Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

• Lukáš Ďurina,
• Anna Ďurinová,
• František Trejtnar,
• Ľuboš Janotka,
• Lucia Messingerová,
• Jana Doháňošová,
• Ján Moncol and
• Róbert Fischer

Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188

• tubular cells HK2. (−)-Codonopsinol B (1) and its N-nor-methyl analogue 2; known inhibition activities against α-glucosidases from: (a) Bacillus stearothermophilus lyoph., (b) yeast [2]. Molecular structure of N-Cbz-protected pyrrolidine 12 confirmed by single-crystal X-ray crystallographic analysis

Synthesis of new pyrazolo[1,2,3]triazines by cyclative cleavage of pyrazolyltriazenes

• Nicolai Wippert,
• Martin Nieger,
• Claudine Herlan,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2021, 17, 2773–2780, doi:10.3762/bjoc.17.187

• able to exemplarily determine the molecular structure by X-ray crystallography, proving the regioisomer obtained in the alkylation reaction (Figure 2). While isomer 12 was used for the synthesis of pyrazolo[3,4-d][1,2,3]-3H-triazine derivatives of general structure 5, the isomer 13 was intended to

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

• Dušan Đ. Škorić,
• Olivera R. Klisurić,
• Dimitar S. Jakimov,
• Marija N. Sakač and
• János J. Csanádi

Beilstein J. Org. Chem. 2021, 17, 2611–2620, doi:10.3762/bjoc.17.174

• the aromatic tetrazole ring. A characteristic example of this is the H-17 proton in compound 13 with an unusually high chemical shift (2.85 ppm). Unambiguous confirmation of the tetrazole molecular structure came from the XRD analysis of compounds 13 and 14 (Figure 3) [50][51]. The already established

• , TMSOTf proved to be the most efficient. High yields of the desired tetrazole compounds with no lactam byproduct were obtained. The molecular structure and stereochemistry of newly synthesized tetrazoles was established by detailed NMR analysis. For compounds 13 and 14, the structure was established by

In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• synthesized utilizing a polycondensation of a perylene tetracarboxylic dianhydride with polyether-based diamines and the resulting materials were investigated using various analytical techniques. Thus, the molecular structure of the polymers could be correlated with the ability for self-healing. Moreover, the

• is evident that the broadening of the band shows an intensive increase at 150 °C. This nonlinear behavior indicates a drastic change in molecular structure around this temperature range, which corresponds to the observed signals in the DSC measurements and the findings of the DMTA analysis. The

• , which correlates to the changes of the molecular structure. Furthermore, the scratch healing was analyzed in detail showing that only one of the two polymers studied, polymer P1 is able to heal scratches in a sufficient manner at temperature higher than the activation of the π–π interaction. In contrast

(Phenylamino)pyrimidine-1,2,3-triazole derivatives as analogs of imatinib: searching for novel compounds against chronic myeloid leukemia

• Luiz Claudio Ferreira Pimentel,
• Lucas Villas Boas Hoelz,
• Henayle Fernandes Canzian,
• Frederico Silva Castelo Branco,
• Andressa Paula de Oliveira,
• Vinicius Rangel Campos,
• Floriano Paes Silva Júnior,
• Rafael Ferreira Dantas,
• Jackson Antônio Lamounier Camargos Resende,
• Anna Claudia Cunha,
• Nubia Boechat and
• Mônica Macedo Bastos

Beilstein J. Org. Chem. 2021, 17, 2260–2269, doi:10.3762/bjoc.17.144

• analysis, the molecular structure was confirmed, as shown in Figure 2. Biological assay The compounds showed significant inhibitory activity at 10 μM but not at 1 μM (Figure 3). Compounds 2c, 2d, and 2g were the most promising, and concentration–response curves were drawn to determine the cytotoxic

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

• the design of novel thermoresponsive polymers exhibiting UCST type behavior. Seuring et al. [51][54], Niskanen et al. [50], Bansal et al. [52] or Zhao et al. [55] summarize known thermoresponsive building blocks based on their molecular structure and offer interesting design approaches supported by

• published studies, the present review does not only focus on the molecular structure of thermoresponsive polymers and their synthesis but also discusses their phase transitions, in terms of structure–property relationships arising from the alignment of the polymer chains in assemblies of constrained

Free-radical cyclization approach to polyheterocycles containing pyrrole and pyridine rings

• Ivan P. Mosiagin,
• Olesya A. Tomashenko,
• Dar’ya V. Spiridonova,
• Mikhail S. Novikov,
• Sergey P. Tunik and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2021, 17, 1490–1498, doi:10.3762/bjoc.17.105

• ]isoquinoline backbone from N-unprotected pyrrolylpyridinium salts and, unlike the Pd-catalyzed version cyclization, avoids the deprotection step that is accompanied by isomerization. Molecular structure of compound 3a, displacement parameters are drawn at 50%. Molecular structure of compound 13, displacement

• parameters are drawn at 50% probability level. Molecular structure of compound 17a, displacement parameters are drawn at 50% probability level. Retrosynthetic analysis of heterocycles A and B. Free-radical cyclization of N-protected and N-unprotected pyrroles 1a and 2. Synthesis of 2H-pyrido[2,1-a]pyrrolo

Effective microwave-assisted approach to 1,2,3-triazolobenzodiazepinones via tandem Ugi reaction/catalyst-free intramolecular azide–alkyne cycloaddition

• Maryna O. Mazur,
• Oleksii S. Zhelavskyi,
• Eugene M. Zviagin,
• Svitlana V. Shishkina,
• Vladimir I. Musatov,
• Maksim A. Kolosov,
• Elena H. Shvets,
• Anna Yu. Andryushchenko and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2021, 17, 678–687, doi:10.3762/bjoc.17.57

• compounds was obtained. Currently, we are working on testing some library representatives for their biological activity. Benzodiazepine-based azolo-containing drugs. Novel potential 1,2,3-triazolobenziadiazepine drugs. Code legend for Ugi products 6 and molecular structure (X-ray analysis) of compound 6aaa

• . 1H NMR spectra of the reactant and the product of IAAC. Molecular structure of compound 7aaa (X-ray analysis) and comparison of 1H NMR spectra of compounds 6aaa and 7aaa. Examples of synthesis of 1,2,3-triazolobenzodiazepines via tandem approach Ugi reaction/IAAC. Reagents and conditions: (a) MeOH

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

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• ideal partner for drug lipophilization by conjugation [37]. Highly efficient fullerene conjugates with chemotherapeutic agents have been synthesized and patented; moreover, the biological activity profile is often preserved, but in some cases it can also change since a molecular structure with a

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