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Search for "circular dichroism" in Full Text gives 130 result(s) in Beilstein Journal of Organic Chemistry.

Sesquiterpenes from the soil-derived fungus Trichoderma citrinoviride PSU-SPSF346

  • Wiriya Yaosanit,
  • Vatcharin Rukachaisirikul,
  • Souwalak Phongpaichit,
  • Sita Preedanon and
  • Jariya Sakayaroj

Beilstein J. Org. Chem. 2022, 18, 479–485, doi:10.3762/bjoc.18.50

Graphical Abstract
  • electronic circular dichroism (ECD) data with those of compound 3, whereas that of compound 2 was proposed based on biosynthetic considerations. The structures of the known compounds were further confirmed by comparison of their 1H and 13C NMR spectroscopic data, specific rotations, and ECD data with those
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Published 29 Apr 2022

Synthesis and bioactivity of pyrrole-conjugated phosphopeptides

  • Qiuxin Zhang,
  • Weiyi Tan and
  • Bing Xu

Beilstein J. Org. Chem. 2022, 18, 159–166, doi:10.3762/bjoc.18.17

Graphical Abstract
  • dephosphorylation of 6b (Supporting Information File 1, Figure S33) after the addition of ALP. In addition to the TEM images, we used circular dichroism (CD) to reveal the secondary structures of the assemblies before and after enzymatic action. The spectra show a significant change in the signal upon ALP treatment
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Published 31 Jan 2022

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

  • Hendrik Gruß,
  • Rebecca C. Feiner,
  • Ridhiwan Mseya,
  • David C. Schröder,
  • Michał Jewgiński,
  • Kristian M. Müller,
  • Rafał Latajka,
  • Antoine Marion and
  • Norbert Sewald

Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1

Graphical Abstract
  • moreover, explains the increased binding affinity to β-catenin as P5 is more likely to be found in an active conformation. Analysis of the secondary structure by circular dichroism: CD spectra of both isomers of stapled peptide P5 (P5.1 and P5.2) and linear references (aAxWt, P6) (c = 100 µM) at 20 °C in
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Published 03 Jan 2022

Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

  • Zhiwei Zhang,
  • Tao Zhou,
  • Taehui Yang,
  • Keisuke Fukaya,
  • Enjuro Harunari,
  • Shun Saito,
  • Katsuhisa Yamada,
  • Chiaki Imada,
  • Daisuke Urabe and
  • Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141

Graphical Abstract
  • (Table S1, Supporting Information File 1) and 3JHH coupling constants [15]. The absolute configuration of 1 was deduced to be the same as 4 in consideration of the overall similarity of the electronic circular dichroism (ECD) spectra of 1 and 4 (Figure 4). This proposition was evidenced by the density
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Published 27 Aug 2021

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

  • Nikita Brodyagin,
  • Martins Katkevics,
  • Venubabu Kotikam,
  • Christopher A. Ryan and
  • Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

Graphical Abstract
  • -modified PNA monomers (Figure 5) slightly reduced PNA binding affinity, with ᴅ-amino acids being somewhat better accommodated in the backbone than ʟ-amino acids and ᴅ-Lys being the only α-backbone modification that slightly increased PNA’s binding affinity to complementary DNA (but not RNA) [67]. Circular
  • dichroism studies showed that the ᴅ-Lys modification induced a right-handed helical conformation favorable for DNA binding while the ʟ-Lys modification induced a left‐handed helical conformation that disfavored PNA binding to DNA [69]. Interestingly, a crystal structure of PNA having three α-ᴅ-Lys
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Published 19 Jul 2021

Synthesis of 10-O-aryl-substituted berberine derivatives by Chan–Evans–Lam coupling and investigation of their DNA-binding properties

  • Peter Jonas Wickhorst,
  • Mathilda Blachnik,
  • Denisa Lagumdzija and
  • Heiko Ihmels

