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91.
Formal Synthesis of Sarain A: Intramolecular Cycloaddition of an Eight‐Membered Cyclic Nitrone to Construct the 2‐Azabicyclo[3.3.1]nonane Framework
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Dr. Takuya Higo Tomoya Ukegawa Dr. Satoshi Yokoshima Prof. Tohru Fukuyama 《Angewandte Chemie (International ed. in English)》2015,54(25):7367-7370
An enantioselective route to the tetracyclic skeleton of sarain A has been developed. Asymmetric reduction of an ynone introduced a chiral center which was transferred to the contiguous tertiary stereogenic centers through an Ireland–Claisen rearrangement. The 2‐azabicyclo[3.3.1]nonane framework was constructed by an unprecedented intramolecular cycloaddition of an eight‐membered cyclic nitrone. Using the steric bias of the bicyclic system, the quaternary carbon atom was constructed by a stereoselective aldol reaction. Further ring formations were performed by ring‐closing metathesis for the 13‐membered ring and an iodoamidation reaction for the pyrrolidine ring. The present synthesis has successfully provided an alternative route to the late‐stage intermediate of Overman’s synthesis. 相似文献
92.
Ryota Inoue Masashi Hasegawa Tohru Nishinaga Kenji Yoza Yasuhiro Mazaki 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(9):2772-2776
A series of thiacalix[n]dithiothiophenes (n=4–10) was prepared by a facile method and X‐ray analysis was used to determine the molecular structures of square‐ (4‐mer) and pentagonal‐shaped macrocycles (5‐mer). In the cyclic voltammograms, reversible multielectron redox processes, which are due to electronic delocalization, were observed at low oxidation potentials. The cyclic 4‐mer acted as a “Janus‐head” cavitand for two C60 molecules, whereas the 5‐ and 6‐mer formed stable 1:1 complexes with C60 . 相似文献
93.
Cover Picture: A Modular Synthesis of Conformationally Preorganised Extended β‐Strand Peptidomimetics (Chem. Eur. J. 42/2015)
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94.
Jo Yong-Hyun Joshi Bhupendra Sekino Tohru Kim Tae-Ho Lee Soo-Wohn 《Research on Chemical Intermediates》2017,43(9):5261-5269
Research on Chemical Intermediates - A comparative study was carried out on the photocatalytic properties depending on Jodifferent morphologies of Ag3PO4 fabricated by different methods, i.e. as... 相似文献
95.
Touge T Hakamata T Nara H Kobayashi T Sayo N Saito T Kayaki Y Ikariya T 《Journal of the American Chemical Society》2011,133(38):14960-14963
Newly developed oxo-tethered Ru amido complexes (R,R)-1 and their HCl adducts (R,R)-2 exhibited excellent catalytic performance for both asymmetric transfer hydrogenation and the hydrogenation of ketonic substrates under neutral conditions without any cocatalysts to give chiral secondary alcohols with high levels of enantioselectivity. 相似文献
96.
Makio Iwahashi Tadashi Nozaki Kazuyuki Kamaya Kenichi Taguchi Masahiro Fujita Yasutoshi Kasahara Hideyuki Minami Hideyo Matsuzawa Shinji Nakamura Katsuyoshi Harada Yukihiro Ozaki Tohru Inoue 《The Journal of chemical thermodynamics》2011,43(1):80-87
Phase behaviors of the binary mixtures composed of ethylene carbonate (EC) and aliphatic alcohols, ω-phenyl alcohols, and alkylbenzenes were investigated. In addition, heat of solution of EC into these organic solvents was measured. The EC/methanol and EC/ethanol systems gave homogeneous solution at the temperature above their liquidus lines, while the mixtures of EC and alcohols with longer alkyl chain showed a miscibility gap in a liquid phase and provided the monotectic-type phase diagram. The liquid–liquid phase separation region expanded with the increase in the alkyl chain length. A similar phase behavior was also observed for the mixtures of EC and alkylbenzenes. On the other hand, the EC mixtures with ω-phenyl alcohols showed no miscibility gap in a liquid phase at least up to 4-phenylbutan-1-ol which has C4 alkyl chain intervening between phenyl and hydroxyl groups. This result demonstrates that both of the hydroxyl and phenyl groups act to facilitate the mixing of aliphatic compounds with EC. The phase behavior of these EC mixtures was analyzed applying the modified regular solution model in which the pair interaction energy was regarded as free energy. The model calculation with the use of heat of solution of EC at infinite dilution as the pair interaction enthalpy reproduced well both of the experimentally obtained liquidus line and mutual solubility curve as well as monotectic point. 相似文献
97.
A series of star-shaped pyrrole-fused tetrathiafulvalene (TTF) oligomers 1-3 was synthesized via an S(N)Ar reaction of fluorinated benzenes with the pyrrolyl sodium salts. Electrochemical and chemical oxidations of 1-3 revealed that a radical cation moiety on each TTF unit was successfully accumulated in all oligomers. Self-assembled structures of neutral and oxidized species were characterized by SEM and XRD, and their conductive properties of the iodine-doped 1-3 as well as an intermolecular mixed-valence ion radical salt were investigated. 相似文献
98.
Miyagawa T Nagai K Yamada A Sugihara Y Fukuda T Fukuda T Uchida R Tomoda H Omura S Nagamitsu T 《Organic letters》2011,13(5):1158-1161
The first total synthesis of citridone A has been achieved through regioselective intramolecular iodocyclization and regio- and stereoselective Pd(0)-catalyzed coupling as key reactions. 相似文献
99.
Saigusa D Shibuya M Jinno D Yamakoshi H Iwabuchi Y Yokosuka A Mimaki Y Naganuma A Ohizumi Y Tomioka Y Yamakuni T 《Analytical and bioanalytical chemistry》2011,400(10):3635-3641
We recently demonstrated that nobiletin, a citrus flavonoid, exhibits anti-dementia action in animals. However, no determination methods for the content of nobiletin with beneficial action in the brain of nobiletin-administered animals have been developed, nor has its pharmacokinetics been revealed completely. Here, we established the high-performance liquid chromatography/photodiode array detection method for nobiletin determination using Bond Elut C18 SPE cartridges for extraction, where the calibration curve was linear over 0.025-10 ng, with coefficient of variation of less than 6.76%. This method enabled us to determine pharmacokinetic parameters of nobiletin given intraperitoneally or per os in the brain of mice. 相似文献
100.
The energy method in the Fourier space is useful in deriving the decay estimates for problems in the whole space Rn. In this paper, we study half space problems in and develop the energy method in the partial Fourier space obtained by taking the Fourier transform with respect to the tangential variable x′∈Rn−1. For the variable x1∈R+ in the normal direction, we use L2 space or weighted L2 space. We apply this energy method to the half space problem for damped wave equations with a nonlinear convection term and prove the asymptotic stability of planar stationary waves by showing a sharp convergence rate for t→∞. The result obtained in this paper is a refinement of the previous one in Ueda et al. (2008) [13]. 相似文献