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Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]

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https://www.readbyqxmd.com/read/28639363/in-situ-generated-and-premade-1-copper-i-alkynes-in-cycloadditions
#1
REVIEW
Xinyan Wang, Xingyong Wang, Xuesong Wang, Jianlan Zhang, Chulong Liu, Yuefei Hu
The copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) was discovered in 2002, which has become the most remarkable example for "click chemistry" to date. In CuAAC reaction, 1-copper(I) alkyne has been recognized to be a key intermediate. However, many contradictory experimental results for this intermediate were reported in literature. For example, only the in-situ generated 1-copper(I) alkyne was used, while the premade 1-copper(I) alkyne proved to be inefficient under the standard conditions. The kinetic studies indicated that CuAAC reaction had a strict second-order dependence on Cu(I) and the DFT studies demonstrated that 1-copper(I) alkyne intermediate should be a dinuclear copper(I) complex...
June 22, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28608630/precisely-tailored-dna-nanostructures-and-their-theranostic-applications
#2
REVIEW
Bing Zhu, Lihua Wang, Jiang Li, Chunhai Fan
A critical challenge in nanotechnology is the limited precision and controllability of the structural parameters, which brings about concerns in uniformity, reproducibility and performance. Self-assembled DNA nanostructures, as a newly emerged type of nano-biomaterials, possess low-nanometer precision, excellent programmability and addressability. They can precisely arrange various molecules and materials to form spatially ordered complex, resulting in unambiguous physical or chemical properties. Because of these, DNA nanostructures have shown great promise in numerous biomedical theranostic applications...
June 13, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28605572/manganese-mediated-homolytic-aromatic-substitution-with-phosphinylidenes
#3
REVIEW
Olivier Berger, Jean-Luc Montchamp
Carbon-phosphorus (C-P) bond-forming reactions via homolytic aromatic substitution (HAS) of non-functionalized substrates with phosphinylidene P(O)H compounds is becoming a useful synthetic tool for the preparation of aryl and heteroaryl phosphonates, phosphinates, and phosphine oxides. This review specifically covers recent work using manganese-mediated free radical processes. Several research groups employ expensive Mn(OAc)3 , whereas our own contributions focus on the novel and inexpensive Mn(OAc)2 /MnO2 system...
June 12, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28513996/conformational-dynamics-of-mrna-in-gene-expression-as-new-pharmaceutical-target
#4
REVIEW
Tamaki Endoh, Naoki Sugimoto
Gene expression involves concurrent and consecutive events of unidirectional nature, such as transcription occurring from 5' to 3' end and translation from N to C terminus. Recent functional studies have shown the importance of kinetically coupled nucleic acid folding events that influence gene expression processes. For example, mRNA conformational dynamics during transcription and translation regulate gene expression and subsequent protein functionalization. The structure, stability, and kinetic properties of nucleic acids are sensitive to the intracellular molecular environment and can be regulated by using artificially developed molecules...
May 17, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28508470/catalytic-asymmetric-inverse-electron-demand-hetero-diels-alder-reactions
#5
REVIEW
Mingsheng Xie, Lili Lin, Xiaoming Feng
In this review, the recent developments in catalytic asymmetric inverse-electron-demand hetero-Diels-Alder reaction, which is recognized as one of the most powerful routes to construct highly functionalized and enantioenriched six-membered heterocycles, are described. The article is organized on the basis of different kinds of electron-deficient heterodienes, including α,β-unsaturated ketones/aldehydes, o-benzoquinones, α,β-unsaturated imines, N-aryl imines, o-benzoqinone imides, and other aza-olefins.
May 16, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28488753/cascades-of-interrupted-pummerer-reaction-sigmatropic-rearrangement
#6
REVIEW
Hideki Yorimitsu
A new class of Pummerer chemistry has emerged as a powerful tool in organic synthesis. The new technology consists of a beautiful cascade of an interrupted Pummerer reaction and the subsequent [3,3] sigmatropic rearrangement. The interrupted Pummerer reactions of alkenyl or aryl sulfoxides with unsaturated nucleophiles such as allylic silanes, ketones, and phenols provide sulfonium intermediates, which are ready to undergo smooth charge-accelerated [3,3] sigmatropic rearrangement with excellent to exclusive regioselectivity...
May 10, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28485131/physicochemical-nature-of-perfluoroalkyl-compounds-induced-by-fluorine
#7
REVIEW
Takeshi Hasegawa
Perfluoroalkyl (Rf ) compounds have unique characters represented by a significantly high hydrophobic property, which often makes us consider that Rf groups should be interacted with each other via the 'hydrophobic interaction' as found for a normal hydrocarbon. Due to a similar intuitive and simplistic speculation, the Rf -specific material properties have long been enveloped in darkness for comprehensive understanding, which should lucidly be discussed within a framework of physical chemistry. Here, we show studies on the stratified dipole arrays (SDA) theory, which readily explains the Rf -specific material characters in a comprehensive manner based on only a few fundamental physical parameters of fluorine...
