Halogen-bonding-induced diverse aggregation of 4,5-diiodo-1,2,3-triazolium salts with different anions

Xingyu Xu,
Shiqing Huang,
Zengyu Zhang,
Lei Cao and
Xiaoyu Yan

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Published 13 Jan 2020

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1. Graphical Abstract
2. Figure 1: 1,2,3-Triazole based XB donors: 1,2,3-triazole A, 1,2,3-triazolium B, 1,2,3-triazolylidene C and di...
  
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3. Scheme 1: Synthesis of 4,5-diiodo-1,3-dimesityl-1,2,3-triazolium with iodide, Mes: 2,4,6-Me₃C₆H₂.
  
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4. Scheme 2: Synthesis of 4,5-diiodo-1,3-dimesityl-1,2,3-triazolium with different anion.
  
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5. Figure 2: Packing structure of 2-I (top), 2-Br (middle) and 2-Cl (bottom). Hydrogen atoms have been omitted f...
  
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6. Figure 3: Packing structure of 2-BF₄. Hydrogen atoms have been omitted for clarity.
  
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7. Figure 4: Packing structure of 2-OAc. Hydrogen atoms and solvent molecules have been omitted for clarity.
  
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8. Figure 5: Packing structure of 2-TFA. Hydrogen atoms and disorder of fluorine atoms have been omitted for cla...
  
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9. Figure 6: Packing structure of 2-I^.1.5I₂. Hydrogen atoms have been omitted for clarity.
  
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10. Figure 7: Packing structure of 2-I^.3.5I₂. Hydrogen atoms have been omitted for clarity.
  
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11. Figure 8: Packing structure of 2-BF₄^.0.5bpy. Hydrogen atoms and dichloromethane have been omitted for clarity....
  
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12. Figure 9: 1,2,3-Triazole-based halogen model calculation: electrostatic potential surfaces mapped on total de...
  
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Beilstein J. Org. Chem. 2020, 16, 78–87, doi:10.3762/bjoc.16.10

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The interaction between cucurbit[8]uril and baicalein and the effect on baicalein properties

Xiaodong Zhang,
Jun Xie,
Zhiling Xu,
Zhu Tao and
Qianjun Zhang

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Published 10 Jan 2020

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1. Graphical Abstract
2. Figure 1: Chemical structures of baicalein (left), cucurbit[8]uril (right).
  
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3. Figure 2: The possible interaction model for Q[8] and baicalein.
  
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4. Figure 3: ¹H NMR spectra (400 MHz) of Q[8] (a), baicalein (b) and BALE–Q[8] (1:1) (c) recorded in DCl.
  
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5. Figure 4: The absorption spectra of BALE upon the addition of Q[8] under different conditions [10 mol·L⁻¹ HCl...
  
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6. Figure 5: IR spectra of Q[8] (a), BALE (b), a physical mixture of Q[8]-BALE (N_Q[8]/N_BALE = 1:1) (c) and the B...
  
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7. Figure 6: DTA spectra of BALE (a), Q[8] (b), a physical mixture Q[8]-BALE (N_Q[8]/N_BALE = 1:1) (c) and the BAL...
  
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8. Figure 7: The stability curve of UV–vis absorption obtained for an isoconcentration of BALE and the BALE–Q[8]...
  
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9. Figure 8: The phase solubility graph obtained for BALE in Q[8] at λ = 270 nm.
  
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10. Figure 9: The clearance rate curve (A) and clearance time curve (B) of ABTS^+· upon increasing the concentrati...
  
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11. Figure 10: The release curves of BALE and BALE–Q[8].
  
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Beilstein J. Org. Chem. 2020, 16, 71–77, doi:10.3762/bjoc.16.9

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Photocontrolled DNA minor groove interactions of imidazole/pyrrole polyamides

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

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Published 09 Jan 2020

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1. Graphical Abstract
2. Scheme 1: Pyrrole–imidazole–azobenzene polyamides and the dsDNA target sequences employed in this study.
  
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3. Scheme 2: Building blocks required for the synthesis of the photoswitchable Im/Py polyamides. A) Fmoc–Azo–OH 1...
  
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4. Figure 1: Section of the ¹H NMR (600 MHz) spectrum of polyamide P1. A) Initial thermal equilibrium. B) After ...
  
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5. Figure 2: E/Z isomer ratio of the polyamides P1–P3. Values were obtained from the respective ¹H NMR experimen...
  
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6. Figure 3: Titration experiments of target DNA sequences with P1–P3 in the photostationary Z-state and the the...
  
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7. Figure 4: Titration of DNA containing single mutations (in bold) with P1–P3 in the photostationary Z-state an...
  
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Beilstein J. Org. Chem. 2020, 16, 60–70, doi:10.3762/bjoc.16.8

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Understanding the role of active site residues in CotB2 catalysis using a cluster model

Keren Raz,
Ronja Driller,
Thomas Brück,
Bernhard Loll and
Dan T. Major

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Published 08 Jan 2020

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1. Graphical Abstract
2. Scheme 1: Mechanism for formation of cyclooctat-9-en-7-ol, published similarly in [42].
  
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3. Figure 1: Computed electronic energy profiles (kcal/mol) for the CotB2 cyclase mechanism. The calculations us...
  
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4. Figure 2: Intermediates A–I in the active site model. Interactions are marked by dashed orange lines, the int...
  
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5. Figure 3: TS structures TS_A_B–TS_G/H_I in the active site model. Interactions are marked by dashed orange li...
  