Beilstein J. Org. Chem. 2021, 17, 991–1000, doi:10.3762/bjoc.17.81

Graphical Abstract
  • 5a–e in the presence of ct DNA were examined with flow linear dichroism (LD) and circular dichroism (CD) spectroscopy (Figure 5, Figure S6, Supporting Information File 1). The binding of ligands 5a–e resulted in the development of negative LD signals at 350–355 nm and 420–429 nm clearly indicating an
  • = 77.2 ppm). Elemental analyses: HEKAtech EUROEA combustion analyzer, determined by Rochus Breuer, Organische Chemie I, Universität Siegen. Mass spectra (ESI): Finnigan LCQ Deca (U = 6 kV; working gas: Ar; auxiliary gas: N2; temperature of the capillary: 200 °C). Circular dichroism (CD) and linear
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Published 04 May 2021

Beyond ribose and phosphate: Selected nucleic acid modifications for structure–function investigations and therapeutic applications

  • Christopher Liczner,
  • Kieran Duke,
  • Gabrielle Juneau,
  • Martin Egli and
  • Christopher J. Wilds

Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76

Graphical Abstract
  • '-stereoisomer of FANA, FRNA also demonstrates improved binding to RNA, relative to DNA [185]. Circular dichroism spectra of FANA/RNA and ANA/RNA duplexes show similarity to that of DNA/RNA [178][183]. Both ANA and FANA demonstrate good stability to nucleases [183][186]. Hybrid duplexes of ANA and FANA with
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Published 28 Apr 2021

Synthesis and properties of oligonucleotides modified with an N-methylguanidine-bridged nucleic acid (GuNA[Me]) bearing adenine, guanine, or 5-methylcytosine nucleobases

  • Naohiro Horie,
  • Takao Yamaguchi,
  • Shinji Kumagai and
  • Satoshi Obika

Beilstein J. Org. Chem. 2021, 17, 622–629, doi:10.3762/bjoc.17.54

Graphical Abstract
  • affected the ΔTm values, though further investigations are needed for the details. CD spectral analyses of duplexes modified with GuNA[Me]-G To analyze the structures of the duplexes containing GuNA[Me], circular dichroism (CD) spectra were measured for ON2/ssRNA and ON2/ssDNA duplexes (Figure 2). The CD
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Published 04 Mar 2021

Biochemistry of fluoroprolines: the prospect of making fluorine a bioelement

  • Vladimir Kubyshkin,
  • Rebecca Davis and
  • Nediljko Budisa

Beilstein J. Org. Chem. 2021, 17, 439–460, doi:10.3762/bjoc.17.40

Graphical Abstract
  • dichroism, which assesses the backbone folding [121][122]. Changes in the denaturing conditions can be tracked by circular dichroism or fluorescence-based assays very easily. Alterations in the regular fold would usually be associated with alterations in the energy of the folding. These observations created
  • stability of proteins containing fluoroprolines In the context of biochemical science, it is common to assume that structural changes and stability differences correlate with each other. For a protein, an overall sum of the secondary structures can be easily evaluated by chiroptic methods, such as circular
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Published 15 Feb 2021

Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

  • Michał M. Więcław and
  • Bartłomiej Furman

Beilstein J. Org. Chem. 2021, 17, 115–123, doi:10.3762/bjoc.17.12

Graphical Abstract
  • an attempt at resolving this problem by means of the electronic circular dichroism (ECD) technique. We recorded an ECD spectrum of both compounds and compared it with simulated spectra, generated for both possible diastereomers (2-(R) and 2-(S)) using computational chemistry software. Unfortunately
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Published 13 Jan 2021

Supramolecular polymerization of sulfated dendritic peptide amphiphiles into multivalent L-selectin binders

  • David Straßburger,
  • Svenja Herziger,
  • Katharina Huth,
  • Moritz Urschbach,
  • Rainer Haag and
  • Pol Besenius

