The Journal of Organic Chemistry: Latest Articles (ACS Publications)
Authors: Makoto Sasaki, Kotaro Iwasaki, and Keisuke Arai
feedproxy.google.com/~r/acs/joceah/~3/osv7pbxkqHo/acs.joc.0c03031
The Journal of Organic Chemistry: Latest Articles (ACS Publications)
Authors: Makoto Sugimoto, Sayaka Nosho, Gen Hikosaka, Yasunao Hattori, Koji Umezawa, Atsushi Kawamura, and Hidefumi Makabe
feedproxy.google.com/~r/acs/joceah/~3/4kr9xUDTaes/acs.joc.0c02831
The Journal of Organic Chemistry: Latest Articles (ACS Publications)
Authors: Xuedan Wu, Julia Marks, Chao Wang, Diane Dickie, and Lin Pu
feedproxy.google.com/~r/acs/joceah/~3/d3pKWEUtou4/acs.joc.1c00029
Authors: Biyue Lin, Jingping Kou, Shuming Wu, Xuerong Cai, Qingbo Xiao, Yinglong Li, Jian Hu, Jianbing Li, and Zhongqing Wang
feedproxy.google.com/~r/acs/oprdfk/~3/72VZTbA-cP0/acs.oprd.1c00004
Organic Letters: Latest Articles (ACS Publications)
Authors: Feng Chen, Xiu-Hua Xu, and Feng-Ling Qing
feedproxy.google.com/~r/acs/orlef7/~3/fCqNCYZTeGU/acs.orglett.1c00639
Organic Letters: Latest Articles (ACS Publications)
Authors: Tiffany Piou, Yuriy Slutskyy, Nancy J. Kevin, Zhongxiang Sun, Dong Xiao, and Jongrock Kong
feedproxy.google.com/~r/acs/orlef7/~3/HW6hJhDReqc/acs.orglett.1c00100
The Journal of Organic Chemistry: Latest Articles (ACS Publications)
Authors: Nuan Chen, Ting Zhou, Hong Zhang, Yuqi Zhu, Ming Lang, Jian Wang, and Shiyong Peng
feedproxy.google.com/~r/acs/joceah/~3/FLlJdPik-yU/acs.joc.1c00104
Journal of the American Chemical Society: Latest Articles (ACS Publications)
Authors: Philip R. D. Murray, Willem M. M. Bussink, Geraint H. M. Davies, Farid W. van der Mei, Alyssa H. Antropow, Jacob T. Edwards, Laura Akullian D’Agostino, J. Michael Ellis, Lawrence G. Hamann, Fedor Romanov-Michailidis, and Robert R. Knowles
feedproxy.google.com/~r/acs/jacsat/~3/VPst49ghgf4/jacs.1c01173
ACS Medicinal Chemistry Letters: Latest Articles (ACS Publications)
Authors: Sicheng Zhang, Luis O. Romero, Shanshan Deng, Jiaxing Wang, Yong Li, Lei Yang, David J. Hamilton, Duane D. Miller, Francesca-Fang Liao, Julio F. Cordero-Morales, Zhongzhi Wu, and Wei Li
feedproxy.google.com/~r/acs/amclct/~3/ZbVC7_JpBws/acsmedchemlett.0c00571
Journal of Medicinal Chemistry: Latest Articles (ACS Publications)
Authors: Tanja C. Knaab, Jana Held, Bjoern B. Burckhardt, Kelly Rubiano, John Okombo, Tomas Yeo, Sachel Mok, Anne-Catrin Uhlemann, Beate Lungerich, Christoph Fischli, Lais Pessanha de Carvalho, Benjamin Mordmüller, Sergio Wittlin, David A. Fidock, and Thomas Kurz
feedproxy.google.com/~r/acs/jmcmar/~3/PtluGU4mdsI/acs.jmedchem.0c01744
Journal of Medicinal Chemistry: Latest Articles (ACS Publications)
Authors: Ruiqin Ye, Lifang Sun, Jinghui Peng, Aixin Wu, Xiaozhu Chen, Lu Wen, Chuan Bai, and Gang Chen
feedproxy.google.com/~r/acs/jmcmar/~3/AVDemcNQ5eQ/acs.jmedchem.0c01916
Journal of the American Chemical Society: Latest Articles (ACS Publications)
Authors: Yi-Xiang Shi, Yue Wu, Shu-Qi Wang, Yang-Yong Zhao, Tie Li, Xian-Qing Yang, and Ting Zhang
feedproxy.google.com/~r/acs/jacsat/~3/AH3HIv6GUuM/jacs.1c00666
Journal of the American Chemical Society: Latest Articles (ACS Publications)
Authors: Suhyeon Kim, Dongwook Kim, Seung Youn Hong, and Sukbok Chang
feedproxy.google.com/~r/acs/jacsat/~3/S0boj1CLr-U/jacs.1c00652
Targeting actin requires spatiotemporal control of drug activity. Optojasps are photo‐switchable small molecules, providing direct optical spatiotemporal control of the actin cytoskeleton. We present high‐resolution cryo‐EM structures of both isomeric states of an optojasp bound to F‐actin and describe in detail the binding pocket and conformational changes associated with switching of the azobenzene.
