Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes

• Henrik Hupatz,
• Marius Gaedke,
• Hendrik V. Schröder,
• Julia Beerhues,
• Arto Valkonen,
• Fabian Klautzsch,
• Sebastian Müller,
• Felix Witte,
• Kari Rissanen,
• Biprajit Sarkar and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2020, 16, 2576–2588, doi:10.3762/bjoc.16.209

• potential of tailor-made redox-active crown ethers for the development of new molecular switches. Yet, a careful design of tailor-made redox-active crown ethers is of great importance for tuning the crown ether binding and redox properties to achieve the desired molecular structure and switching mode, which

Computational tools for drawing, building and displaying carbohydrates: a visual guide

• Kanhaya Lal,
• Rafael Bermeo and
• Serge Perez

Beilstein J. Org. Chem. 2020, 16, 2448–2468, doi:10.3762/bjoc.16.199

• ) package. These algorithms are useful to visualize complex cyclic molecules and multi-branched polysaccharides.{Cross, 2009 #69} PaperChain displays rings in a molecular structure with a polygon and colours them according to the ring pucker. The other algorithm (Twister) traces glycosidic bonds in a ribbon

Host–guest interaction of cucurbit[8]uril with oroxin A and its effect on the properties of oroxin A

• Zhishu Zeng,
• Jun Xie,
• Guangyan Luo,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 2332–2337, doi:10.3762/bjoc.16.194

• −1. The results of the UV absorption spectrum analysis showed that Q[8] enhanced the cumulative release of OA in artificial gastric juice by 2.3-fold, but had no effect on its antioxidant activity. The molecular structure of OA (A) and Q[8] (B). 1H NMR titration of OA with Q[8] were performed in D2O

Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes

• Thomas Schneider,
• Michael Keim,
• Bianca Seitz and
• Gerhard Maas

Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173

• -(dimethylamino)indenes as the major products. Various other synthetic applications of these reactive propyn-1-iminium salts will be reported in due course. Solid-state molecular structure of 11 (ORTEP plot). Solid-state molecular structure of 12c (ORTEP plot). Solid-state molecular structure of 12d (ORTEP plot

• . Synthesis and solid-state molecular structure (ORTEP plot) of pentafulvene 19; selected bond distances (Å), see molecule plot for atom numbering: C8‒C7 1.370(2), C7‒C17 1.481(2), C17‒C18 1.343(2), C18‒C5 1.471(2), C5‒C6 1.374(2), C6‒C7 1.496(2). Proposed mechanistic pathway leading to fulvene 19

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

• bind specifically to multistranded β-sheets [62][63]. PEP-1 is nonemissive due to the absence of chromophores in its molecular structure, whereas ThT shows a low fluorescence in PBS (pH 7.4) upon excitation at 440 nm. Interestingly, the fluorescence intensity of ThT significantly increases upon mixing

On the hydrolysis of diethyl 2-(perfluorophenyl)malonate

• Ilya V. Taydakov and
• Mikhail A. Kiskin

Beilstein J. Org. Chem. 2020, 16, 1863–1868, doi:10.3762/bjoc.16.153

• better precursors, but these esters are expensive, hardly accessible and can barely be used for large-scale preparation of 2-(perfluorophenyl)malonic acid (12). Phenylmalonic acids. Esters of fluorine-substituted 2-phenylmalonic acids. Molecular structure of 2-(perfluorophenyl)acetic acid (12). Synthesis

Synthesis and highly efficient light-induced rearrangements of diphenylmethylene(2-benzo[b]thienyl)fulgides and fulgimides

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Valerii V. Tkachev,
• Andrey N. Utenyshev,
• Olga Yu. Karlutova,
• Alexander D. Dubonosov,
• Vladimir A. Bren,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2020, 16, 1820–1829, doi:10.3762/bjoc.16.149

• structure of 3Z. Thermal ellipsoids are drawn on the 30% probability level. Selected bond lengths (Å): C(3)–C(4) = 1.476(2), С(4)=С(5) = 1.360(2), С(3)=С(14) = 1.356(2). Molecular structure of 3E. Thermal ellipsoids are drawn on the 30% probability level. Selected bond lengths (Å): C(3)–C(4) = 1.461(2), С(4

• fulgide 3Z in acetonitrile solution before (1) and after irradiation with light of 436 nm for 30 (2), 60 (3) and 100 (4) s (2.5 × 10−5 M, T = 293 K). Molecular structure of photoproduct cis-9C’. Thermal ellipsoids are drawn on the 30% probability level. Selected bond lengths (Å): С(5)–С(16) = 1.531(3), С

• crystallographic data for the 3Z, 3E and 9, respectively. These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk. Molecular

Clickable azide-functionalized bromoarylaldehydes – synthesis and photophysical characterization

• Dominik Göbel,
• Marius Friedrich,
• Enno Lork and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2020, 16, 1683–1692, doi:10.3762/bjoc.16.139

