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81.
Belous K Shapkin M Sokolov A Abe K Abe K Adachi I Aihara H Anipko D Arinstein K Aulchenko V Aushev T Bakich AM Barberio E Bay A Bedny I Bitenc U Bizjak I Blyth S Bondar A Bozek A Bracko M Browder TE Chang MC Chen A Chen KF Chen WT Cheon BG Chistov R Choi Y Choi YK Cole S Dalseno J Drutskoy A Eidelman S Epifanov D Fratina S Fujikawa M Gabyshev N Gershon T Gokhroo G Golob B Ha H Haba J Hasegawa Y Hayasaka K Hayashii H Hazumi M Heffernan D Hokuue T Hoshi Y Hou S Hou WS Iijima T Ikado K Imoto A 《Physical review letters》2007,99(1):011801
The mass of the tau lepton has been measured in the decay mode tau-->3pinutau using a pseudomass technique. The result obtained from 414 fb-1 of data collected with the Belle detector is Mtau=[1776.61+/-0.13(stat)+/-0.35(sys)] MeV/c2. The upper limit on the relative mass difference between positive and negative tau leptons is |Mtau+-Mtau-|/Mtau<2.8 x 10-4 at 90% confidence level. 相似文献
82.
83.
Formal Synthesis of Sarain A: Intramolecular Cycloaddition of an Eight‐Membered Cyclic Nitrone to Construct the 2‐Azabicyclo[3.3.1]nonane Framework 下载免费PDF全文
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
84.
Total Synthesis of Proposed Structure of Yuremamine and All Diastereomers Using [3+2]‐Cycloaddition of Platinum‐Containing Azomethine Ylide 下载免费PDF全文
Tomoya Ohyama Masako Uchida Prof.Dr. Hiroyuki Kusama Prof. Dr. Nobuharu Iwasawa 《化学:亚洲杂志》2015,10(9):1850-1853
Total synthesis of the proposed structure of yuremamine has been achieved for the first time based on the intermolecular [3+2]‐cycloaddition reaction of the platinum‐containing azomethine ylide. All the possible diastereomers of yuremamine were also synthesized via the common intermediate. Through these syntheses, it was confirmed that the proposed structure of yuremamine and the diastereomers differ from the natural product. 相似文献
85.
Dr. Shinichiro Fuse Ayako Ikebe Kazuya Oosumi Tomoya Karasawa Keisuke Matsumura Dr. Miho Izumikawa Dr. Kohei Johmoto Dr. Hidehiro Uekusa Dr. Kazuo Shin‐ya Prof. Takayuki Doi Prof. Takashi Takahashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(26):9454-9460
An asymmetric total synthesis of ent‐pyripyropene A was achieved by a convergent synthetic route. We used our originally developed TiIII‐catalyzed radical cyclization to construct an AB‐ring portion that consisted of a trans‐decalin skeleton with five contiguous stereogenic centers. The coupling between the AB‐ring and the DE‐ring portions, and a subsequent C‐ring cyclization, led to the total synthesis of ent‐pyripyropene A. An evaluation of the insecticidal activity of ent‐pyripyropene A against two aphid species revealed that ent‐pyripyropene A was 35–175 times less active than naturally occurring pyripyropene A. This result indicated that the biological target of pyripyropene A recognizes the absolute configuration of pyripyropene A. 相似文献
86.
Shi-jing Sun Tomoya Imai Junji Sugiyama Satoshi Kimura 《Cellulose (London, England)》2017,24(5):2017-2027
Cellulose is a major biopolymer on the earth that is produced by cellulose synthase in the cell membrane of living organisms. Cellulose synthase is a hetero-subunit complex composed of several different protein subunits, and is visualized as a supermolecular complex called a “terminal complex” by electron microscopy. Such supermolecular organization of an enzyme complex is believed to be important for the fiber formation or crystallization of cellulose microfibrils in cellulose biosynthesis. In the case of the cellulose-producing bacterium Acetobacter, it is hypothesized that the enzyme complex includes at least six subunits given its genetic constitution. However, to date, only three of these molecules have been experimentally confirmed as the subunits included in the terminal complex: CesB, CesD, and ccp2. In this study, we used fluorescence immuno-microscopy to show that CesA protein, the catalytic subunit, is included in the terminal complex of Acetobacter. Furthermore we discuss the obtained microscopic data for improving our understanding of the molecular organization of the bacterial cellulose synthase complex. 相似文献
87.