Beilstein J. Org. Chem. 2021, 17, 97–104, doi:10.3762/bjoc.17.10

Graphical Abstract
  • 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 dendritic building block equipped with eight sulfate groups and trigger the formation
  • the effect of sulfate modification on the self-assembly properties of the dendritic peptide amphiphiles were performed using circular dichroism (CD) spectroscopy and electron transmission microscopy (TEM) as well as cryogenic TEM. Finally, the binding affinity of the sulfated supramolecular polymers
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Published 12 Jan 2021

Circularly polarized luminescent systems fabricated by Tröger's base derivatives through two different strategies

  • Cheng Qian,
  • Yuan Chen,
  • Qian Zhao,
  • Ming Cheng,
  • Chen Lin,
  • Juli Jiang and
  • Leyong Wang

Beilstein J. Org. Chem. 2021, 17, 52–57, doi:10.3762/bjoc.17.6

Graphical Abstract
  • and applied in practice [4][5][6]. Among them, the fluorescent materials emitting circularly polarized luminescence (CPL) have attracted intensive interest owing to their wide applications in various researching fields including 3D displays, chiroptical materials, and so on [7][8][9][10]. Circular
  • dichroism (CD) absorption spectra reflect the chirality of the fluorescent materials in the ground state, and circularly polarized luminescence (CPL) spectra reflect the chirality of fluorescent materials in the excited electronic state. Therefore, the CD and CPL spectrum are the two most important tools to
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Published 06 Jan 2021

Synthesis, crystal structures and properties of carbazole-based [6]helicenes fused with an azine ring

  • Daria I. Tonkoglazova,
  • Anna V. Gulevskaya,
  • Konstantin A. Chistyakov and
  • Olga I. Askalepova

Beilstein J. Org. Chem. 2021, 17, 11–21, doi:10.3762/bjoc.17.2

Graphical Abstract
  • scientific interest for decades [1][2][3][4][5][6][7][8][9][10][11]. Compared to other planar π-conjugated systems, helicenes are more thermally stable and soluble in common organic solvents [9]. This fact together with the exceptionally high values of specific optical rotation and strong circular dichroism
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Published 04 Jan 2021

Incorporation of a metal-mediated base pair into an ATP aptamer – using silver(I) ions to modulate aptamer function

  • Marius H. Heddinga and
  • Jens Müller

Beilstein J. Org. Chem. 2020, 16, 2870–2879, doi:10.3762/bjoc.16.236

Graphical Abstract
  • spectroscopy To evaluate whether the Ag(I)-mediated base pairs are indeed formed in the aptamer derivatives, melting curves and circular dichroism (CD) spectra were recorded in the presence of increasing amounts of Ag(I). The DNA melting is expected to occur when the loop structure of the aptamers opens up. In
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Published 25 Nov 2020

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

Graphical Abstract
  • the absence of ds26 as clearly indicated by only a small decrease of the melting temperature of ΔΔTm = 1.8 °C (Figure 2; cf. Supporting Information File 1, Figure S4). CD spectroscopy The interactions of the ligands 4a–e with G4-DNA 22AG and a2 were also examined with circular dichroism (CD
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Published 18 Nov 2020

Enzyme-instructed morphological transition of the supramolecular assemblies of branched peptides

  • Dongsik Yang,
  • Hongjian He and
  • Bing Xu

Beilstein J. Org. Chem. 2020, 16, 2709–2718, doi:10.3762/bjoc.16.221

Graphical Abstract
  • transition. B) TEM images and the schematic illustration of the proteinase K-catalyzed transformation of the micelles of the branched peptide 1 to nanofibers. A) LC–MS spectrum of the proteolytic products after 1 (5 mM) was incubated with proteinase K (5 U/mL) for 24 h. B) Time-dependent circular dichroism
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Published 04 Nov 2020

Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

  • Poulami Jana,
  • Filip Šupljika,
  • Carsten Schmuck and
  • Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

