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81.
Kohei HayashidaHideaki Fujii Shigeto HirayamaToru Nemoto Hiroshi Nagase 《Tetrahedron》2011,67(35):6682-6688
We describe the rearrangement of a carbamoylepoxy 4,5α-epoxymorphinan derivative that provided a novel 4,5α-epoxymorphinan derivative with an oxazatricyclodecane structure via an oxabicyclo[2.2.2]octane intermediate. We proposed the mechanism of the rearrangement reaction based on results observed in different deprotonation conditions. Epimerization occurred during rearrangement under reversible, but not irreversible, deprotonation conditions. The rearrangement product had a novel fundamental structure with moderate affinities for opioid receptors (Ki (μ)=47.7 nM, Ki (δ)=174.6 nM, and Ki (κ)=248.1 nM). Thus, the rearrangement products might have high potency as opioid ligands. 相似文献
82.
Polycationic‐Shelled Capsular and Tubular Nanostructures and Their Anionic–Guest Binding Properties
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Dr. Kohei Yazaki Dr. Yoshihisa Sei Prof. Dr. Munetaka Akita Dr. Michito Yoshizawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(49):17557-17561
For the development of novel nanospace with unique electrostatic character, we prepared new capsular and tubular nanostructures by the quantitative assembly of metal ions and bent bisacridinium ligands. The capsule and tube have closed spherical and open cylindrical cavities, respectively, with diameters of around 1 nm surrounded by cationic polyaromatic panels. Thanks to the facile synthetic protocol (three steps), another polycationic capsule with an elliptical nanocavity was also prepared by using an elongated ligand. In spite of the absence of pendant hydrophilic groups, the spherical polyaromatic capsule shows sufficient water solubility due to the polycationic shell. Moreover, the highly cationic cavity (12+) can selectively encapsulate anionic organic compounds in water. 相似文献
83.
Stereoselective Synthesis and Retentive Trapping of α‐Chiral Secondary Alkyllithiums Leading to Stereodefined α,β‐Dimethyl Carboxylic Esters
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Varvara Morozova Dr. Kohei Moriya Dr. Peter Mayer Prof. Dr. Paul Knochel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(29):9962-9965
The treatment of α‐chiral secondary alkyl iodides with tBuLi at ?100 °C leads to the corresponding secondary alkyllithiums with high retention of configuration. Subsequent quenching with various electrophiles such as Bu2S2, DMF, MeOB(OR)2, or Et2CO provides the desired products with retention of configuration. Furthermore, a transmetalation with CuBr?P(OEt)3 also allows retentive trapping with acid chlorides and ethylene oxide. The quenching of the resulting alkyllithiums with ClCO2Et furnishes stereoselectively syn‐ and anti‐ethyl‐2,3‐dimethyl ester carboxylates (d.r.>94 %). Related esters bearing three adjacent stereo‐controlled centers (stereotriads) have also been prepared. This method has been applied to the synthesis of the ant pheromone (±)‐lasiol in 26 % overall yield (four steps) with d.r.=97:3 starting from commercially available cis‐2,3‐epoxybutane. 相似文献
84.
[formula: see text] Alkyl-substituted chromium Fischer carbene complexes were found to react with various N-tosylimines to give beta-methoxy allylic amine derivatives under thermal conditions. This result is essentially distinct from the photochemical outcome in which beta-lactam derivatives are obtained. 相似文献
85.
Satoshi Shogen Masahiro Kawasaki Toshihiro Kondo Yukari Sato Kohei Uosaki 《应用有机金属化学》1992,6(6):533-536
An angle-resolved X-ray photoelectron spectroscopic study has been performed on structures of self-assembling systems, viz ferrocenylthiols on a gold (111) crystal. The angular dependence of the intensities of photoemission reveals that ferrocenyl groups are on the outermost layer, separated from the gold substrate by hydrocarbon chains of the thiol groups. 相似文献
86.
87.
Gold nanoclusters covered with 4-aminothiophenol (4-ATP) self-assembled monolayers (SAMs) were electrochemically assembled on an Au or ITO electrode. The assembly mechanism is discussed on the basis of results of electrochemical, FT-IR, and XPS measurements. The intensity of plasmon absorption of the gold nanocluster assembly was shown to be dependent on applied potential as a result of electrochemical doping/undoping of a counteranion in the polyaniline film. 相似文献
88.
We calculate scattering functions S(q-->,omega) of neutron Compton scattering (NCS) for a proton (deuteron) pair in the entangled state caused by the indistinguishability of particles. From the calculation, it is concluded that the effect of entanglement on the scattering intensity is undetectable in NCS experiments because of their high energy transfer and broad energy resolution. 相似文献
89.
90.
Tsuji H Terada M Toshimitsu A Tamao K 《Journal of the American Chemical Society》2003,125(25):7486-7487
On the basis of the UV absorption spectra of the anti,cisoid alternating oligosilanes, the first experimental clear-cut evidence was presented for the generally accepted idea that the sigma conjugation in polysilanes does not effectively extend through a tetrasilane fragment with a small dihedral angle such as a cisoid turn. 相似文献