Actin is essential for key processes in all eukaryotic cells. Cellpermeable optojasps provide spatiotemporal control of the actin cytoskeleton, confining toxicity and potentially rendering F‐actin druggable by photopharmacology. Here, we report cryo electron microscopy (cryo‐EM) structures of both isomeric states of one optojasp bound to actin filaments. The high‐resolution structures reveal for the first time the pronounced effects of photoswitching a functionalized azobenzene. By characterizing the optojasp binding site and identifying conformational changes within F‐actin that depend on the optojasp isomeric state, we refine determinants for the design of functional F‐actin photoswitches.
Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Sabrina Pospich, Florian Küllmer, Veselin Nasufović, Johanna Funk, Alexander Belyy, Peter Bieling, Hans‐Dieter Arndt, Stefan Raunser
doi.org/10.1002/anie.202013193
Privileged! Aromatic oligoamides based on pyrroles, pyridines, and p‐aminobenzoic acids are presented as privileged structures that efficiently target nucleic acids and proteins as well as complexes derived therefrom. Their design can be related to natural products such distamycin A and the cystobactamids.
The term “privileged structure” refers to a single molecular substructure or scaffold that can serve as a starting point for high‐affinity ligands for more than one receptor type. In this report, a hitherto overlooked group of privileged substructures is addressed, namely aromatic oligoamides, for which there are natural models in the form of cystobactamids, albicidin, distamycin A, netropsin, and others. The aromatic and heteroaromatic core, together with a flexible selection of substituents, form conformationally well‐defined scaffolds capable of specifically binding to conformationally well‐defined regions of biomacromolecules such as helices in proteins or DNA often by acting as helices mimics themselves. As such, these aromatic oligoamides have already been employed to inhibit protein–protein and nucleic acid–protein interactions. This article is the first to bring together the scattered knowledge about aromatic oligoamides in connection with biomedical applications.
Wiley: Chemistry – A European Journal: Table of Contents
Authors: Tim Seedorf, Andreas Kirschning, Danny Solga
chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.202005086
Existing methods for the chlorination of C(sp3)−H bonds occur with low site‐selectivity and tolerance for functional groups. We report a highly selective chlorination of C(sp3)−H bonds suitable for the late‐stage functionalization of natural products and active pharmaceutical ingredients by a reaction design that separates the components abstracting the H‐atom (an azidoiodinane) and transferring the chlorine atom (a copper(II) chloride complex).
C(sp3)−Cl bonds are present in numerous biologically active small molecules, and an ideal route for their preparation is by the chlorination of a C(sp3)−H bond. However, most current methods for the chlorination of C(sp3)−H bonds are insufficiently site selective and tolerant of functional groups to be applicable to the late‐stage functionalization of complex molecules. We report a method for the highly selective chlorination of tertiary and benzylic C(sp3)−H bonds to produce the corresponding chlorides, generally in high yields. The reaction occurs with a mixture of an azidoiodinane, which generates a selective H‐atom abstractor under mild conditions, and a readily‐accessible and inexpensive copper(II) chloride complex, which efficiently transfers a chlorine atom. The reaction’s exceptional functional group tolerance is demonstrated by the chlorination of >30 diversely functionalized substrates and the late‐stage chlorination of a dozen derivatives of natural products and active pharmaceutical ingredients.
Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Alexander Fawcett, M. Josephine Keller, Zachary Herrera, John F. Hartwig
doi.org/10.1002/anie.202016548
SAC reactivity from theory: A periodic conceptual DFT investigation elucidating the nature of the adsorption and catalytic activity of single silica‐supported late transition metal atoms was undertaken revealing the evidence of a strong correlation with experimental data and chemical properties.