Graphical Abstract
  • the DNA/RNA conjugate NDI-GCP2 showed also aggregation along the ds-polynucleotide and AFM and DLS demonstrated that NDI-GCP2 has pronounced ds-DNA condensation ability. Keywords: AFM; circular dichroism; DNA/RNA recognition; fluorescence; guanidinio-carbonyl-pyrrole; naphthalene diimide
  • monitoring, fluorescence is still the most popular method [8][9][10][11]. However, many new techniques or established ones with increased sensitivity are constantly improved or developed to report complementary to fluorescence. For instance, circular dichroism (CD) spectropolarimetry, highly sensitive to
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Published 08 Sep 2020

Muyocopronones A and B: azaphilones from the endophytic fungus Muyocopron laterale

  • Ken-ichi Nakashima,
  • Junko Tomida,
  • Tomoe Tsuboi,
  • Yoshiaki Kawamura and
  • Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 2100–2107, doi:10.3762/bjoc.16.177

Graphical Abstract
  • configurations were determined using the modified Mosher’s method and through comparisons of experimental and calculated electronic circular dichroism data. In addition, muyocopronone B (2) was found to exhibit a weak antibacterial activity against some Gram-positive bacteria. Keywords: azaphilones; endophytic
  • wavelength around 360 nm corresponding to 7S and 7R [22][23][24]. Therefore, positive Cotton effects at 325 and 355 nm in the electronic circular dichroism (ECD) spectrum of 1 indicated that the absolute configuration of the C-7 position was S (Figure 3). Furthermore, the coupling constant between H-10/H-11
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Published 28 Aug 2020

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

  • Annike Weißenstein,
  • Myroslav O. Vysotsky,
  • Ivo Piantanida and
  • Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

Graphical Abstract
  • )-polynucleotides. The DNA/RNA binding-induced circular dichroism (ICD) response of NDI at 450–550 nm strongly depended on the length and rigidity of the linker to the amino acid unit, which controls the orientation of the NDI unit inside within the intercalative binding site. The ICD selectivity also depends on
  • the type of polynucleotide, thus the studied NDI dyes act as dual fluorimetric/ICD probes for sensing the difference between here used GC-DNA, AT-DNA and AU-RNA. Keywords: amino acid–fluorophore conjugate; circular dichroism; DNA/RNA recognition; fluorescence; intercalation; naphthalene diimide
  • cations and water molecules from the DNA/RNA grooves [44][45] by side arms interacting with the grooves and thereby supporting the binding. Circular dichroism experiments CD spectroscopy is an ideal method to get insight into the changes of the polynucleotide secondary structure upon binding of small
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Published 19 Aug 2020

pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide

  • Goutam Ghosh and
  • Gustavo Fernández

Beilstein J. Org. Chem. 2020, 16, 2017–2025, doi:10.3762/bjoc.16.168

Graphical Abstract
  • fractal-like morphologies, as verified by circular dichroism (CD), Fourier-transform infrared (FTIR) spectroscopy, thioflavin T (ThT) fluorescence spectroscopy assay, and atomic force microscopy (AFM). Upon changing the pH value (using pH 5.5 and 13.0), PEP-1 forms different types of secondary structures
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Published 17 Aug 2020

Copper catalysis with redox-active ligands

  • Agnideep Das,
  • Yufeng Ren,
  • Cheriehan Hessin and
  • Marine Desage-El Murr

Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77

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  • precursors affords both enantiomers Δ-10 (from CuClO4) and Λ-10 from (Cu(CH3CN)4PF6). UV–vis and circular dichroism spectroscopic studies evidence that the helical chirality exhibited by these two catalysts could be reversed by redox stimuli. These complexes could perform enantioselective Michael addition
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Published 24 Apr 2020

Synthesis and circularly polarized luminescence properties of BINOL-derived bisbenzofuro[2,3-b:3’,2’-e]pyridines (BBZFPys)

