Shortcuts for Electron-Transfer through the Secondary Structure of Helical Oligo-1,2-Naphthylenes

Taking shortcuts: Phototriggered electron transfer between a triarylamine unit and a ruthenium complex follows shortcuts in the secondary structure of a naphthylene-based molecular bridge, leading to a particularly low distance dependence of reaction rates and overall faster electron transfer (see scheme).

[Full Papers]

Alessandro Castrogiovanni, Patrick Herr, Dr. Christopher B. Larsen, Dr. Xingwei Guo, Prof. Dr. Christof Sparr, Prof. Dr. Oliver S. Wenger

doi.org/10.1002/chem.201904771

Sampling Potential Energy Surfaces in the Condensed Phase with Many-Body Electronic Structure Methods

Many-body electronic structure methods have been practically unavailable for sampling PES in the condensed-phase. This has changed during the last few years, as efficient algorithms and software implementations for the evaluation of electronic energies and forces on atoms have been developed. Herein, the theory and software developments and an overview the applications in the field are introduced with the most encouraging results being obtained for aqueous chemistry (see figure).

[Minireviews]

Dr. Vladimir V. Rybkin

doi.org/10.1002/chem.201904012

Expanding the Scope of Water-Stable Rhenium(V)-NHC Complexes - Synthesis, Characterization, and Derivatization

The synthesis of novel ReV complexes bearing a tridentate NHC scorpionate ligand is reported. The complexes were fully characterized, including X-ray structural analyses. Additionally, their stability towards air and moisture was investigated. The new ReV NHC scorpionate motif discussed herein is one step further in the direction towards water-stable Re-based metallodrugs.

[Communications]

Dustin Bornemann, Lukas Schlemper, Nils Trapp, Antonio Togni

doi.org/10.1002/ejic.201901077

Decomposition of Picolyl Radicals at High Temperature: A Mass Selective Threshold Photoelectron Spectroscopy Study

The picolyl radical is a crucial intermediate in reactive environments, for example, the combustion of biofuels. Its unimolecular dissociation products at high temperature were characterized by mass-selective threshold photoelectron spectroscopy and several hitherto unexplored reactive molecules were characterized.

[Full Papers]

Engelbert Reusch, Dr. Fabian Holzmeier, Marius Gerlach, Prof. Dr. Ingo Fischer, Dr. Patrick Hemberger

doi.org/10.1002/chem.201903937

Fused N-Heterocycles with Contiguous Stereogenic Centers Accessed by an Asymmetric Catalytic Cascade Reaction of Tertiary Enamides

A domino game: Under treatment of a chiral binol-Ti complex and BF3, cyclopentanone-derived tertiary enamides undergo the enantioselective enamine addition to ketone carbonyls followed by diastereoselective trapping of the resulting acyliminiums by electron-rich aryl moieties to furnish ring-fused N-heterocyclic products in high yields and excellent enantioselectivities.

[Communications]

Li Zhen, Prof. Shuo Tong, Prof. Jieping Zhu, Prof. Mei-Xiang Wang

doi.org/10.1002/chem.201904596

Scalable Multicomponent Synthesis of (Hetero)aryl-Substituted Phenyls: Focus on Metal-Free Halogenated Biaryls, 3-Arylindoles, and Isourolithine A Synthesis

A simple, scalable and metal-free multicomponent enol acetylation of (hetero)arylidene acetones followed by a thermal Diels-Alder reaction with methyl propiolate was accomplished in a pressure metal vessel. Aromatization of the cycloadduct intermediates yielded the corresponding functionalised (hetero)biaryls.

[Full Papers]

Andrea Temperini, Daniela Lanari, Francesco Colognese, Francesca Piazzolla

doi.org/10.1002/ejoc.201901551

Piano Stool Aminoalkylidene-Ferracyclopentenone Complexes from Bimetallic Precursors: Synthesis and Cytotoxicity Data

Amine-promoted selective fragmentation of readily available diiron vinyliminium complexes can be broadly applied to the synthesis of piano-stool monoiron products featuring a unique structural motif, which is partially constructed by exploiting Fe−Fe cooperativity. The compounds display a variable cytotoxicity against cancer (A2780 and A280cisR) and non-cancerous (HEK293) cell lines, and a significant selectivity has been observed with a phenyl ring as vinyl substituent.

