Small anion-assisted electrochemical potential splitting in a new series of bistriarylamine derivatives: organic mixed valency across a urea bridge and zwitterionization

• Keishiro Tahara,
• Tetsufumi Nakakita,
• Alyona A. Starikova,
• Takashi Ikeda,
• Masaaki Abe and
• Jun-ichi Kikuchi

Beilstein J. Org. Chem. 2019, 15, 2277–2286, doi:10.3762/bjoc.15.220

• performed using the Gaussian09 software [63]. The three-parameterized Becke–Lee–Yang–Parr (B3LYP) hybrid exchange-correlation functional [64] was selected using the 6-31G(d) basis set for 1a and 1b with a restricted method and using the 6-311++G(d,p) basis set for the MV species with an unrestricted method

Aggregation-induced emission effect on turn-off fluorescent switching of a photochromic diarylethene

• Luna Kono,
• Yuma Nakagawa,
• Ayako Fujimoto,
• Ryo Nishimura,
• Yohei Hattori,
• Toshiki Mutai,
• Nobuhiro Yasuda,
• Kenichi Koizumi,
• Satoshi Yokojima,
• Shinichiro Nakamura and
• Kingo Uchida

Beilstein J. Org. Chem. 2019, 15, 2204–2212, doi:10.3762/bjoc.15.217

• subsequent TDDFT calculations. For the calculation of the fluorescence, the geometry optimizations were performed for the first excited state obtained by TDDFT. The hybrid B3LYP functional [33][34][35] was adopted to exchange-correlation term of DFT. The gaussian 6-31G(d,p) basis set was adopted to all

Azologization and repurposing of a hetero-stilbene-based kinase inhibitor: towards the design of photoswitchable sirtuin inhibitors

• Christoph W. Grathwol,
• Nathalie Wössner,
• Sören Swyter,
• Adam C. Smith,
• Enrico Tapavicza,
• Robert K. Hofstetter,
• Anja Bodtke,
• Manfred Jung and
• Andreas Link

Beilstein J. Org. Chem. 2019, 15, 2170–2183, doi:10.3762/bjoc.15.214

• SV(P) basis set [68][69]. The 10 lowest excitation energies and their oscillator strengths were computed using the SV(P) basis and the larger def2-TZVP basis set [69]. This was done using TDDFT with the hybrid approximation to the XC functional PBE0, CC2, and ADC(2) [51][52][53][70][71][72]. ADC(2

Fluorinated azobenzenes as supramolecular halogen-bonding building blocks

• Esther Nieland,
• Oliver Weingart and
• Bernd M. Schmidt

Beilstein J. Org. Chem. 2019, 15, 2013–2019, doi:10.3762/bjoc.15.197

• help of quantum mechanical calculations involving a combination of low-cost implicit solvation models and hybrid density functionals when including dispersion corrections. Electrostatic potential map at different isodensity values (B3LYP/ def2/TZVP/DGZVP optimized geometries) with a) ρ = 0.0001, and b

Tautomerism as primary signaling mechanism in metal sensing: the case of amide group

• Vera Deneva,
• Georgi Dobrikov,
• Aurelien Crochet,
• Daniela Nedeltcheva,
• Katharina M. Fromm and
• Liudmil Antonov

Beilstein J. Org. Chem. 2019, 15, 1898–1906, doi:10.3762/bjoc.15.185

• still not appear even after 1024 scans. Theoretical calculations Quantum-chemical calculations were performed using the Gaussian 09 D.01 program suite [17]. The M06-2X functional [18][19] was used with the 6-31++G** basis set for the calculations. This fitted hybrid meta-GGA functional with 54% HF

Identification of optimal fluorescent probes for G-quadruplex nucleic acids through systematic exploration of mono- and distyryl dye libraries

• Xiao Xie,
• Michela Zuffo,
• Marie-Paule Teulade-Fichou and
• Anton Granzhan

Beilstein J. Org. Chem. 2019, 15, 1872–1889, doi:10.3762/bjoc.15.183

• and RNA structures The fluorimetric response of the dye library was investigated against a set of 14 diverse nucleic acid structures (Table 2), including ten G4-DNA structures of different topologies (parallel G4: c-kit2, 25CEB, c-kit87up, c-myc, c-src1; parallel dimer G4: c-myb; hybrid G4: 22AG, 46AG