Nakano M Kishi R Yoneda K Inoue Y Inui T Shigeta Y Kubo T Champagne B 《The journal of physical chemistry. A》2011,115(31):8767-8777
The third-order nonlinear optical (NLO) properties, at the molecular level, the static second hyperpolarizabilities, γ, of supermolecular systems composed of phenalenyl and pyrene rings linked by acetylene units are investigated by employing the long-range corrected spin-unrestricted density functional theory, LC-UBLYP, method. The phenalenyl based superethylene, superallyl, and superbutadiene in their lowest spin states have intermediate diradical characters and exhibit larger γ values than the closed-shell pyrene based superpolyene systems. The introduction of a positive charge into the phenalenyl based superallyl radical changes the sign of γ and enhances its amplitude by a factor of 35. Although such sign inversion is also observed in the allyl radical and cation systems in their ground state equilibrium geometries, the relative amplitude of γ is much different, that is, |γ(regular allyl cation)/γ(regular allyl radical)| = 0.61 versus |γ(phenalenyl based superallyl cation)/γ(phenalenyl based superallyl radical)| = 35. In contrast, the model ethylene, allyl radical/cation, and butadiene systems with stretched carbon-carbon bond lengths (2.0 ?), having intermediate diradical characters, exhibit similar γ features to those of the phenalenyl based superpolyene systems. This exemplifies that the size dependence of γ as well as its sign change by introducing a positive charge on the phenalenyl based superpolyene systems originate from their intermediate diradical characters. In addition, the change from the lowest to the highest π-electron spin states significantly reduces the γ amplitudes of the neutral phenalenyl based superpolyene systems. For phenalenyl based superallyl cation, the sign inversion of γ (from negative to positive) is observed upon switching between the singlet and triplet states, which is predicted to be associated with a modification of the balance between the positive and negative contributions to γ. The present study paves the way toward designing a variety of open-shell NLO supermolecular systems composed of phenalenyl radical building blocks. 相似文献
88.
1,2,3-Benzotriazin-4(3H)-ones and 1,2,3,4-benzothiatriazine 1,1(2H)-dioxide reacted with isocyanides in the presence of a palladium catalyst to give 3-(imino)isoindolin-1-ones and 3-(imino)thiaisoindoline 1,1-dioxides, respectively, in high yield. An intermediate azapalladacycle was generated through denitrogenation of the triazine moiety, and an isocyanide was incorporated therein. 相似文献
89.
A new methodology for aromatic difluoromethylation is described. Aryl iodides reacted with α-silyldifluoroacetates upon treatment with copper catalyst in DMSO or DME to give the corresponding aryldifluoroacetates in moderate to good yields. The subsequent hydrolysis of aryldifluoroacetates and KF-promoted decarboxylation afforded a variety of difluoromethyl aromatics. 相似文献
90.
Tachi T Hase T Okamoto Y Kaji N Arima T Matsumoto H Kondo M Tokeshi M Hasegawa Y Baba Y 《Analytical and bioanalytical chemistry》2011,401(7):2301-2305
Microchip analysis is a promising method for therapeutic drug monitoring. This led us to evaluate a microchip-based fluorescence
polarization immunoassay (FPIA) system for point-of-care testing on patients being treated with theophylline. The sera were
collected from 20 patients being treated with theophylline. Fluorescence polarization was measured on the microchip and theophylline
concentrations in serum were obtained. Regression analysis of the correlations was done between the results given by the microchip-based
FPIA and the conventional cloned enzyme donor immunoassay (CEDIA), and between the results given by the microchip-based FPIA
and the conventional particle-enhanced turbidimetric inhibition immunoassay (PETINIA). We successfully carried out a quantitative
analysis of theophylline in serum at values near its therapeutic range in 65 s. The results obtained by the microchip-based
FPIA correlated well with CEDIA and PETINIA results; the correlation coefficients (R
2) were 0.986 and 0.989, respectively. The FPIA system is a simple and rapid method for point-of-care testing of drugs in serum,
and its accuracy is the same as the conventional CEDIA and PETINIA. It is essential to use real samples from patients and
to confirm good correlations with conventional methods for a study on the realization of microchip. 相似文献