[Full Papers]

Dalila Rocco, Dr. Lucinda K. Batchelor, Dr. Eleonora Ferretti, Prof. Stefano Zacchini, Prof. Guido Pampaloni, Prof. Paul J. Dyson, Prof. Fabio Marchetti

doi.org/10.1002/cplu.201900639

NMR Spectroscopic Characterization of Flame-Made Amorphous Silica-Alumina for Cyclohexanol and Glyceraldehyde Conversion

Forged in fire: The Flame-made amorphous silica-aluminas (ASAs) exhibited excellent catalytic performance for the dehydration of cyclohexane and the conversion of glyceraldehyde to ethyl lactate. The enhanced Brønsted acidity promotes the cyclohexane dehydration providing TOFs up to 7 times higher than those obtained with their co-condensed counterparts and 20 times higher reaction rates based on unit surface area (mol m−2 s−1) than those prepared by ALD and CLD.

[Full Papers]

Dr. Zichun Wang, Dr. Yijiao Jiang, Prof. Catherine Stampfl, Prof. Alfons Baiker, Prof. Michael Hunger, Prof. Jun Huang

doi.org/10.1002/cctc.201901728

The [4+2]-Cycloaddition of α-Nitrosoalkenes with Thiochalcones as a Prototype of Periselective Hetero-Diels-Alder Reactions—Experimental and Computational Studies

Superdienophiles select one of eight conceivable pathways! The hetero-Diels-Alder reactions of α-nitrosoalkenes with thiochalcones are highly periselective and regioselective processes, providing only one of eight possible constitutional isomers. The thiochalcones undergo a regioselective, but reversible dimerization. High-level DFT calculations reveal that these processes are kinetically controlled.

[Full Papers]

Prof. Grzegorz Mlostoń, Dr. Katarzyna Urbaniak, Dr. Marcin Jasiński, Prof. Ernst-Ulrich Würthwein, Prof. Heinz Heimgartner, Dr. Reinhold Zimmer, Prof. Hans-Ulrich Reissig

doi.org/10.1002/chem.201903385

Photochemical Reactions in the Synthesis of Protein-Drug Conjugates

Rapid and efficient protein functionalisation: Photochemistry harbours a wealth of exciting reagents and reactions that represent an untapped resource for applications in protein modification. This Concept article introduces the key ideas that underpin photoradiosynthesis and surveys the chemical scope and associated mechanistic attributes of different photochemical processes that hold promise for future synthesis of antibody-drug conjugates, radiopharmaceuticals, and fluorescent proteins.

[Concepts]

Jason P. Holland, Melanie Gut, Simon Klingler, Rachael Fay, Amaury Guillou

doi.org/10.1002/chem.201904059

Self-Assembly of Proteinaceous Shells around Positively Charged Gold Nanomaterials Enhances Colloidal Stability in High-Ionic-Strength Buffers

Engineered electrostatic interactions enable the self-assembly of a lumazine synthase variant on differently sized and shaped gold nanomaterials. The resulting complexes possess dramatically enhanced colloidal stability in high-ionic-strength buffers owing to the formation of a protective ≈4-nm-thick proteinaceous shell around the core particle.

[Communications]

Dr. Eita Sasaki, Ryan M. Dragoman, Dr. Shiksha Mantri, Dr. Dmitry N. Dirin, Prof. Dr. Maksym V. Kovalenko, Prof. Dr. Donald Hilvert

doi.org/10.1002/cbic.201900469

Carbon-Nanotube-Supported Copper Polyphthalocyanine for Efficient and Selective Electrocatalytic CO2 Reduction to CO

Transient restructuring: A copper polyphthalocyanine/carbon nanotubes hybrid catalyst exhibits high selectivity for electroreduction of CO2 to CO. Operando X-ray absorption spectroscopy shows reversible restructuring of the catalyst surface during electrolysis. At cathodic potentials, transient small Cu nanoparticles are formed and are likely the catalytically active species. The initial material with isolated Cu sites is recovered at anodic potentials.