• towards hybrid (22AG, 46AG) and antiparallel (HRAS) G4-DNA, whereas the second group (dyes 1s, 1u, 1v, 17a and 18a) shows fluorimetric selectivity for parallel G4-DNA forms (c-kit2, c-kit87up, c-myc). To verify the preferences of the dyes with respect to the conformation of the G4 analytes, we analysed

• this plot, PC1 (x axis) correlates with the overall light-up intensity observed for each dye with the tested targets. On the contrary, PC2 (y axis) correlates with the intra-G4 selectivity of each compound, with compounds selective for hybrid and antiparallel G4s locating in the lower part of the plot

Halide metathesis in overdrive: mechanochemical synthesis of a heterometallic group 1 allyl complex

• Ross F. Koby,
• Nicholas R. Rightmire,
• Nathan D. Schley,
• Timothy P. Hanusa and
• William W. Brennessel

Beilstein J. Org. Chem. 2019, 15, 1856–1863, doi:10.3762/bjoc.15.181

• this and several related points more quantitatively, various features of the K/Cs/[allyl]− system were modeled with DFT calculations, using the B3PW91 hybrid functional [27][28] with Grimme’s -D3 dispersion corrections (GD3BJ) [29]. A calculation on the simple model systems [K(C3H5)] and [Cs(C3H5

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• organic counterpart, i.e., bulk heterojunction solar cells, or other hybrid PV technologies such as perovskite solar cells. DSSCs can display satisfactory power conversion efficiencies (PCE) in the range of 10 to 14% [1][2][3] but also a long-term stability when specific electrolytes based on ionic

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

• Maximilian Niehues,
• Patricia Tegeder and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2019, 15, 1407–1415, doi:10.3762/bjoc.15.140

• –organic hybrid nanomaterials. Keywords: cyclodextrins; gold nanorods; host–guest chemistry; light-responsive materials; molecular switches; self-assembly; Introduction Metallic nanomaterials have received intense and interdisciplinary interest due to their unique optical [1], electronic [2][3] and

• linker molecule (dAAP) led to light-responsive reversible self-assembly of AuNR in an end-to-end manner as depicted in Scheme 1 to open up a novel strategy for the design of hybrid nanomaterials by supramolecular chemistry. Results and Discussion The AuNR (length: 58 nm, width: 25 nm, aspect-ratio: 2.3

• successful method for the fabrication of new hybrid nanomaterials by the application of light-responsive host–guest chemistry allowing for effective control over assembled and disassembled states of anisotropic nanoparticles over several cycles. Experimental Instrumentation and materials All chemicals were

Bambusuril analogs based on alternating glycoluril and xylylene units

• Tomáš Lízal and
• Vladimír Šindelář

Beilstein J. Org. Chem. 2019, 15, 1268–1274, doi:10.3762/bjoc.15.124

• which can interact with cationic, anionic or neutral guest molecules. Here we present the design and synthesis of a new hybrid macrocycle containing glycoluril and aromatic units. The reaction afforded a mixture of macrocyclic homologues from which a two-membered macrocycle was isolated as the main

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• displaying biological activities such as antimicrobial, antiviral and anti-inflammatory, among others. Scheme 3 exemplifies the reaction of cholestan-6-one 7 with 2-aminopyridine and phenyl isocyanide to afford the heterocycle–steroid hybrid 8 in good yield and diastereoselectivity, whereas different

• paraformaldehyde and benzyl isocyanide to form hybrid 11 in good yield. Similarly, the spirostanic lactone 12 was transformed into spirostanic acid 13 and amine 14, which were next ligated to alanine methyl ester and Boc-histidine leading to the amino acid–steroid conjugates 15 and 16, respectively. This approach

• bonds in one-pot, leading to a remarkably complex amino acid–steroid hybrid 27 in very good yield [29]. After the pioneering work of Wessjohann and co-workers, other groups relied on the functionalization of steroids with isocyanide groups for their subsequent derivatization by isocyanide-based MCRs

Mechanochemical synthesis of hyper-crosslinked polymers: influences on their pore structure and adsorption behaviour for organic vapors

• Sven Grätz,
• Sebastian Zink,
• Hanna Kraffczyk,
• Marcus Rose and
• Lars Borchardt