• previous deprotection reactions, fluorene 21 was converted by means of a three-step sequence to the desired azide-functionalized 7-bromofluorene-2-carbaldehyde 5 in 86% yield and an overall yield of 45% (starting from fluorene). The molecular structure of 5 could be verified by X-ray diffraction (XRD, see

• h, 91%; h) 1) DPPA, DBU, PhMe, 25 °C, 15 h; 2) NaN3, PhMe, 60 °C, 4 h, 87%; i) 1) MeOTf, CH2Cl2, 25 °C, 2.5 h; 2) NaBH4, THF/MeOH 4:1 v/v, 0 °C, 2.5 h; 3) oxalic acid, THF/H2O 4:1 v/v, 25 °C, 20 h, 86%. Overall yield to 5: 45% (8 steps). The molecular structure of 5 shows 50% probability ellipsoids

Models of necessity

• Timothy Clark and
• Martin G. Hicks

Beilstein J. Org. Chem. 2020, 16, 1649–1661, doi:10.3762/bjoc.16.137

• reverse direction: Lewis structures are drawn or defined by a line notation such as SMILES, converted by one of several algorithms into a realistic 3D molecular structure and the resulting structure used as input for a quantum mechanical calculation. What quantum mechanics does far better than rationalize

• models and descriptions are poorly suited for the more varied interactions involved in, for instance, self-organization in technical systems. Requirement (2) results from the conformation problem. Any technique or model that requires a specific 3D molecular structure must deal with conformational

Fluorohydration of alkynes via I(I)/I(III) catalysis

• Jessica Neufeld,
• Constantin G. Daniliuc and
• Ryan Gilmour

Beilstein J. Org. Chem. 2020, 16, 1627–1635, doi:10.3762/bjoc.16.135

• ]. (A) Synthetic routes to α-fluoroketones from silyl enol ethers or acetophenone derivatives. (B) Selected Au-catalysed syntheses of α-fluoroketones from alkynes. (C) This work: synthesis of α-fluoroketones from pentynyl benzoates via I(I)/I(III) catalysis. X-ray molecular structure of compound 2

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• ), used for all further characterizations, that the crosslinked polymers synthesized by both methods exhibited a very close degradation path and, consequently, the same molecular structure was expected. The largest mass loss started above 300 °C for both βNS and the relative maximum rate peak was located

Synthesis, antiinflammatory activity, and molecular docking studies of bisphosphonic esters as potential MMP-8 and MMP-9 inhibitors

• Abimelek Cortes-Pacheco,
• María Adelina Jiménez-Arellanes,
• Francisco José Palacios-Can,
• José Antonio Valcarcel-Gamiño,
• Rodrigo Said Razo-Hernández,
• María del Carmen Juárez-Vázquez,
• Adolfo López-Torres and
• Oscar Abelardo Ramírez-Marroquín

Beilstein J. Org. Chem. 2020, 16, 1277–1287, doi:10.3762/bjoc.16.108

• ) database, which compares the molecular structure of test compounds vs a large training set of experimental bioactive or inactive compounds [21]. The results of the prediction are summarized as probability of activity (Pa) and probability of inactivity (Pi) values, both ranging from 0 to 1 (Figure 2), where

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• is to employ both donor and acceptor moieties in a single molecular structure [1][2][3][4]. Quinazoline is a planar aromatic heterocyclic compound with the fused bicyclic structure consisting of benzene and pyrimidine rings. Quinazoline derivatives were investigated and used in medicinal applications

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• those found in related examples reported in the literature and do not show additional noteworthy features [28][29][30]. From the observation of the molecular structure of 4a, it is clear how the geometrical constraints of the ligands in complexes 3 establish unequivocally the stereoselective formation

A simple and easy to perform synthetic route to functionalized thienyl bicyclo[3.2.1]octadienes

• Dragana Vuk,
• Irena Škorić,
• Valentina Milašinović,
• Krešimir Molčanov and
• Željko Marinić

Beilstein J. Org. Chem. 2020, 16, 1092–1099, doi:10.3762/bjoc.16.96

• -isomers of compounds 3–7. Molecular structure of compound trans-6. Displacement ellipsoids are drawn for the probability of 30% and hydrogen atoms are shown as spheres of arbitrary radii. Crystal packing of trans-6. (a) Chain parallel to [100] and (b) chain parallel to [010]. 1H NMR spectra (CDCl3) of

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• devices [1]. Nowadays, organic compounds exhibiting thermally activated delayed fluorescence (TADF) are widely used as emitters for OLEDs [2]. The great interest in TADF emitters is mainly explained by their heavy-atoms-free molecular structure and 100% theoretical limit of internal quantum efficiency

Efficient synthesis of piperazinyl amides of 18β-glycyrrhetinic acid

• Dong Cai,
• ZhiHua Zhang,
• Yufan Meng,
• KaiLi Zhu,
• LiYi Chen,
• ChangXiang Yu,
• ChangWei Yu,
• ZiYi Fu,
• DianShen Yang and
• YiXia Gong

