Synthesis, structural characterization, and optical properties of benzo[f]naphtho[2,3-b]phosphoindoles

• Mio Matsumura,
• Takahiro Teramoto,
• Masato Kawakubo,
• Masatoshi Kawahata,
• Yuki Murata,
• Kentaro Yamaguchi,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2021, 17, 671–677, doi:10.3762/bjoc.17.56

• the pentacyclic ring is almost planar. Fluorescence spectroscopy data showed that the phosphole derivatives, such as phosphine oxide and the phospholium salt and borane complex exhibited photoluminescence in chloroform. Keywords: benzo[f]naphtho[2,3-b]phosphoindole; molecular structure; optical

• , molecular structure, and optical properties of 6-phenyl-6H-benzo[f]naphtho[2,3-b]phosphoindole (F) and the derivatives in which the phosphorus atom is chemically modified, such as a phospholium salt and the borane–phosphine complex. Results and Discussion Treatment of 3,3′-dibromo-2,2′-binaphthyl (1) [21

• recrystallization. The molecular structure of 2, determined through single-crystal X-ray diffraction analysis, is illustrated in Figure 2, and selected geometrical parameters are shown in Table 1. The results revealed that the naphthalene and fused phosphole rings are almost coplanar (mean deviation = 0.030 Å). The

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• (II) complex 17 [(L3)Cu(II)Cl2] was synthesized and characterized by X-ray analysis, FTIR and vis–NIR spectroscopy (for details see Supporting Information File 2). The molecular structure of the complex 17 is shown in Figure 4 and Figure 5. The basic experimental details and selected crystallographic

• . Proposed catalytic cycles for the amination of 4-bromophthalazinones of type 3 (Phthal: phthalazinone, PhthalBr: 4-bromophthalazinone, PhthalNR1R2: 4-aminophthalazinone). The phthalazinone derivatives that were used to test the complexation of Cu(II) ions. Structure of complex 17. Molecular structure of

Synthesis and physicochemical evaluation of fluorinated lipopeptide precursors of ligands for microbubble targeting

• Masayori Hagimori,
• Estefanía E. Mendoza-Ortega and
• Marie Pierre Krafft

Beilstein J. Org. Chem. 2021, 17, 511–518, doi:10.3762/bjoc.17.45

• proposed for the preparation of functional drug carriers for clinical applications [25][28][29]. In order to alleviate the steric hindrance effect of PEG chains, a novel spacer consisting of alternating serine–glycine sequences (SG)n was introduced between the ligand and lipid within the molecular

• structure [30]. These lipopeptides have a discrete molecular weight and are produced by Fmoc (fluorenylmethoxycarbonyl protecting group) SPPS, a procedure in which the peptide chain is assembled stepwise while attached to an insoluble resin support, which allows the easy removal of the byproducts at each

Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies

• Alexander Zika and
• Franziska Gröhn

Beilstein J. Org. Chem. 2021, 17, 166–185, doi:10.3762/bjoc.17.17

• particles, and information on the molecular structure was gained by UV–vis spectroscopy. Isothermal titration calorimetry (ITC) provided information on the thermodynamics and interaction forces in the supramolecular assembly formation. Keywords: electrostatic self-assembly; hydroxyflavylium

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

• band gaps (by ≈0.5 eV). In cases of pyrazine and pyridine-fused analogs, differences are not so noticeable. Experimental The synthetic procedures, HPLC, X-ray studies and spectra (1H and 13C NMR) of all new compounds can be found in Supporting Information File 1. Molecular structure of carbazole-based

Selected peptide-based fluorescent probes for biological applications

• Debabrata Maity

Beilstein J. Org. Chem. 2020, 16, 2971–2982, doi:10.3762/bjoc.16.247

• with nucleic acids. Reprinted with permission from [34]. Copyright (2012) American Chemical Society. A) Molecular structure of peptidic probe 1, Inset: HeLa cells incubated with peptide 1 (50 μM), showing an ATP responsive green fluorescence; B) fluorescence emission spectra of probe 1 (20.0 µM) (λex

• = 410 nm) with increasing concentration (0–10.0 µM) of ATP in 10 mM HEPES buffer, pH 7.4. Reproduced from [39] with permission from The Royal Society of Chemistry. A) Molecular structure of probe 2; B) fluorescence emission spectra for the titration of a 10 μM solution of 2 with p(dA·dT)2 in aqueous

• buffer (pH 7.4) (with base pair/2 molar ratios ranging from 0 to 4.0), inset: nuclei of HeLa cells stained with 2. Reprinted with permission from [34]. Copyright (2012) American Chemical Society. A) Molecular structure of 3; B) fluorescence emission spectra for the titration of a 10 μM solution of 3 with

Naphthalonitriles featuring efficient emission in solution and in the solid state

• Sidharth Thulaseedharan Nair Sailaja,
• Iván Maisuls,
• Jutta Kösters,
• Alexander Hepp,
• Andreas Faust,
• Jens Voskuhl and
• Cristian A. Strassert

Beilstein J. Org. Chem. 2020, 16, 2960–2970, doi:10.3762/bjoc.16.246

• dichloromethane/hexane mixture. The structural data are given in Supporting Information File 1 (Tables S1–S3) and the molecular structure in the crystal of Me is shown in Figure 1. The Me derivative is not planar, as it adopts an asymmetrically twisted conformation. The dihedral angles (φ) between the two tolyl

• planes and the naphthalonitrile plane are 134.50° (C(3)–C(2)–C(12)–C(17)) and 46.80° (C(6)–C(1)–C(19)–C(24)), respectively. This means that the molecular structure of Me should involve torsion, which can be attributed to the steric hindrance of the two ortho-oriented phenyl rings. We can also observe

• applications or in the case of NMe2, as sensors of dielectric constants or water content. Molecular structure in the crystal of Me as obtained by X-ray diffractometric analysis. Thermal displacement ellipsoids are shown with 50% probability. Color code: black = carbon, grey = hydrogen and blue = nitrogen. A

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

• Emese Gal,
• Luiza Gaina,
• Hermina Petkes,
• Alexandra Pop,
• Castelia Cristea,
• Gabriel Barta,
• Dan Cristian Vodnar and
• Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

• Crystallographic Data Centre as supplementary publication (CCDC 2018198) (deposit@ccdc.cam.ac.uk). The molecular structure for the representative compound 2a is depicted in Figure 1. As revealed from the crystal packing structure shown in Figure 1, compound 2a forms a single crystalline phase containing both

• enantiomers of the chiral molecular structure in an ordered 1:1 ratio in the elementary cell. The phenothiazine unit shows a quasi-equatorial orientation of the methyl group attached to the heterocyclic nitrogen atom and a folding angle of 143.3°, a value close to the typical folding angle for unsubstituted

Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system

• David Liese,
• Hans Henning Wenk,
• Xin Lu,
• Jochen Kleinen and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2020, 16, 2820–2830, doi:10.3762/bjoc.16.232

• interaction of the alkyl chains. Keywords: dirhamnolipid ester; gemini surfactant; rheology; reverse wormlike micelle (RWLM); Introduction Surfactants have both hydrophilic and hydrophobic groups and are therefore amphiphilic molecules. Due to their unique molecular structure, surfactants are essential

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