Beilstein J. Org. Chem. 2019, 15, 1154–1161, doi:10.3762/bjoc.15.112

• variety of these materials [1]. While inorganic materials such as activated carbons, porous metal oxides, and zeolites have been investigated for decades, hybrid materials such as metal-organic frameworks [2], purely organic frameworks such as crystalline covalent-organic frameworks [3], and amorphous

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• ]. Besides, several hybrid molecules containing, inter alia the oxindole moiety, have been discovered and they demonstrated diverse therapeutic activities, for example, against breast [46] and colon cancer cells [47] and drug-resistant bacteria [48]. Among the many excellent recent reviews on the preparation

Catalytic asymmetric oxo-Diels–Alder reactions with chiral atropisomeric biphenyl diols

• Chi-Tung Yeung,
• Wesley Ting Kwok Chan,
• Wai-Sum Lo,
• Ga-Lai Law and
• Wing-Tak Wong

Beilstein J. Org. Chem. 2019, 15, 955–962, doi:10.3762/bjoc.15.92

• supramolecular helices or dimers through intermolecular hydrogen bonding of two axially chiral biphenyl hybrid diols (1 and 2 in Scheme 1) which contain point chirality at the side arms and axial chirality at the biphenyl backbone [37]. We envisage the structural similarity and the ability of our scaffold to

• other biphenyl hybrid diols with different steric bulky substituents were incorporated (3 and 4). Since it is known that the catalyst acidity has significant influence on hydrogen-bond-catalyzed reactions [32], we also incorporated a CF3 group in our molecular scaffold to investigate how it would affect

Synthesis of (macro)heterocycles by consecutive/repetitive isocyanide-based multicomponent reactions

• Angélica de Fátima S. Barreto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2019, 15, 906–930, doi:10.3762/bjoc.15.88

• approach provided the synthesis of steroid-biaryl ether hybrid macrocycles 117 and 118 with up to 68 members by the MiBs strategy. Another representative example of MiBs is the synthesis of the biaryl ether-containing macrocycles 123a–f (Scheme 23) [39]. The synthetic strategy involved the mixing of three

• [41] performed the first use of the diamine/diacid combination of bidirectional Ugi-MiBs in the synthesis of novel steroid–peptoid hybrid macrocycles. Scheme 25 shows two examples using this combination for the synthesis of cholane–peptoid hybrid macrocycles. Another application of the MiBs approach

• -based macrocyclization yielded steroid-aryl hybrid macroheterocycles 151 and 152, which after ester hydrolysis, acted as trifunctional building blocks for consecutive 3-fold Ugi-4CR-based macrocyclizations with triisocyanide 153. The cross-linked igloo-shaped skeletons of cages 154 and 155 were obtained

Azologization of serotonin 5-HT₃ receptor antagonists

• Karin Rustler,
• Galyna Maleeva,
• Piotr Bregestovski and
• Burkhard König

Beilstein J. Org. Chem. 2019, 15, 780–788, doi:10.3762/bjoc.15.74

• hybrid biomolecule. In this context, various photochromic scaffolds including dithienylethenes, fulgi(mi)des, and azobenzenes are investigated [31][42]. The latter ones were already discovered in 1834 by E. Mitscherlich [43] but it took around another 100 years till G. S. Hartley [44] revealed their

Catalyst-free assembly of giant tris(heteroaryl)methanes: synthesis of novel pharmacophoric triads and model sterically crowded tris(heteroaryl/aryl)methyl cation salts

• Rodrigo Abonia,
• Luisa F. Gutiérrez,
• Braulio Insuasty,
• Jairo Quiroga,
• Kenneth K. Laali,
• Chunqing Zhao,
• Gabriela L. Borosky,
• Samantha M. Horwitz and
• Scott D. Bunge

Beilstein J. Org. Chem. 2019, 15, 642–654, doi:10.3762/bjoc.15.60

• a set of “privileged structural motifs” that are present in both synthetic and naturally occurring compounds of practical and biological interest [29][30][31][32][33][34][35][36]. Consequently, there have been many attempts to produce hybrid structures with interesting properties by combining two

Polyaminoazide mixtures for the synthesis of pH-responsive calixarene nanosponges

• Antonella Di Vincenzo,
• Antonio Palumbo Piccionello,
• Alberto Spinella,
• Delia Chillura Martino,
• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2019, 15, 633–641, doi:10.3762/bjoc.15.59

• -sensitive functionalities in the highly hydrophobic nanoporous environment provided by the fully synthetic calixarene-based polymer, might open interesting perspectives for applicative purposes, in particular in the fields of organocatalysis and of hybrid organic-inorganic materials, such as in the emerging