May 9, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28480626/helical-mesoporous-tantalum-oxide-nanotubes-formation-optical-activity-and-applications
#8
REVIEW
Yangyang He, Yonggang Yang
Nanomaterials with helical morphologies have attracted much attention owing to their potential applications as nanosprings, chirality sensors and in chiral optics. Single-handed helical Ta2 O5 nanotubes prepared through a supramolecular templating approach are described. The handedness is controlled by that of the organic self-assemblies of chiral low-molecular-weight gelators (LMWGs). The chiral LMWGs self-assemble into single-handed twisted nanoribbons through H-bonding, hydrophobic association, and π-π stacking...
May 8, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28467681/luminescent-strategies-for-label-free-g-quadruplex-based-enzyme-activity-sensing
#9
REVIEW
Dik-Lung Ma, Zhen-Zhen Dong, Kasipandi Vellaisamy, Ka-Man Cheung, Guanjun Yang, Chung-Hang Leung
By catalyzing highly specific and tightly controlled chemical reactions, enzymes are essential to maintaining normal cellular physiology. However, aberrant enzymatic activity can be linked to the pathogenesis of various diseases. Therefore, the unusual activity of particular enzymes can represent testable biomarkers for the diagnosis or screening of certain diseases. In recent years, G-quadruplex-based platforms have attracted wide attention for the monitoring of enzymatic activities. In this Personal Account, we discuss our group's works on the development of G-quadruplex-based sensing system for enzyme activities by using mainly iridium(III) complexes as luminescent label-free probes...
May 3, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28452190/practical-synthesis-of-both-enantiomeric-amino-acid-mannich-and-aldol-derivatives-by-asymmetric-organocatalysis
#10
REVIEW
Yan Liu, Natarajan Arumugam, Abdulrahman I Almansour, Raju Suresh Kumar, Keiji Maruoka
In this account, we describe our recent developments in organocatalyzed asymmetric methodologies for the practical synthesis of both enantiomers. The synthesis of both enantiomeric products by using both enantiomeric catalysts is the most traditional way. In addition, use of two pseudoenantiomeric catalysts provides a more practical approach for the synthesis of both enantiomeric products. Even more efficient is the use of a single enantiomeric catalyst in the presence or absence of certain additives for obtaining both enantiomeric products...
April 27, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28444986/supported-ionic-liquids-a-versatile-and-useful-class-of-materials
#11
REVIEW
Vincenzo Campisciano, Francesco Giacalone, Michelangelo Gruttadauria
Supported ionic liquids (SILs) represent a class of materials with peculiar properties and a huge potential regarding their possible applications in different fields of chemistry. Herein, we report our ongoing research about the use of SILs as support for organocatalysts, their role as catalysts themselves, and their application as support and stabilizers of palladium nanoparticles (PdNPs). The use of SILs based materials allowed achieving good results. Moreover, in some cases, after the functionalization of the catalytic species with an ion-tag moiety, a release and catch approach was employed in order to improve the catalytic activity and to facilitate the recovery of the hybrid system formed by the catalyst adsorbed onto SILs materials...
April 26, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28418111/toward-the-dark-matter-of-natural-products
#12
REVIEW
Toshiyuki Wakimoto
Considering the dynamic features of natural products, our access toward exploring the entire diversity of natural products has been quite limited. It is challenging to assess the diversity of natural products by using conventional analytical methods, even with tandem chromatographic techniques, such as LC-MS and GC-MS. This viewpoint is supported by the sequencing analyses of microbial genomes, which have unveiled the potential of secondary metabolite production far exceeding the number of isolated molecules...
April 18, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28402607/frustrated-lewis-pair-chemistry-searching-for-new-reactions
#13
REVIEW
Gerald Kehr, Gerhard Erker
Frustrated Lewis pair chemistry has taken a steep development in the recent years. It offers possibilities of developing new variants of known reactions and of finding new chemical transformations. This is demonstrated and described by the recently developed FLP-formylborane chemistry, which has led to the formation of the unique (η(2) -formylborane)FLP adducts and opened a way of preparing a genuine formylborane compound, which shows an interesting follow-up chemistry. FLPs have helped finding phosphorus analogues of the enamine Stork reaction and the Claisen reaction...
