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21.
Daisuke Takano Matsumi Doe Yoshiki Morimoto Takamasa Kinoshita Kazuo Yoshihara 《Journal of heterocyclic chemistry》1999,36(1):221-224
The first synthesis of (-)-meridinol and (-)-3-epimeridinol was accomplished from (S)-malic acid. This synthesis unambiguously established the absolute stereochemistry of meridinol. 相似文献
22.
Kento Nishikibe Keisuke Nishikawa Momochika Kumagai Matsumi Doe Yoshiki Morimoto 《化学:亚洲杂志》2022,17(1):e202101137
There are marine cytotoxic bromotriterpenoids, named the thyrsiferol family that are structurally characterized by some tetrahydropyran (THP) and tetrahydrofuran (THF) rings. The thyrsiferol family belongs to natural products that are often difficult to determine their stereostructures even by the current, highly advanced spectroscopic methods, especially in acyclic systems including stereogenic tetrasubstituted carbon centers. In such cases, it is effective to predict and synthesize the possible stereostructures. Herein, to elucidate ambiguous stereostructures and unassigned absolute configurations of aplysiol B, laurenmariannol, and saiyacenol A, members of the thyrsiferol family, we carried out their asymmetric chemical syntheses featuring 6-exo and 5-exo oxacyclizations of epoxy alcohol precursors and 6-endo bromoetherification of a bishomoallylic alcohol. In this paper, we report total assignments of their stereostructures through their asymmetric chemical syntheses and also their preliminary cytotoxic activities against some tumor cells. These results could not have been achieved without depending on asymmetric total synthesis. 相似文献
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25.
Limit on flavor-changing neutral currents from a measurement of neutrino-electron elastic scattering
26.
27.
Pankaj?SehgalEmail author Hidekazu?Doe Manu?Sharma Daniel?E.?Otzen 《Colloid and polymer science》2005,283(11):1219-1225
The synergistic behavior of sodiumdodecylsulfate (SDS) and 1,2-diheptanoyl-sn-glycero-3-phosphocholine (DHPC) binary mixtures
has been studied with interfacial and pyrene fluorescence(I
1/ I
3) intensity measurements. From the interfacial data, the interfacial parameters; the maximum surface excess (Γmax), or the minimum area per molecule (A
min), and the surface pressure at the critical micellar concentration (πcmc) have been evaluated. The cmc value has been used for evaluating the free energies of micellization (ΔG
o
m). The mixed micelle formation was evaluated with the help of the Clint equation. The SDS plus DHPC mixed micelles showed
negative departure from ideality indicating synergistic interactions between the unlike components. The quantitative analysis
of mixed micelle, mixed monolayer and the composition of the mixed micelle was carried out with the help of regular solution
approximation. The interaction parameters, β and βσ, in the mixed micelle as well as in the mixed monolayer, respectively showed negative values indicating synergistic behavior
of SDS and DHPC molecules. 相似文献
28.
D. Sinclair A. L. Carter D. Kessler E. D. Earle P. Jagam J. J. Simpson R. C. Allen H. H. Chen P. J. Doe E. D. Hallman W. F. Davidson R. S. Storey A. B. McDonald G. T. Ewan H. -B. Mak B. C. Robertson 《Il Nuovo Cimento C》1986,9(2):308-317
Summary The proposal to build a heavy-water Čerenkov detector deep underground is discussed. The main physics objectives are to measure
the8B solar neutrino flux, to identify neutrino oscillations and to watch for gravitational collapse. The measurements of the
sources of background and the optical properties of heavy water, which are necessary to prove the feasibility of the detector,
are reported. The present status of the project is indicated.
Riassunto Si discute il progetto di costruire un rivelatore Čerenkov ad acqua pesante a grande profondità. Gli obiettivi fisici principali sono quelli di misurare il flusso di neutrini solati di8B, d'identificare le oscillazioni neutriniche e di osservare il collasso gravitazionale. Si riportano le misure delle sorgenti di background e le proprietà ottiche dell'acqua pesante, che sono necessarie per provare la fattibilità del rivelatore. Si indica lo stato attuale del progetto.
Резюме Обсуждается преложение о строительстве черенковского детектора на тяжелойводе. Основные физические задачи—измерение потока8B солнечных нейтрино, идентификация нейтринных осцилляций и наблюдение гравитационного коллапса Сообщаются результаты измерений источников фона и оптических свойств тяжелой воды, необходимые для вьшолнения этого детектора. Описывается состояние проекта в настоящее время.相似文献
29.
Tokutaro Ogata Misae Doe Aya Matsubara Eri Torii Chiaki Nishiura Arisa Nishiuchi Yusuke Kobayashi Tetsutaro Kimachi 《Tetrahedron》2014
The oxidative intramolecular cyclization of 3-hydroxyalkyl-1,2,4-trimethoxynaphthalenes was investigated. A series of 1,2-naphthoquinone fused cyclic ethers were synthesized directly from 3-hydroxyalkyl-1,2,4-trimethoxynaphthalenes by exposure to diammonium cerium (IV) nitrate. To understand the reaction mechanism, the intramolecular cyclization of 3-hydroxyalkyl-naphthoquinones that were formed as reaction intermediates was also examined. The results suggested that the reaction proceeds by a stepwise oxidation–cyclization mechanism. Using this methodology, five-step synthesis of rhinacanthone was achieved with high yield. 相似文献
30.
Cara L Ryan David C Baranowski Babykumari P Chitramuthu Suneil Malik Zhi Li Mingju Cao Sandra Minotti Heather D Durham Denis G Kay Christopher A Shaw Hugh PJ Bennett Andrew Bateman 《BMC neuroscience》2009,10(1):1-22