[Full Papers]

Dilan Karapinar, Andrea Zitolo, Tran Ngoc Huan, Sandrine Zanna, Dario Taverna, Luiz Henrique Galvão Tizei, Domitille Giaume, Philippe Marcus, Victor Mougel, Marc Fontecave

doi.org/10.1002/cssc.201902859

Identification of Synthetic Activators of Cancer Cell Migration by Hybrid Deep Learning

Reading the images: Neural networks are explored for their utility in the drug discovery process. In this study a convolutional neural network was trained using self-organizing maps of molecular pharmacophores. The trained network identified chemokine receptor ligands which were tested in a functional assay and then confirmed in a three-dimensional spheroid invasion assay.

[Full Papers]

Dominique Bruns, Erik Gawehn, Dr. Karthiga Santhana Kumar, Dr. Petra Schneider, Dr. Martin Baumgartner, Prof. Dr. Gisbert Schneider

doi.org/10.1002/cbic.201900346

Structure−Activity Relationships of Cinnamate Ester Analogues as Potent Antiprotozoal Agents

Fighting parasitic diseases: A classical phenotypic approach combined with a comprehensive SAR study led to establishment of potent and selective cinnamate ester analogues acting in vitro against Leishmania donovani and Trypanosoma brucei rhodesiense. Key structural requirements for activity were determined resulting in interesting candidates for further development.

[Full Papers]

Freddy A. Bernal, Dr. Marcel Kaiser, Prof. Dr. Bernhard Wünsch, Prof. Dr. Thomas J. Schmidt

doi.org/10.1002/cmdc.201900544

Methyl Scanning for Mechanochemical Chalcogen-Bonding Cascade Switches

Not every atom matters: Chemistry tools made for the fluorescent imaging of physical forces in biological systems subjected to single methyl group deletions: Whereas methyl groups in the twisting region are essential, the pink methyl in the switching region does not interfere with function, a result that required significant multistep organic synthesis to obtain and will therefore be thoroughly appreciated in future probe design.

[Communications]

Dr. Xiang Zhang, Dr. Naomi Sakai, Prof. Stefan Matile

doi.org/10.1002/open.201900288

A Convenient Synthesis of Difluoroalkyl Ethers from Thionoesters Using Silver(I) Fluoride

Mild at heart: A new method for the synthesis of difluoroalkyl ethers that involves the direct fluorodesulfurization of thionoesters with AgF at room temperature is reported (see scheme). This method should enable the synthesis of a wide range of difluoroalkyl ethers with applications in medicinal and materials chemistry, and radiotracer production.

[Communications]

Josiah Newton, Daniel Driedger, Dr. Matthew B. Nodwell, Dr. Paul Schaffer, Dr. Rainer E. Martin, Prof. Dr. Robert Britton, Prof. Dr. Chadron M. Friesen

doi.org/10.1002/chem.201904132

Small and Narrowly Distributed Copper Nanoparticles Supported on Carbon Prepared by Surface Organometallic Chemistry for Selective Hydrogenation and CO2 Electroconversion Processes

Supported Catalyst: Carbon-supported copper nanoparticles prepared via surface organometallic chemistry are active catalysts in selective hydrogenation and CO2 electroconversion.

[Full Papers]

Dr. Christos K. Mavrokefalos, Dr. Nicolas Kaeffer, Dr. Hsueh-Ju Liu, Dr. Frank Krumeich, Prof. Christophe Copéret

doi.org/10.1002/cctc.201901414

Conjugating Biotin to Ruthenium(II) Arene Units via Phosphine Ligand Functionalization

Robust ruthenium(II) arene compounds incorporating biotin through a phosphine linkage were synthesized and assessed for their cytotoxicity against several cancer cell lines with different levels of biotin transporter expression, and for their apparent affinity to avidin.