The drive to develop maximal atom‐efficient catalysts coupled to the continuous striving for more sustainable reactions has led to an ever‐increasing interest in single‐atom catalysis. Based on a periodic conceptual density functional theory (cDFT) approach, fundamental insights into the reactivity and adsorption of single late transition metal atoms supported on a fully hydroxylated amorphous silica surface have been acquired. In particular, this investigation revealed that the influence of van der Waals dispersion forces is especially significant for a silver (98 %) or gold (78 %) atom, whereas the oxophilicity of the Group 8–10 transition metals plays a major role in the interaction strength of these atoms on the irreducible SiO2 support. The adsorption energies for the less‐electronegative row 4 elements (Fe, Co, Ni) ranged from −1.40 to −1.92 eV, whereas for the heavier row 5 and 6 metals, with the exception of Pd, these values are between −2.20 and −2.92 eV. The deviating behavior of Pd can be attributed to a fully filled d‐shell and, hence, the absence of the hybridization effects. Through a systematic analysis of cDFT descriptors determined by using three different theoretical schemes, the Fermi weighted density of states approach was identified as the most suitable for describing the reactivity of the studied systems. The main advantage of this scheme is the fact that it is not influenced by fictitious Coulomb interactions between successive, charged reciprocal cells. Moreover, the contribution of the energy levels to the reactivity is simultaneously scaled based on their position relative to the Fermi level. Finally, the obtained Fermi weighted density of states reactivity trends show a good agreement with the chemical characteristics of the investigated metal atoms as well as the experimental data.
Wiley: Chemistry – A European Journal: Table of Contents
Authors: Xavier Deraet, Jan Turek, Mercedes Alonso, Frederik Tielens, Stefaan Cottenier, Paul W. Ayers, Bert M. Weckhuysen, Frank De Proft
chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.202004660
A chiral spiro‐axis skeleton introduced the circularly polarized luminescence property into TADF molecules and enhanced the intramolecular through space charge transfer process. The resulting TADF enantiomers display obvious CPEL signals with |gEL| factor up to 3.0×10−3 and EQE of 20.0 % with remarkably low efficiency roll‐off, which are among the top results of CP‐OLEDs.
A spiro‐axis skeleton not only introduces circularly polarized luminescence (CPL) into thermally activated delayed fluorescence (TADF) molecules but also enhances the intramolecular through space charge transfer (TSCT) process. Spiral distributed phenoxazine and 2‐(trifluoromethyl)‐9H‐thioxanthen‐9‐one‐10,10‐dioxide act as donor and acceptor units, respectively. The resulting TADF enantiomers, (rac)‐OSFSO, display emission maxima at 470 nm, small singlet‐triplet energy gap (ΔEST) of 0.022 eV and high photoluminescence quantum yield (PLQY) of 81.2 % in co‐doped film. The circularly polarized OLEDs (CP‐OLEDs) based on (R)‐OSFSO and (S)‐OSFSO display obvious circularly polarized electroluminescence (CPEL) signals with dissymmetry factor up to 3.0×10−3 and maximum external quantum efficiency (EQEmax) of 20.0 %. Moreover, the devices show remarkably low efficiency roll‐off with an EQE of 19.3 % at 1000 cd m−2 (roll‐off ca. 3.5 %), which are among the top results of CP‐OLEDs.
Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Yi‐Pin Zhang, Xiao Liang, Xu‐Feng Luo, Shi‐Quan Song, Si Li, Yi Wang, Zhi‐Ping Mao, Wen‐Ye Xu, You‐Xuan Zheng, Jing‐Lin Zuo, Yi Pan
doi.org/10.1002/anie.202015411
N‐ or Cα‐methylation of a cyclic peptide increases cell‐membrane permeability only when it connects or extends existing hydrophobic patches. Positional isomers, with the same molecular weight, hydrogen bond donors/acceptors, rotatable bonds, calculated LogP, topological polar surface area, and total hydrophobic surface area, can have different membrane permeabilities that correlate with the size of the largest continuous hydrophobic surface patch.
N‐ or C‐methylation in natural and synthetic cyclic peptides can increase membrane permeability, but it remains unclear why this happens in some cases but not others. Here we compare three‐dimensional structures for cyclic peptides from six families, including isomers differing only in the location of an N‐ or Cα‐methyl substituent. We show that a single methyl group only increases membrane permeability when it connects or expands hydrophobic surface patches. Positional isomers, with the same molecular weight, hydrogen bond donors/acceptors, rotatable bonds, calculated LogP, topological polar surface area, and total hydrophobic surface area, can have different membrane permeabilities that correlate with the size of the largest continuous hydrophobic surface patch. These results illuminate a key local molecular determinant of membrane permeability.
Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Huy N. Hoang, Timothy A. Hill, David P. Fairlie
doi.org/10.1002/anie.202012643
Organic molecular passivators with different terminal groups are synthesized, which can effectively passivate the surface defects of MAPbI3‐based films by forming mixed‐phase perovskite nanograins. Moreover, highly efficient PeLEDs with EQE of 15.6 % are achieved by utilizing an imidazolium terminated passivator. This work opens up a new opportunity of molecular engineering for the development of high‐performance PeLEDs.
Metal halide perovskites are promising for applications in light‐emitting diodes (LEDs), but still suffer from defects‐mediated nonradiative losses, which represent a major efficiency‐limiting factor in perovskite‐based LEDs (PeLEDs). Reported here is a strategy to synthesize molecular passivators with different anchoring groups for defects passivation. The passivated perovskite thin films exhibit improved optoelectronic properties as well as reduced grain size and surface roughness, thus enable highly efficient PeLEDs with an external quantum efficiency of 15.6 % using an imidazolium terminated passivator. Further demonstrated is that the in situ formation of low‐dimensional perovskite phase on the surface of three‐dimensional perovskite nanograins is responsible for surface defects passivation, which leads to significantly enhanced device performance. Our results provide new fundamental insights into the role of organic molecular passivators in boosting the performance of PeLEDs.
Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Aihui Liang, Kang Wang, Yao Gao, Blake P. Finkenauer, Chenhui Zhu, Linrui Jin, Libai Huang, Letian Dou
doi.org/10.1002/anie.202100243
A practical and straightforward method to reduce the defects of polycrystalline perovskite films is exploited by introducing functional fluorinated molecules at two different stages of film formation. The PSCs based on the DP strategy can simultaneously improve device performance and stability by effectively inhibiting the formation of superoxide species due to minimized defects at the perovskite surface and GBs.
In recent years, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has witnessed rapid progress. Nevertheless, the pervasive defects prone to non‐radiative recombination and decomposition exist at the surface and the grain boundaries (GBs) of the polycrystalline perovskite films. Herein, we report a comprehensive dual‐passivation (DP) strategy to effectively passivate the defects at both surface and GBs to enhance device performance and stability further. Firstly, a fluorinated perylene‐tetracarboxylic diimide derivative is permeated in the perovskite metaphase during antisolvent treatment, and then a fluorinated bulky aromatic ammonium salt is introduced over the annealed perovskite. The reduction of defect density can be unambiguously proved by the superoxide species generation/quenching reaction. As a result, optimized planar PSCs demonstrate a decreased open‐circuit voltages deficit from 0.47 to 0.39 V and the best efficiency of 23.80 % from photocurrent scanning with a stabilized maximum power output efficiency of 22.99 %. Without encapsulation, one typical device can maintain over 85 % of the initial efficiency after heating on a hot plate at 100 °C for 30 h under relative humidity (RH) of 70 %. When the device is aged under 30±5 % RH, over 97 % of its initial PCE is retained after 1700 h.
Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Qin Zhou, Yifeng Gao, Chunsheng Cai, Zhuangzhuang Zhang, Jianbin Xu, Zhongyi Yuan, Peng Gao
doi.org/10.1002/anie.202017148
Barriers to reaction: The [2+1] cycloaddition reaction of a metal carbene with an alkene is investigated through DFT calculations. Efficient cyclopropanation by the silver catalyst is attributed to the barrierless concerted cycloaddition step, and the kinetic inhibition of side reaction by a high concentration of alkene.
The [2+1] cycloaddition reaction of a metal carbene with an alkene can produce important cyclopropane products for synthetic intermediates, materials, and pharmaceutical applications. However, this reaction is often accompanied by side reactions, such as coupling and self‐coupling, so that the yield of the cyclopropanation product of non‐silver transition‐metal carbenes and hindered alkenes is generally lower than 50 %. To solve this problem, the addition of a low concentration of diazo compound (decomposition of sulfonyl hydrazones) to alkenes catalyzed by either CuOAc or PdCl2 was studied, but side reactions could still not be avoided. Interestingly, however, the yield of cyclopropanation products for such hindered alkenes were as high as 99 % with AgOTf as a catalyst. To explain this unexpected phenomenon, reaction pathways have been computed for four different catalysts by using DFT. By combining the results of these calculations with those obtained experimentally, it can be concluded that the efficiency of the silver catalyst is due to the barrierless concerted cycloaddition step and the kinetic inhibition of side reactions by a high concentration of alkene.