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• , steepest descent algorithm) and systematic conformational analysis as implemented in Avogadro 1.1.1 software. The minimum energy conformers found by molecular mechanics were further optimized with the Gaussian 09 program package [57] by the means of DFT using B3LYP exchange–correlation hybrid functional

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• shock protein from M. Jannaschii (MjHSP) [71]. The authors reported a HG-II-type catalyst modified on its NHC backbone with an α-bromoacetyl unit (68) that is reacted with the unique cysteine of the modified MjHSP variant (G41C) to afford ArM 4 (Scheme 15). The hybrid catalyst ArM 4 was then tested for

• (NB4exp). The coupling reaction in aqueous buffer at pH 7.5 finally affords ArM 5, ArM 6 and ArM 7, respectively (Scheme 16). The obtained hybrid catalysts were tested for the RCM with substrates 21 and 64 (Table 9). Overall, ArM 6 and ArM 7 are comparable and perform best in both reactions with 35

• % conversion of substrate 21 and quantitative conversion of substrate 64. The water-soluble catalyst 9 was compared to the hybrid catalysts, displaying a higher TON in the RCM of 21 (Table 9, entry 4). Interestingly, the activity of catalyst 9 is inhibited in the presence of NB4exp (Table 9, entries 5 and 10

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• edges, chemically bonded with eight different or similar organic substituents so that it represents a truly hybrid architecture. The cubic silsesquioxane unit is characterized by a three-dimensional nanoscopic size structure with approximate Si–Si distance equal to 0.5 nm and an approximate R–R distance

• to 11033 Da and polydispersity index (PDI) = 1.5. Ring-opening metathesis polymerization (ROMP) of POSS-functionalized monomers The chemistry of inorganic–organic hybrid materials has emerged as a fascinating new field of modern nanotechnology. The inclusion of POSS cages into the polymeric material

• are the subject of numerous reviews [30][31][32][33][34][35][36][37]. From among the methods for preparation of organic–inorganic hybrid materials, polymerization or copolymerization is particularly convenient to incorporate POSS units into polyolefins. Ring-opening metathesis polymerization (ROMP) is

Adhesion, forces and the stability of interfaces

• Robin Guttmann,
• Johannes Hoja,
• Christoph Lechner,
• Reinhard J. Maurer and
• Alexander F. Sax

Beilstein J. Org. Chem. 2019, 15, 106–129, doi:10.3762/bjoc.15.12

Fabrication of supramolecular cyclodextrin–fullerene nonwovens by electrospinning

• Hiroaki Yoshida,
• Ken Kikuta and
• Toshiyuki Kida

Beilstein J. Org. Chem. 2019, 15, 89–95, doi:10.3762/bjoc.15.10

• , 380, and 475 nm) are observed. These results clearly suggest the successful preparation of β-CD (γ-CD) fiber materials with molecularly dispersed C60 (C70). The preparation of hybrid materials of a polymer and a CD–fullerene inclusion complex might be interesting to enhance material integrity and

Synthesis, biophysical properties, and RNase H activity of 6’-difluoro[4.3.0]bicyclo-DNA

• Sibylle Frei,
• Adam K. Katolik and
• Christian J. Leumann

Beilstein J. Org. Chem. 2019, 15, 79–88, doi:10.3762/bjoc.15.9

• oligonucleotides hybridized to complementary DNA or RNA disclosed a significant destabilization of both duplex types (ΔTm/mod = −1.6 to −5.5 °C). However, in the DNA/RNA hybrid the amount of destabilization could be reduced by multiple insertions of the modified unit. In addition, CD spectroscopy of the

• cleavage of the RNA strand of an AON/RNA hybrid structure by the endonuclease RNase H [9][18]. Both, the F–ANA and the F–RNA, are appealing modifications for several oligonucleotide-based silencing applications [8][19][20][21][22][23][24][25]. Also evaluated on their antisense properties were the 3

• (ΔTm/mod = −5.4 °C and −4.5 °C for complementary DNA and RNA, respectively). Interestingly, the DNA/RNA hybrid structure better accommodated multiple 6’-diF-bc4,3-Ts than a single insertion. Additionally, the hybrid structure also better tolerated multiple 6’-diF-bc4,3-T units than the DNA/DNA duplex