  • Ryo Takishima,
  • Yuji Nishii,
  • Tomoaki Hinoue,
  • Yoshitane Imai and
  • Masahiro Miura

Beilstein J. Org. Chem. 2020, 16, 325–336, doi:10.3762/bjoc.16.32

Graphical Abstract
  • -shifted than 4a despite such a sterically demanding group usually disturbs intermolecular stacking interactions. Subsequently, the chiroptical properties of the synthesized compounds were evaluated (Figure 2 and Figure 3, Table 2). The circular dichroism (CD) spectra in CHCl3 solutions showed apparent
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Published 06 Mar 2020

Absolute configurations of talaromycones A and B, α-diversonolic ester, and aspergillusone B from endophytic Talaromyces sp. ECN211

  • Ken-ichi Nakashima,
  • Junko Tomida,
  • Takao Hirai,
  • Yoshiaki Kawamura and
  • Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 290–296, doi:10.3762/bjoc.16.28

Graphical Abstract
  • planar structures of 1 and 2 were elucidated by extensive spectroscopic analyses. Furthermore, the absolute configurations of 1–4 were determined by single-crystal X-ray diffraction and electronic circular dichroism spectroscopy (ECD). In addition, the crystallographic data for 5 were updated for the
  • been omitted for clarity. b) Electronic circular dichroism spectra of 1 (black solid line) and 2 (red dashed line). a) ORTEP drawing of 3, with thermal ellipsoids indicating 50% probability. b) Electronic circular dichroism spectra of 3 (black solid line) and 4 (red dashed line). a) ORTEP drawing of 5
  • , with thermal ellipsoids indicating 50% probability. b) Electronic circular dichroism spectrum of 5. 1H (400 MHz) and 13C (100 MHz) NMR data for 1 and 2 in CDCl3. Supporting Information Supporting Information File 265: A phytogenic tree for ECN211 and related species and NMR spectra of 1 and 2
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Published 28 Feb 2020

Reversible photoswitching of the DNA-binding properties of styrylquinolizinium derivatives through photochromic [2 + 2] cycloaddition and cycloreversion

  • Sarah Kölsch,
  • Heiko Ihmels,
  • Jochen Mattay,
  • Norbert Sewald and
  • Brian O. Patrick

Beilstein J. Org. Chem. 2020, 16, 111–124, doi:10.3762/bjoc.16.13

Graphical Abstract
  • –d were further investigated by circular dichroism (CD) and flow linear dichroism (LD) spectroscopy [74][75] in phosphate buffer at different ligand-to-DNA ratios (LDR). The mixtures of compounds 3a–d with ct DNA showed clear induced circular dichroism (ICD) and LD bands in the absorption region of
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Published 23 Jan 2020

Photocontrolled DNA minor groove interactions of imidazole/pyrrole polyamides

  • Sabrina Müller,
  • Jannik Paulus,
  • Jochen Mattay,
  • Heiko Ihmels,
  • Veronica I. Dodero and
  • Norbert Sewald

Beilstein J. Org. Chem. 2020, 16, 60–70, doi:10.3762/bjoc.16.8

Graphical Abstract
  • derivatives was proven by CD titration experiments. The resulting induced circular dichroism (ICD) bands of the bound ligands, together with the photometric determination of the dsDNA melting temperature, revealed a significant stabilization of the DNA upon association with the ligand. The (Z)-azobenzene
  • photoswitchable polyamides From a pool of new azobenzene-containing polyamides, we present the most promising photoswitchable representatives containing six or eight Im/Py units (P1, P2, and P3, Scheme 1). Their binding capability to dsDNA was analyzed by titration and temperature-dependent circular dichroism
  • % P1; 67% P2; after 1 d: 76% P3). Analysis of polyamide–DNA interaction by induced circular dichroism CD spectroscopic analysis is suitable for the characterization of DNA minor groove binders, providing semiquantitative information about binding affinity and thermal stability of the target dsDNA [47
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Published 09 Jan 2020
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