Wiley: Chemistry – A European Journal: Table of Contents
Authors: Yong Wu, Shanshan Cao, Iskander Douair, Laurent Maron, Xihe Bi
chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.202005193
Genetic activation artificially induced a plasmid‐encoded natural product biosynthetic gene cluster and activated the complex biosynthesis of a previously unknown cytotoxin named sandarazol. Its biosynthesis is unique in featuring the genetic blueprint for the formation of intriguing structural features such as an α‐chlorinated ketone, an epoxyketone, and a rare (2R)‐2‐amino‐3‐(N,N‐dimethylamino)‐propionic acid building block.
Herein, we describe a new plasmid found in Sandaracinus sp. MSr10575 named pSa001 spanning 209.7 kbp that harbors a cryptic secondary metabolite biosynthesis gene cluster (BGC). Activation of this BGC by homologous‐recombination‐mediated exchange of the native promoter sequence against a vanillate inducible system led to the production and subsequent isolation and structure elucidation of novel secondary metabolites, the sandarazols A–G. The sandarazols contain intriguing structural features and very reactive functional groups such as an α‐chlorinated ketone, an epoxyketone, and a (2R)‐2‐amino‐3‐(N,N‐dimethylamino)‐propionic acid building block. In‐depth investigation of the underlying biosynthetic machinery led to a concise biosynthetic model for the new compound family, including several uncommon biosynthetic steps. The chlorinated congener sandarazol C shows an IC50 value of 0.5 μm against HCT 116 cells and a MIC of 14 μm against Mycobacterium smegmatis, which points at the sandarazols’ potential function as defensive secondary metabolites or toxins.
Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Fabian Panter, Chantal D. Bader, Rolf Müller
doi.org/10.1002/anie.202014671
Solid‐state filling of a stable phosphorus ylid open‐cage fullerene is followed by heating, inducing an in situ intramolecular Wittig reaction to reduce the size of the cage opening and trapping a single gas atom or molecule inside. Expensive gases can be compressed to high pressure, leading to high incorporation of the endohedral species. Cage closure steps allow preparation of gram‐scale endohedral fullerenes including 3He@C60, HD@C60, and Ne@C60.
An open‐cage fullerene incorporating phosphorous ylid and carbonyl group moieties on the rim of the orifice can be filled with gases (H2, He, Ne) in the solid state, and the cage opening then contracted in situ by raising the temperature to complete an intramolecular Wittig reaction, trapping the atom or molecule inside. Known transformations complete conversion of the product fullerene to C60 containing the endohedral species. As well as providing an improved synthesis of large quantities of 4He@C60, H2@C60, and D2@C60, the method allows the efficient incorporation of expensive gases such as HD and 3He, to prepare HD@C60 and 3He@C60. The method also enables the first synthesis of Ne@C60 by molecular surgery, and its characterization by crystallography and 13C NMR spectroscopy.
Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Gabriela Hoffman, Mark C. Walkey, John Gräsvik, George R. Bacanu, Shamim Alom, Sally Bloodworth, Mark E. Light, Malcolm H. Levitt, Richard J. Whitby
doi.org/10.1002/anie.202100817
The early cavitation bubble timescales of ablation of gold and aluminum targets in water are illustrated. It is evident that intensive chemical reactions occur depending on the oxidation sensitivity of the ablated material leading to different ablation depths during single pulse nanosecond laser ablation in liquids.
Understanding the key steps that drive the laser‐based synthesis of colloids is a prerequisite for learning how to optimize the ablation process in terms of nanoparticle output and functional design of the nanomaterials. Even though many studies focus on cavitation bubble formation using single‐pulse ablation conditions, the ablation efficiency and nanoparticle properties are typically investigated under prolonged ablation conditions with repetition rate lasers. Linking single‐pulse and multiple‐pulse ablation is difficult due to limitations induced by gas formation cross‐effects, which occur on longer timescales and depend on the target materials’ oxidation‐sensitivity. Therefore, this study investigates the ablation and cavitation bubble dynamics under nanosecond, single laser pulse conditions for six different bulk materials (Au, Ag, Cu, Fe, Ti, and Al). Also, the effective threshold fluences, ablation volumes, and penetration depths are quantified for these materials. The thermal and chemical properties of the corresponding bulk materials not only favor the formation of larger spot sizes but also lead to the highest molar ablation efficiencies for low melting materials such as aluminum. Furthermore, the concept of the cavitation bubble growth linked with the oxidation sensitivity of the ablated material is discussed. With this, evidence is provided that intensive chemical reactions occurring during the very early timescale of ablation are significantly enhanced by the bubble collapse.
Wiley: Chemistry – A European Journal: Table of Contents
Authors: Mark‐Robert Kalus, Stephan Barcikowski, Bilal Gökce
chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.202005087
