycloaddition reaction proceed smoothly on these templates [38]. In 2003, the team of P. Dervan

• necessary reagents were added. Standard 20% denaturing PAGE analysis (Figure 15) demonstrated that the conjugation occurs only in the presence of copper ions, however, with quite low yields, possibly due to low concentration of components. The effect of the DNA template on the formation of conjugates was

Bi- and trinuclear copper(I) complexes of 1,2,3-triazole-tethered NHC ligands: synthesis, structure, and catalytic properties

• Shaojin Gu,
• Jiehao Du,
• Jingjing Huang,
• Huan Xia,
• Ling Yang,
• Weilin Xu and
• Chunxin Lu

Beilstein J. Org. Chem. 2016, 12, 863–873, doi:10.3762/bjoc.12.85

• two L2 ligands. The two ligands are arranged in head-to-tail manner. The copper ions are each tri-coordinated by one carbene carbon atom, one nitrogen from pyrimidine, and one nitrogen atom of the triazole rings from two different L2 ligands. The Cu–carbene bond distances are 1.896(6) and 1.899(5) Å

Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds

• Sophie Letort,
• Sébastien Balieu,
• William Erb,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2016, 12, 204–228, doi:10.3762/bjoc.12.23

• efficiency of the CD derivative, the monofunctionalization of the C-3 alcohols was carried out [86]. The temporary complexation of specific β-CD secondary hydroxy functions allows the monofunctionalization of the C-3 position through the formation of a copper(II)–β-CD complex. A diagonal link between copper

• ions and C-2 and C-3 oxygen atoms of adjacent glucopyranose units might distort the CD cavity, making the hydroxy groups on position 3 more accessible. Moreover, as this complex is formed in aqueous sodium hydroxide, the hydroxy groups could be deprotonated in situ to perform the subsequent

Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II)-ethylenediamine precatalyst

• Redouane Beniazza,
• Natalia Bayo,
• Florian Molton,
• Carole Duboc,
• Stéphane Massip,
• Nathan McClenaghan,
• Dominique Lastécouères and
• Jean-Marc Vincent

Beilstein J. Org. Chem. 2015, 11, 1950–1959, doi:10.3762/bjoc.11.211

• molecules being most probably bound to the copper ions in aqueous solution, while in THF, the carboxylates interact more tightly with the copper ions. This is in agreement with the 1H NMR spectra of 1, which showed well resolved peaks for the benzophenone protons in D2O, while in THF-d8 broad resonances

Quarternization of 3-azido-1-propyne oligomers obtained by copper(I)-catalyzed azide–alkyne cycloaddition polymerization

• Shun Nakano,
• Akihito Hashidzume and
• Takahiro Sato

Beilstein J. Org. Chem. 2015, 11, 1037–1042, doi:10.3762/bjoc.11.116

• monomer precursor, and obtained its oligomer, whose backbone is composed of 1,2,3-triazole and methylene moieties (Scheme 1a) [37]. The oligomer obtained was crystalline and adsorbed strongly copper ions. Since the oligomer was soluble only in strong acids and insoluble in water and organic solvents, it

Mechanical stability of bivalent transition metal complexes analyzed by single-molecule force spectroscopy

• Manuel Gensler,
• Christian Eidamshaus,
• Maurice Taszarek,
• Hans-Ulrich Reissig and
• Jürgen P. Rabe

Beilstein J. Org. Chem. 2015, 11, 817–827, doi:10.3762/bjoc.11.91

• interactions with the Cu2+ ligand. In 3 mM CuSO4, ligand 2c showed the same behavior as the monovalent system 1, but a different in 30 mM CuSO4. The latter was used for the analysis presented here. Expected coordination complexes of monovalent and bivalent structures (1 and 2a–c, respectively) with copper ions

Self-assembly of heteroleptic dinuclear metallosupramolecular kites from multivalent ligands via social self-sorting

• Christian Benkhäuser and
• Arne Lützen

Beilstein J. Org. Chem. 2015, 11, 693–700, doi:10.3762/bjoc.11.79

• . Connecting two of these ligands with a concave or V-shaped building block with a rather large bent angle should then prevent the formation of discrete oligonuclear cyclic assemblies due to the fact that the chelating units cannot be arranged in the favorable tetrahedral coordination of the copper ions

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

• Véronique Nardello-Rataj and
• Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

• authors mentioned than the loaded copper ions interact with bacterial cell membranes which induced structural change and leading to cell death. The proposed system can be useful to water purification systems and filtration membrane. Intrinsic biocidal activity of CDs and synergism effect As mentioned

Host–guest-driven color change in water: influence of cyclodextrin on the structure of a copper complex of poly((4-hydroxy-3-(pyridin-3-yldiazenyl)phenethyl)methacrylamide-co-dimethylacrylamide)

• Nils Retzmann,
• Gero Maatz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2480–2483, doi:10.3762/bjoc.10.259