Beilstein J. Org. Chem. 2020, 16, 798–808, doi:10.3762/bjoc.16.73

• -glycyrrhetinic acid derivative 18. The molecular structure of compound 18 in the crystalline state is shown in Figure 3. In this crystal structure, there is an orientational disorder of the m-fluorophenyl moiety due to the rotation of a single bond. Details for the crystal structure determinations are given in

One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

• Ji Ma,
• Yubin Fu,
• Junzhi Liu and
• Xinliang Feng

Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72

• 1 were obtained by slow evaporation from a carbon disulfide solution, allowing us to disclose the molecular structure by X-ray crystallography (Figure 2a). As shown in Figure 2a, the crystal structure of 1 clearly displayed a nonplanar conformation, resulting from steric repulsion between the phenyl

Reaction of indoles with aromatic fluoromethyl ketones: an efficient synthesis of trifluoromethyl(indolyl)phenylmethanols using K₂CO₃/n-Bu₄PBr in water

• Thanigaimalai Pillaiyar,
• Masoud Sedaghati and
• Gregor Schnakenburg

Beilstein J. Org. Chem. 2020, 16, 778–790, doi:10.3762/bjoc.16.71

• reaction with ketones.a Substrate scope of the reaction with indoles.a Supporting Information Materials and methods and detailed synthetic procedures and spectroscopic data of all compounds. Figure S1: ORTEP-type plot of the molecular structure of 3a, Figures S2–S25: NMR spectra, Tables S1–S3: Crystal

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• charge from The Cambridge Crystallographic Data Centre via http://www.ccdc.cam.ac.uk/data_request/cif. Triptycene as a scaffold and selected porphyrin and BODIPY arrays. Single crystal X-ray structure of triptycene 5. (a) Molecular structure of 5 in the crystal with hydrogen atoms and minor disorder

Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates

• Marcin Kaźmierczak and
• Henryk Koroniak

Beilstein J. Org. Chem. 2020, 16, 756–762, doi:10.3762/bjoc.16.69

• 60:40 → 50:50). Chemical structure of PyFluor, PBSF and SulfoxFluor. Chemical structure bases. Molecular structure of compound (1R,2S)-14c (ORTEP image). Synthesis of 5. Synthesis of 11. Synthesis of 13 and 14. Synthesis of 15. aConditions are given in the Experimental section. Optimization of

Synthesis of triphenylene-fused phosphole oxides via C–H functionalizations

• Md. Shafiqur Rahman and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2020, 16, 524–529, doi:10.3762/bjoc.16.48

• cyclization under the same conditions to give the corresponding product 8c albeit in a somewhat lower yield of 40%. The triphenylene-fused phosphole oxide 8a was recrystallized from CH2Cl2, and the molecular structure was unambiguously confirmed by single crystal X-ray analysis (Figure 2) [31]. As can be seen

Ultrasonic-assisted unusual four-component synthesis of 7-azolylamino-4,5,6,7-tetrahydroazolo[1,5-a]pyrimidines

• Yana I. Sakhno,
• Maryna V. Murlykina,
• Oleksandr I. Zbruyev,
• Anton V. Kozyryev,
• Svetlana V. Shishkina,
• Dmytro Sysoiev,
• Vladimir I. Musatov,
• Sergey M. Desenko and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2020, 16, 281–289, doi:10.3762/bjoc.16.27

• ]pyrimidines via a cascade of elementary stages that is unusual for such transformations. Thus, we extended the molecular diversity of the compounds obtained by introducing an additional azolyl substituent to the pyrimidine ring. Alternative structures A and B for the tetrahydroazolopyrimidines 4. Molecular

• structure of ethyl 5-(4-bromophenyl)-3-cyano-7-((4-cyano-1H-pyrazol-5-yl)amino)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine-7-carboxylate (4g) obtained from X-ray diffraction data. Chains of 4g molecules in the crystal phase. Synthesis of tetrahydroazolopyrimidine derivatives. Various multicomponent

Synthesis, liquid crystalline behaviour and structure–property relationships of 1,3-bis(5-substituted-1,3,4-oxadiazol-2-yl)benzenes

• Afef Mabrouki,
• Malek Fouzai,
• Armand Soldera,
• Abdelkader Kriaa and
• Ahmed Hedhli

Beilstein J. Org. Chem. 2020, 16, 149–158, doi:10.3762/bjoc.16.17

• ]. The introduction of fluorine atoms in the molecular structure presents a successful strategy to control the liquid crystal proprieties. The element Fluorine presents the highest electronegativity, the lowest polarizability and a small radius. When bonded to carbon, it forms the strongest single bond

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering

• Eric J. N. Helfrich,
• Geng-Min Lin,
• Christopher A. Voigt and
• Jon Clardy

Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283

• potential with molecular structure is severely restricted. The canonical terpene biosynthetic pathway uses a single enzyme to form a cyclized hydrocarbon backbone followed by modifications with a suite of tailoring enzymes that can generate dozens of different products from a single backbone. This