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Chemistry, An Asian Journal

Rajneesh Misra
A set of 1,8-naphthalimide (NPI) substituted BODIPY dyads 1a-1c were designed and synthesized by the Pd-catalyzed Sonogashira cross-coupling reaction of ethynyl substituted NPI 1 with the meso-, β- and α- halogenated BODIPYs a, b and c, respectively. The BODIPY 1c exhibits red shifted absorption which suggests better electronic communication at the α-position of BODIPY as compared to meso and β positions which was further supported by the TD-DFT calculations. The optical band gap follows the order 1a>1b>1c...
July 16, 2018: Chemistry, An Asian Journal
Hongqian Cao, Yanfei Qi, Yang Yang, Lei Wang, Jiaheng Sun, Yue Li, Jiarui Xia, Hao Wang, Junbai Li
In recent years, one of main obstacles in a photodynamic therapy (PDT) process is that most of photosensitizers for PDT are excited by visible light with limited penetrating ability, resulting that most of applications of PDT are for superficial treatments. One of methods to increase the treatment depth is introducing a two-photon active technique into PDT, as TP-PDT. The difficulty here is how to obtain photosensitizers with enough large two-photon absorption cross-section. In this work, we constructed an organic nanocomplex which was composed with two-photon nano-aggregate as the core and photosensitizer as the shell...
July 15, 2018: Chemistry, An Asian Journal
Kishor Gulab Thorat, Mangalampalli Ravikanth
The first examples of stable dithia calix-corrphycenes were synthesized by treating appropriate tetrapyrranes with two equivalents of TFA in CH2Cl2 followed by oxidation using p-chloranil. Condensation of tetrapyrrane resulted in the formation of two unexpected dithia calix-corrphycenes which differ from each other at calix meso carbon centre and the two macrocycles were easily separated and isolated by column chromatography. The novel macrocycles were confirmed by X-ray crystallography and characterized by HR-MS, 1D, 2D NMR, absorption spectroscopy, cyclic voltammetry and TD-DFT studies...
July 15, 2018: Chemistry, An Asian Journal
Ryo Adachi, Motofusa Akiyama, Yoshitsugu Morita, Teruyuki Komatsu
This paper describes the synthesis and catalytic activities of stratiform protein microtube reactors containing a glucose oxidase (GOD) enzyme layer. The microtubes were fabricated by layer-by-layer assembly using microporous polycarbonate membrane with human serum albumin (HSA), poly(L-arginine) (PLA), and GOD. The GOD component was introduced into the tube wall as the innermost layer, the intermediate layer, or all internal protein layers. SEM observations revealed the formation of uniform hollow cylinders with ca...
July 13, 2018: Chemistry, An Asian Journal
To Ngai, Hang Jiang, Yunxing Li, Liangzhi Hong
Herein we report the ultilization of submicron Pickering emulsion (SPE) to encapsulate the enzyme (e.g., lipase from Candida sp.) in water droplets stabilized solely by hydrophobic solid or mesoporous silica nanoparticles in toluene for use in biphasic reaction. Because of the exceptionally high water/oil interfacial area and short diffusion distance of reagents in SPE, the catalytic performance of encapsulated lipase is evaluated by esterification of 1-hexanol and hexanoic acid under stirring-free condition, which is favourable to maintain the enzymatic activity...
July 10, 2018: Chemistry, An Asian Journal
Hyowon Seo, Misun Go, Heekyoung Choi, Ka Young Kim, Yeonweon Choi, Shim Sung Lee, Sung Ho Jung, Jong Hwa Jung
This paper describes the peculiar co-assembly supramolecular polymerization behavior of triphenylamine trisamide derivatives with D-alanine (T-ala) or glycine (T-gly) moieties. Concentration and temperature-dependent circular dichroism (CD) spectroscopy revealed that the heating curves of co-assemblies obtained at various molar ratios of T-ala to T-gly exhibited two distinct transition temperatures. The first transition was due to the transformation from coiled helical bundles to single helical fibers without handedness...