• of CD–dye hydrogels by addition of metal ions, as well as the sensing of copper ions using cyclodextrin–dye rotaxane [10][11]. Herewith we thus wish to describe our recent results about the synthesis of a water-soluble polymer bearing a novel azo dye and the presumed formation of complexes with Cu

• Figure 1. The addition of CuSO4 to polymer 7 in a water/methanol mixture caused a color change from orange to red, which could be reversed by subsequent addition of γ-CD (Figure 1). Thus, we can anticipate a donor–acceptor-type bonding of the electron-rich azo dye with copper ions, that can be displaced

• addition. Assuming an intermolecular aggregating effect due to ionic interactions between the covalently attached azo dyes in 7 and Cu ions in solution, dynamic light scattering (DLS) experiments in a water/methanol solution were carried out (Figure 3). It was found that, by introducing copper ions to 7

Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

• Regina Berg and
• Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

• Huisgen’s azide–alkyne cycloaddition (CuAAC reaction). In fact, the catalytic effect of copper ions had first been mentioned by L’Abbé in 1984 [7], but had henceforth been overlooked until Meldal presented a copper(I)-catalyzed solid-phase synthesis of 1,2,3-triazoles. In this procedure, the terminal alkyne

• proteins from oxidative coupling [45][46]. However, the latter phosphine reagent should only be used in low quantities, as its binding to copper ions has an inhibitory effect. Another disadvantage of using TCEP is the consumption of the azide substrates in Staudinger reactions [56][57][58] with the

• tris(hydroxypropyltriazolylmethyl)amine (THPTA, Figure 1) was present [64]. In bioorganic chemistry, research efforts have focused on developing ligands that can prevent the copper ions from causing biological damage [68][69][70]. Apart from TBTA that had been shown to increase the biocompatibility of

Copper(II)-salt-promoted oxidative ring-opening reactions of bicyclic cyclopropanol derivatives via radical pathways

• Eietsu Hasegawa,
• Minami Tateyama,
• Ryosuke Nagumo,
• Eiji Tayama and
• Hajime Iwamoto

Beilstein J. Org. Chem. 2013, 9, 1397–1406, doi:10.3762/bjoc.9.156

• derivatives were investigated. The regioselectivities of these processes were found to be influenced by the structure of cyclopropanols as well as the counter anion of the copper(II) salts. A mechanism involving rearrangement reactions of radical intermediates and their competitive trapping by copper ions is

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• yields. Enzyme laccase Enzyme laccase is a family of “blue-copper” oxidase proteins, containing four copper ions in the active site, which cooperates in the degradation of the biopolymer lignin in woody tissues. With respect to other powerful oxidant enzymes, laccase has a lower redox potential. For this

Metal-mediated aminocatalysis provides mild conditions: Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions

• Matthias Leven,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2013, 9, 155–165, doi:10.3762/bjoc.9.18

• direct aldol reaction, which is mediated by copper ions and amino acid derivatives [14] or enamine nucleophilic addition to palladium π-allyl electrophiles [15][16][17]. We report the development of new catalysts based on chiral 1,2-diamines and present their application in the asymmetric addition of 4

Peptoids and polyamines going sweet: Modular synthesis of glycosylated peptoids and polyamines using click chemistry

• Daniel Fürniss,
• Timo Mack,
• Frank Hahn,
• Sidonie B. L. Vollrath,
• Katarzyna Koroniak,
• Ute Schepers and
• Stefan Bräse

Beilstein J. Org. Chem. 2013, 9, 56–63, doi:10.3762/bjoc.9.7

• copper ions. In some cases, changing the base from DIPEA to DBU was beneficial (Scheme 2). After these encouraging results, we turned our attention to peptoids. For the glycosylation of peptoids, we envisaged the generation of a fully glycosylated peptoid in order to investigate the compatibility of

Anthracene coupled adenine for the selective sensing of copper ions

• Kumaresh Ghosh and
• Tanushree Sen

Beilstein J. Org. Chem. 2010, 6, No. 44, doi:10.3762/bjoc.6.44

• ions, especially Cu2+ ion. Conclusion In conclusion, the above studies have led to the development of adenine–linked fluorescent probes 1 and 2, which selectively respond to copper ions. The chemosensors display fluorescent changes upon complexation with Cu2+ ions. The emission of 1 is greatly

Bioorthogonal metabolic glycoengineering of human larynx carcinoma (HEp-2) cells targeting sialic acid

• Arne Homann,
• Riaz-ul Qamar,
• Sevnur Serim,
• Petra Dersch and
• Jürgen Seibel

Beilstein J. Org. Chem. 2010, 6, No. 24, doi:10.3762/bjoc.6.24

• dimethylsulfoxide (DMSO) (Scheme 5). After one hour, the cells were analyzed by microscopy (phase contrast) at the appropriate wavelength for fluorescence imaging. Although the incubation of HEp-2 in DMSO and in the presence of copper ions is cytotoxic, the fluorescence in the labelled glycocalyx was clearly