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6. Figure 4: Comparison between gas phase and active site model conformations. A) Intermediate D. B) Intermediat...
  
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Beilstein J. Org. Chem. 2020, 16, 50–59, doi:10.3762/bjoc.16.7

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Light-controllable dithienylethene-modified cyclic peptides: photoswitching the in vivo toxicity in zebrafish embryos

Sergii Afonin,
Oleg Babii,
Aline Reuter,
Volker Middel,
Masanari Takamiya,
Uwe Strähle,
Igor V. Komarov and
Anne S. Ulrich

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Published 07 Jan 2020

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1. Graphical Abstract
2. Figure 1: DAE photoswitch and photoswitchable peptides explored in this study. (A) The reversible photoisomer...
  
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3. Figure 2: Two versions of the D. rerio embryotoxicity assay for DAE-modified peptides: timelines, peptide pho...
  
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4. Figure 3: The in vivo toxicity against D. rerio embryos appears to be correlated with the empirical hydrophob...
  
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5. Figure 4: D. rerio embryotoxicity of GS 1 and the photoswitchable analogues 2–20 correlated with their in vit...
  
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6. Figure 5: Phototherapeutic cytotoxic action against HeLa cells of GS 1 and its photoswitchable analogues 2–20...
  
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Beilstein J. Org. Chem. 2020, 16, 39–49, doi:10.3762/bjoc.16.6

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Microwave-assisted synthesis of 2-substituted 4,5,6,7-tetrahydro-1,3-thiazepines from 4-aminobutanol

María C. Mollo,
Natalia B. Kilimciler,
Juan A. Bisceglia and
Liliana R. Orelli

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Published 06 Jan 2020

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1. Graphical Abstract
2. Scheme 1: Chemical shift data for N-thiobenzoylpiperidine and compound 4a.
  
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3. Scheme 2: PPSE promoted ring closure reactions of amido- and thioamido alcohols.
  
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Beilstein J. Org. Chem. 2020, 16, 32–38, doi:10.3762/bjoc.16.5

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Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes

Andreas H. Heindl and
Hermann A. Wegner

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Published 03 Jan 2020

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1. Graphical Abstract
2. Figure 1: 1,3,5-Tris(arylazo)benzenes as individually switchable multistate photoswitches: previous [11,12] and pres...
  
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3. Scheme 1: Synthetic strategy towards 1,3,5-tris(arylazo)benzenes 3 based on consecutive Baeyer–Mills reaction...
  
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4. Scheme 2: Preparation of tris(arylazo)benzenes 3 by Pd-catalyzed cross-coupling reactions of N-Boc-arylhydraz...
  
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5. Scheme 3: Synthesis of azobenzene building block 8.
  
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6. Scheme 4: Synthesis of 1,3-bis(4-methoxyphenylazo)-5-phenylazobenzene (14).
  
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7. Scheme 5: Synthesis of unsymmetrical tris(arylazo)benzenes 3a/3b using Pd-catalyzed coupling reactions and Cu...
  
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8. Scheme 6: Coupling reactions of 15 with the corresponding arylhydrazides to access monocoupled (16a/16b) and ...
  
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9. Figure 2: a) UV–vis spectra of tris(arylazo)benzenes 3a/3b in ethanol. b) Reversible photoisomerization of 3a...
  
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Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4

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Functionalization of the imidazo[1,2-a]pyridine ring in α-phosphonoacrylates and α-phosphonopropionates via microwave-assisted Mizoroki–Heck reaction

Damian Kusy,
Agata Wojciechowska,
Joanna Małolepsza and
Katarzyna M. Błażewska

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Published 03 Jan 2020

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1. Graphical Abstract
2. Figure 1: Substrates used for the Mizoroki–Heck reaction in this study.
  
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3. Figure 2: Structures of the identified side products 4 and 5.
  
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4. Scheme 1: Scope of the method for analogs derived from 1 and 2. The ratio of isomers is given (E/Z or β/α) in...
  
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5. Scheme 2: Dealkylation of fluorinated analog 23 under the Mizoroki–Heck reaction conditions.
  
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Beilstein J. Org. Chem. 2020, 16, 15–21, doi:10.3762/bjoc.16.3

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Synthesis of C-glycosyl phosphonate derivatives of 4-amino-4-deoxy-α-ʟ-arabinose

Lukáš Kerner and
Paul Kosma

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Published 02 Jan 2020

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1. Graphical Abstract
2. Figure 1: Modification of lipid A by ArnT.
  
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3. Scheme 1: Phosphonate and glycal synthesis.
  
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4. Scheme 2: Synthesis of methyl phosphonate 11 and octyl phosphonates 16 and 17.
  
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Beilstein J. Org. Chem. 2020, 16, 9–14, doi:10.3762/bjoc.16.2

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Extension of the 5-alkynyluridine side chain via C–C-bond formation in modified organometallic nucleosides using the Nicholas reaction

Renata Kaczmarek,
Dariusz Korczyński,
James R. Green and
Roman Dembinski

Letter
Published 02 Jan 2020

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1. Graphical Abstract
2. Scheme 1: Preparation of (2'-deoxy)-5-alkynyluridines 2 and 3, their dicobalt hexacarbonyl derivatives 4 and 5...
  
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3. Figure 1: Structures of nucleosides 6 and 7, products of the Nicholas reaction.
  
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Beilstein J. Org. Chem. 2020, 16, 1–8, doi:10.3762/bjoc.16.1

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