July 10, 2018: Chemistry, An Asian Journal
Ying Li, Yuxia Gao, Bo Wang, Jie Hao, Jun Hu, Yong Ju
In this research a series of random and block amphiphilic copolymers of norbornene derivatives containing biocompatible natural triterpenoid and oligo(ethylene glycol) pendants were synthesized by ring-opening metathesis polymerization. These copolymers were thermo- and pH-responsive, and could self-assemble into core-shell spherical micelles in aqueous water, hydrodynamic diameters of which were relevant to pH values and monomer sequences. By evaluating their loading and release capacity of hydrophobic molecules, it was found that 1) more content of the hydrophobic triterpenoid, higher of the loading capacity; 2) the release speed could be trigged by pH because of the deprotonation of carboxyl groups on triterpenoid...
July 9, 2018: Chemistry, An Asian Journal
Xuehai Yan, Yamei Liu, Luyang Zhao, Ruirui Xing, Tifeng Jiao, Weixing Song
Organic photothermal sensitizers, such as indocyanine green (ICG), have been widely explored in photothermal therapy as a good substitution of inorganic materials due to advantageous biosafety and strong absorption in the near-infrared region. However, their intrinsic low stability and rapid clearance from the body requires further modification for efficient therapeutic application. In this work, we employed a covalent assembly strategy by covalently cross-linking genipin and a functional bola-amino acid to fabricate stable and degradable nanoparticles capable of loading ICG...
July 6, 2018: Chemistry, An Asian Journal
Xuan-Hui Ouyang, Song Renjie, Jin-Heng Li
α-Carbony alkyl bromides are powerful reactive species for the formation of carbon-carbon bonds. Strategies relying on intermolecular C-H functionalization and cross-coupling reactions, also referred to as intramolecular cyclization, have been employed for the construction of alkenes, alkanes, ketones and other natural-product-like ring compounds from simple alkynes, alkenes and 1,n-enynes. In view of the important of this α-carbony alkyl bromides, especially the difloro carbony alkyl bromides, many researchers focused their efforts to develop facile and mild synthetic methods for the compounds with important biological activities...
July 6, 2018: Chemistry, An Asian Journal
Xi-Sheng Wang, Tao Wang, Yi-Ning Wang, Rui Wang
A rhodium(III)-catalyzed direct C-H alkynylation of a wide range of N-methylsulfoximines with (bromoethynyl)triisopropylsilane has been developed. This novel protocol is compatible with both S,S-diaryl sulfoximines and S,S-alkyl aryl sulfoximines, and demonstrates mild conditions, good functional group tolerance. The synthetic utility of this method has been demonstrated by subsequent various transformations of the products.
July 5, 2018: Chemistry, An Asian Journal
Suzanne Timmermans, Daan Vervoort, Lise Schoonen, Roeland Nolte, Jan van Hest
Capsids of the cowpea chlorotic mottle virus (CCMV) hold great promise for use as nanocarriers in vivo. A major drawback, however, is the lack of stability of the empty wild-type virus particles under physiological conditions. Here, we report on the assembly behavior and stability under nearly-physiological conditions of protein-based block copolymers composed of the CCMV capsid protein and two hydrophobic elastin-like polypeptides. UV-vis spectrometric studies, dynamic light scattering analysis, and transmission electron microscopy measurements demonstrate that both hybrid variants form stable capsids at pH 7...
July 5, 2018: Chemistry, An Asian Journal
Kang-Da Zhang, Ting-Ting Jin, Xiao-He Zhou, Yong-Fei Yin, Tian-Guang Zhan, Jiecheng Cui, Li-Juan Liu, Li-Chun Kong
The development of artificial self-assembling systems with dynamic photo-regulation features in aqueous solutions has drawn great attention owing to the potential applications in fabricating elaborate biological materials. Here we demonstrate the fabrication of water-soluble cucurbit[8]uril (CB[8])-mediated supramolecular polymers by connecting the fluorinated azobenzene (FAB) containing monomer through host-enhanced multiple charge-transfer interactions. The formation of the supramolecular polymers could be regulated through the visible-light-induced E/Z photoisomerization of the FAB units, which determines the encapsulation behaviour between CB[8] macrocycle and the monomers...
July 5, 2018: Chemistry, An Asian Journal
Philip J Marriott
In the past 15+ years, gas chromatography (GC) has undergone a renaissance in its implementation on the basis of the "disruptive" technology of comprehensive two-dimensional gas chromatography (GC×GC). With a foundation based upon a two-column GC separation approach, GC×GC significantly alters the classical multidimensional gas chromatography (MDGC) method by employing very fast separation on a second dimension (2 D) after a conventional one-dimensional (i.e., single column; 1D) column separation...