April 12, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28394410/nanotechnology-for-electroanalytical-biosensors-of-reactive-oxygen-and-nitrogen-species
#14
REVIEW
Rajesh Seenivasan, Charles Kolodziej, Chandran Karunakaran, Clemens Burda
Over the past several decades, nanotechnology has contributed to the progress of biomedicine, biomarker discovery, and the development of highly sensitive electroanalytical / electrochemical biosensors for in vitro and in vivo monitoring, and quantification of oxidative and nitrosative stress markers like reactive oxygen species (ROS) and reactive nitrogen species (RNS). A major source of ROS and RNS is oxidative stress in cells, which can cause many human diseases, including cancer. Therefore, the detection of local concentrations of ROS (e...
April 10, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28387472/polymeric-1-h-mri-probes-for-visualizing-tumor-in-vivo
#15
REVIEW
Teruyuki Kondo, Yu Kimura, Hisatsugu Yamada, Yasuhiro Aoyama
Magnetic resonance imaging (MRI) has become a prominent non- or low-invasive imaging technique, providing high-resolution, three-dimensional images as well as physiological information about tissues. Low-molecular-weight Gd-MRI contrast agents (CAs), such as Gd-DTPA (DTPA: diethylenetriaminepentaacetic acid), are commonly used in the clinical diagnosis, while macromolecular Gd-MRI CAs have several advantages over low-molecular-weight Gd-MRI CAs, which help minimize the dose of CAs and the risk of side effects...
April 7, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28387469/elucidation-of-biosynthetic-pathways-of-natural-products
#16
REVIEW
Shinji Kishimoto, Yuta Tsunematsu, Michio Sato, Kenji Watanabe
During the last decade, we have revealed biosynthetic pathways responsible for the formation of important and chemically complex natural products isolated from various organisms through genetic manipulation. Detailed in vivo and in vitro characterizations enabled elucidation of unexpected mechanisms of secondary metabolite biosynthesis. This personal account focuses on our recent efforts in identifying the genes responsible for the biosynthesis of spirotryprostatin, aspoquinolone, Sch 210972, pyranonigrin, fumagillin and pseurotin...
April 7, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28378920/application-of-fischer-indolization-under-green-conditions-using-deep-eutectic-solvents
#17
REVIEW
Sambasivarao Kotha, Chandravathi Chakkapalli
Indole and its derivatives captured the attention of organic chemists due to their applications in medicinal chemistry. The examples covered here are intricate polycyclic indole derivatives and these include: azapolyquinanes, cyclophanes, spirocycles and other heterocycles. We found that deep eutectic mixture such as L-(+)-tartaric acid (TA) and dimethyl urea (DMU) is useful to prepare complex unnatural indole derivatives. These conditions from time to time produced indole derivatives which are not possible by conventional methods...
April 5, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28375578/platinum-group-metal-free-catalysts-for-hydrogen-evolution-reaction-in-microbial-electrolysis-cells
#18
REVIEW
Heyang Yuan, Zhen He
Hydrogen gas is a green energy carrier with great environmental benefits. Microbial electrolysis cells (MECs) can convert low-grade organic matter to hydrogen gas with low energy consumption and have gained a growing interest in the past decade. Cathode catalysts for the hydrogen evolution reaction (HER) present a major challenge for the development and future applications of MECs. An ideal cathode catalyst should be catalytically active, simple to synthesize, durable in a complex environment, and cost-effective...
April 4, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28375569/1-8-naphthalimide-a-potent-dna-intercalator-and-target-for-cancer-therapy
#19
REVIEW
Runjhun Tandon, Vijay Luxami, Harsovin Kaur, Nitin Tandon, Kamaldeep Paul
The poor pharmacokinetics, side effects and particularly the rapid emergence of drug resistance compromise the efficiency of clinically used anticancer drugs. Therefore, the discovery of novel and effective drugs is still an extremely primary mission. Naphthalimide family is one of the highly active anticancer drug based upon effective intercalator with DNA. In this article, we review the discovery and development of 1,8-naphthalimide moiety, and, especially, pay much attention to the structural modifications and structure activity relationships...
April 4, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28371211/understanding-and-practical-use-of-ligand-and-metal-exchange-reactions-in-thiolate-protected-metal-clusters-to-synthesize-controlled-metal-clusters
#20
REVIEW
Yoshiki Niihori, Sakiat Hossain, Sachil Sharma, Bharat Kumar, Wataru Kurashige, Yuichi Negishi
It is now possible to accurately synthesize thiolate (SR)-protected gold clusters (Aun (SR)m ) with various chemical compositions with atomic precision. The geometric structure, electronic structure, physical properties, and functions of these clusters are well known. In contrast, the ligand or metal atom exchange reactions between these clusters and other substances have not been studied extensively until recently, even though these phenomena were observed during early studies. Understanding the mechanisms of these reactions could allow desired functional metal clusters to be produced via exchange reactions...
March 29, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
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