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排序方式: 共有711条查询结果,搜索用时 15 毫秒
701.
Mohamed S. H. Salem Ahmed Sabri Md. Imrul Khalid Hiroaki Sasai Shinobu Takizawa 《Molecules (Basel, Switzerland)》2022,27(24)
A novel double aza-oxa[7]helicene was synthesized from the commercially available N1,N4-di(naphthalen-2-yl)benzene-1,4-diamine and p-benzoquinone in two steps. Combining the acid-mediated annulation with the electrochemical sequential reaction (oxidative coupling and dehydrative cyclization) afforded this double hetero[7]helicene. Moreover, the structural and optical features of this molecule have been studied using X-ray crystallographic analysis, and the absorption and emission behaviors were rationalized based on DFT calculations. 相似文献
702.
Tomoya Shinke Mayu Itoh Takuma Wada Assist. Prof. Yuma Morimoto Assoc. Prof. Sachiko Yanagisawa Assoc. Prof. Hideki Sugimoto Prof. Minoru Kubo Prof. Shinobu Itoh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(59):14730-14737
Mechanistic studies are performed on the alkane hydroxylation with m-CPBA (m-chloroperbenzoic acid) catalyzed by nickel(II) complexes, NiII(L). In the oxidation of cycloalkanes, NiII(TPA) acts as an efficient catalyst with a high yield and a high alcohol selectivity. In the oxidation of adamantane, the tertiary carbon is predominantly oxidized. The reaction rate shows first-order dependence on [substrate] and [NiII(L)] but is independent on [m-CPBA]; vobs=k2[substrate][NiII(L)]. The reaction exhibited a relatively large kinetic deuterium isotope effect (KIE) of 6.7, demonstrating that the hydrogen atom abstraction is involved in the rate-limiting step of the catalytic cycle. Furthermore, NiII(L) supported by related tetradentate ligands exhibit apparently different catalytic activity, suggesting contribution of the NiII(L) in the catalytic cycle. Based on the kinetic analysis and the significant effects of O2 and CCl4 on the product distribution pattern, possible contributions of (L)NiII−O. and the aroyloxyl radical as the reactive oxidants are discussed. 相似文献
703.
Hiroto Uno Daichi Fujimoto Kyosuke Harada Chika Tanaka Prof. Dr. Norio Shibata 《ChemistryOpen》2021,10(5):518-522
Efficient synthesis of N,O-heterocyclic tetra-substituted trifluoromethyl-3,1-benzoxazines via a transition-metal-catalyzed decarboxylative intramolecular cyclization was achieved. The decarboxylation of N-benzoyl trifluoromethyl-benzoxazinones generated the amide oxygen nucleophile, allowing a selective internal C1-attack on Pd- or Cu-coordinated zwitterions, affording medicinally attractive tetra-substituted vinyl- or ethynyl-trifluoromethyl-3,1-benzoxazines. This protocol can be applied to the synthesis of perfluoroalkyl- and non-fluorinated 3,1-benzoxazines. 相似文献
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706.
Dr. Masaru Kondo Dr. Kento Nakamura Dr. Chandu G. Krishnan Prof. Hiroaki Sasai Assoc. Prof. Shinobu Takizawa 《Chemical record (New York, N.Y.)》2023,23(7):e202300040
This study presents recent advances in photoswitchable chiral organocatalysts and their applications in the photomodulation of enantioselective reactions. Under irradiation with an appropriate wavelength of light, the E/Z-photoisomerization of the photoresponsive units on the catalysts leads to the control of the catalytic activity and/or selectivity of the enantioselective reactions. Additionally, this study elucidates the design, synthesis, and catalytic application of the fabricated azobenzene BINOL-based photoswitchable chiral phase-transfer catalysts. This account will provide insights into the appropriate design of a photoswitchable chiral organocatalyst that can achieve both good enantioselectivity and photocontrol. 相似文献
707.
708.
Shuma Kaneyoshi Shun Murakami Takumi Ikeda Kazuhisa Fujimoto Satoshi Fujii Shinobu Sato Shigeori Takenaka 《Electroanalysis》2023,35(4):e202380401
To develop an electrochemical detection method for COVID-19, we have investigated the interaction between RG-1, a characteristic parallel four-strand RNA component of the COVID-19 genome, and cyclic ferrocenylnaphthalene diimides carrying different linker lengths 1 and 2 , which bind to RG-1 more strongly than cyclic naphthalene diimide 3 that lacks a ferrocene moiety. In particular, the binding affinity of 1 having short one showed the highest binding affinity to RG-1, and the redox current of 1 increased in the presence of RG-1 using a glassy carbon electrode. This increasing current of 1 in the presence of c-myc as a parallel G4 DNA or single-stranded RNA was lower than that in the presence of RG-1. Several RG-1 was electrochemically detected at the nanomolar level by 1 . 相似文献
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