[Full Papers]

Lorenzo Biancalana, Martyna Gruchała, Lucinda K. Batchelor, Andrzej Błauż, Andrea Monti, Guido Pampaloni, Błażej Rychlik, Paul J. Dyson, Fabio Marchetti

doi.org/10.1002/ejic.201900922

Modulation of Pharmacologically Relevant Properties of Piperidine Derivatives by Functional Groups in an Equatorial or Axial β-Position to the Amino Group

A set of amine basicity and lipophilicity data for β-substituted piperidine derivatives provide enhanced insight into the stereospecific modulation of pharmacologically relevant properties by small substituents and prototypic functional groups, establishing a valuable reference base for molecular design.

[Full Papers]

Dr. Patrick Schnider, Cosimo Dolente, Dr. Henri Stalder, Dr. Rainer E. Martin, Dr. Viktoria Reinmüller, Dr. Roman Marty, Dr. Caroline Wyss Gramberg, Björn Wagner, Dr. Holger Fischer, Dr. André M. Alker, Prof. (emer.) Dr. Klaus Müller

doi.org/10.1002/cbic.201900474

Synthesis and Characterization of an Epidermal Growth Factor Receptor-Selective RuII Polypyridyl-Nanobody Conjugate as a Photosensitizer for Photodynamic Therapy

Specificity comes to light: RuII polypyridyl complexes used in photodynamic therapy (PDT) can target DNA. However, because DNA is ubiquitous, the selectivity of such photosensitizers could be increased by linking them to a targeting vector. Herein we present the synthesis, characterization, and in-depth photophysical evaluation of a nanobody-containing RuII polypyridyl conjugate selective for the epidermal growth factor receptor (EGFR) in view of targeted PDT.

[Full Papers]

Johannes Karges, Marta Jakubaszek, Dr. Cristina Mari, Dr. Kristof Zarschler, Dr. Bruno Goud, Dr. Holger Stephan, Dr. Gilles Gasser

doi.org/10.1002/cbic.201900419

Characterization of an Orphan Type III Polyketide Synthase Conserved in Uncultivated “Entotheonella” Sponge Symbionts

Common ground: Few of the diverse biosynthetic gene clusters found in uncultivated “Entotheonella” sponge symbionts are shared between phylotypes, and all of these are functionally uncharacterized. Herein, the characterization of conserved type III polyketide synthase (PKS) CepA is reported and it is shown that it produces phenolic lipids.

[Full Papers]

Dr. Silke Reiter, Dr. Jackson K. B. Cahn, Vincent Wiebach, Dr. Reiko Ueoka, Prof. Dr. Jörn Piel

doi.org/10.1002/cbic.201900352

Molecular Engineering of Simple Metal-Free Organic Dyes Derived from Triphenylamine for Dye-Sensitized Solar Cell Applications

Collecting light indoors: Two metal-free organic sensitizers, L156 and L224, are synthesized and characterized experimentally and theoretically. These dyes contain a triphenylamine segment and 4-(benzo[c][1,2,5]thiadiazol-4-yl)benzoic acid as electron-rich and -deficient moieties, respectively. The influence of different parameters on dye-sensitized solar-cell device performance is reported.

[Full Papers]

Dr. Parnian Ferdowsi, Yasemin Saygili, Dr. Farzan Jazaeri, Dr. Tomas Edvinsson, Dr. Javad Mokhtari, Dr. Shaik M. Zakeeruddin, Dr. Yuhang Liu, Prof. Michael Grätzel, Prof. Anders Hagfeldt

doi.org/10.1002/cssc.201902245

Synthesis of DNA-Encoded Disulfide- and Thioether-Cyclized Peptides

DNA-encoded cyclic peptides: A strategy for the efficient chemical synthesis of cyclic peptide-DNA conjugates was established. The peptides contain a pair of cysteine residues and are cyclized through disulfide or thioether bond formation. Key for the peptide-DNA conjugate synthesis was the use of tertbutylthio-protected Fmoc-cysteine as building block.