July 5, 2018: Chemistry, An Asian Journal
Ya-Ni Wang, Liang-Qiu Lu, Wen-Jing Xiao
Palladium-catalyzed allylic substitution reactions have become established as an important tool for the construction of carbon-carbon and carbon-heteroatom bonds in modern organic synthesis. However, controlling the regioselectivity of this type of transformation to afford chiral branched products, in addition to controlling the enantioselectivity, is a significant challenge. Excitingly, controlling nonbonding interactions between the substituents on the π-allyl-palladium intermediate and the nucleophile or palladium catalyst has been shown to be effective in achieving this goal...
July 4, 2018: Chemistry, An Asian Journal
Guillermo Valdomir, Soundararasu Senthilkumar, Dhandapany Ganapathy, Yun Zhang, Lutz F Tietze
A one pot borylation/Suzuki-Miyaura reaction of the 4-bromochromanone lactones 21 and 23, respectively, followed by cleavage of the methyl ether moieties gave the homodimeric chromanone lactones 10 and 11. Reaction of a 1:1 mixture of 21 and 23 under otherwise identical conditions gave a 1:1:2-mixture of the two homodimers 10 and 11 and the heterodimer 12. This is the first example of the preparation of a heterodimeric chromanone lactone. For the enantioselective synthesis of the starting material, phenol 17 was transformed into the chromane 18 using a Wacker-type cyclisation with 99 % ee and 80 % yield...
July 4, 2018: Chemistry, An Asian Journal
Tao Tu, Yang Zhang, Jiaquan Wang, Haibo Zhu
One of the NHC-iridium coordination assemblies containing 1,5-Cyclooctadiene (COD) and iodide ion has been demonstrated as robust, efficient, recyclable solid molecular catalyst for N-formylation of diverse primary and secondary amines with CO2 and H2 under mild reaction conditions. Remarkably, in the case of N,N-dimethyl-formamide production, even at 0.1 mol% catalyst loading under solvent free conditions, the solid catalyst can be readily recovered by simply filtration and reused more than 10 runs without obviously loss of activity, highlighting the feasibility in industry...
July 3, 2018: Chemistry, An Asian Journal
Yinjie Chen, Xing Feng, Zhicheng Sun, Dan Wang, Tao Yang, Ziyuan Zhao, Luhai Li, Xiaogong Wang, Haifeng Yu
Three-arm star azopyridinium salts self-organize into various morphologies in water/organic mixed solvents. Interesting AIE and self-assembling features are observed due to the strong interaction of the azopyridinium moieties with the high polar H2O molecules causing the salts to aggregate, which restricts the molecular motion and induces the fluorescence.
July 3, 2018: Chemistry, An Asian Journal
Yuhong Wang, Yiming Li, Xuefeng Jiang
Sulfur-containing compounds (SCCs) exist widely in, for example, natural sources, pharmaceuticals, materials, and foods. Their multifarious functions have stimulated scientists to construct them in greener and more efficient ways and further exploit their properties. Different photosensitizers with sulfur atoms have been developed and exploited. Furthermore, SCCs display excellent ability in hydrogen-atom-transfer reactions. In addition to acting as catalysts, SCCs can also be efficiently transformed under visible-light-promoted conditions...
July 3, 2018: Chemistry, An Asian Journal
Shihao Chen, Yu-Hua Shi, Ming Wang
Catalytic kinetic resolution is often the "method of choice" for the preparation of optically enriched functionalized compounds and, over the past decade, kinetic resolutions and dynamic kinetic resolutions catalyzed by N-heterocyclic carbenes (NHCs) have been employed for the synthesis of a variety of optically enriched functionalized molecules. Herein we provide an overview of reported NHC-catalyzed kinetic resolutions in terms of the structure of the substrate, the reaction type, and the activation mode...
July 3, 2018: Chemistry, An Asian Journal
Hongyu Qin, Jingchao Chen, Kangkui Li, Zhenxiu He, Yongyun Zhou, Baomin Fan
Enantioselective [2+2] cycloaddition reaction of azabenzonorbornadienes and oxabenzonorbornadienes with internal alkynes has been enabled by a catalyst system comprising Ni(COD)2 and (R)-SIPHOS-Ph-Mor. This transformation represents the first asymmetric [2+2] cycloaddition reaction of azabenzonorbornadienes with internal alkynes, providing a straightforward method to prepare four-membered carbocycles.
July 3, 2018: Chemistry, An Asian Journal
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