[Full Papers]

Dr. Manh V. Pham, Dr. Milan Bergeron-Brlek, Prof. Christian Heinis

doi.org/10.1002/cbic.201900390

Probing for Thiol-Mediated Uptake into Bacteria

In or out? Cyclic oligochalcogenides (COCs), inhibit, rather than mediate, uptake into bacteria. This conclusion, resulting from the synthesis and evaluation of a series of COC-antibiotic conjugates, supports that COCs penetrate mammalian cells along nontrivial uptake pathways involving dynamic covalent exchange chemistry, mobility along disulfide tracks, and adaptive micellar pores.

[Communications]

Quentin Laurent, Dr. Mathéo Berthet, Dr. Yangyang Cheng, Dr. Naomi Sakai, Dr. Sofia Barluenga, Prof. Nicolas Winssinger, Prof. Stefan Matile

doi.org/10.1002/cbic.201900378

Nucleotide Binding Modes in a Motor Protein Revealed by 31P- and 1H-Detected MAS Solid-State NMR Spectroscopy

Protein-nucleotide contacts in a noncrystalline bacterial DnaB helicase sedimented in the NMR rotor were probed by 31P- and 1H-detected solid-state NMR spectroscopy. The sensitivity of 1H chemical shifts to hydrogen bonding was explored and used to identify residues involved in nucleotide coordination.

[Communications]

Dr. Thomas Wiegand, Maarten Schledorn, Alexander A. Malär, Riccardo Cadalbert, Alexander Däpp, Dr. Laurent Terradot, Prof. Dr. Beat H. Meier, Dr. Anja Böckmann

doi.org/10.1002/cbic.201900439

Reductive Amination and Enantioselective Amine Synthesis by Photoredox Catalysis

The recently discovered photochemical reductive amination and the enantioselective amine synthesis by combined photoredox/enzymatic catalysis is reviewed.

[Minireview]

Xingwei Guo, Yasunori Okamoto, Mirjam R. Schreier, Thomas R. Ward, Oliver S. Wenger

doi.org/10.1002/ejoc.201900777

Aerobic Oxidation of Methyl-substituted β-Carbolines Catalyzed by N-Hydroxyphthalimide and Metal Catalyst

Carboxylic functionalized β-carbolines have been synthesized in good to excellent yields and high selectivity by oxygen in the presence of NHPI and transition metal salt under mild conditions

[Communications]

Hongda Qiu, Weida Liang, Dr. Gongjun Zhang, Miaoman Lin, Wanmin Liu, Prof. Zhanghua Gao, Dr. Wenting Wei, Dr. Chunlan Tang, Dr. Haixiao Jin, Prof. Hongze Liang, Prof. Xiaojun Yan

doi.org/10.1002/slct.201803007

Copper Catalyzed Direct Synthesis of Nitriles from Acyl Azides

A novel and general protocol for the copper catalyzed reductive elimination of acyl azides to nitriles using triethoxysilane is reported. Various nitriles are obtained in moderate to excellent yields with good functional group tolerance and high chemoselectivity.

[Communications]

Prof. Yang Chen, Yu Liu, Xiao Zhang, Da Lu, Lixin Yang, Junfeng Deng, Prof. Shengqi Deng

doi.org/10.1002/slct.201802918

Betti Bases from 4-(3-Pyridazo)-1-naphthol: Synthesis, Coordination Behaviour and Unusual Substitution Reactions

Synthesis, characterization and complexation ability study of a series of Betti bases from 4-(3-pyridyl)azo-1-naphthol dye, possessing flexible methylene or more constrained aryl-methyne spaced NH-containing side-chains, is presented. An unexpected result with side-chain pyridyl group replacement was obtained and the product was analysed by XRD. A possible pathway was suggested and synthetically confirmed.

[Full Papers]

Prof. Dr. Vanya B. Kurteva, Dr. Lubomir A. Lubenov, Prof. Dr. Boris L. Shivachev, Prof. Dr. Rositsa P. Nikolova, Prof. Dr. Katharina M. Fromm

doi.org/10.1002/slct.201802745