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21.
Prof. Dr. Fumitoshi Shibahara Shun‐ichiro Kobayashi Toshifumi Maruyama Prof. Dr. Toshiaki Murai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(1):304-313
Addition reactions of thioamide dianions that were derived from N‐arylmethyl thioamides to imines and aziridines were carried out. The reactions of imines gave the addition products of N‐thioacyl‐1,2‐diamines in a highly diastereoselective manner in good‐to‐excellent yields. The diastereomeric purity of these N‐thioacyl‐1,2‐diamines could be enriched by simple recrystallization. The reduction of N‐thioacyl‐1,2‐diamines with LiAlH4 gave their corresponding 1,2‐diamines in moderate‐to‐good yields with retention of their stereochemistry. The oxidative‐desulfurization/cyclization of an N‐thioacyl‐1,2‐diamine in CuCl2/O2 and I2/pyridine systems gave the cyclized product in moderate yield and the trans isomer was obtained as the sole product. On the other hand, a similar cyclization reaction with antiformin (aq. NaClO) as an oxidant gave the cis isomer as the major product. The reactions of N‐tosylaziridines gave the addition products of N‐thioacyl‐1,3‐diamines with low diastereoselectivity but high regioselectivity and in good‐to‐excellent yields. The use of AlMe3 as an additive improved the efficiency and regioselectivity of the reaction. The stereochemistry of the obtained products was determined by X‐ray diffraction. 相似文献
22.
Copper‐Catalyzed CH Bond Direct Chalcogenation of Aromatic Compounds Leading to Diaryl Sulfides,Selenides, and Diselenides by Using Elemental Sulfur and Selenium as Chalcogen Sources Under Oxidative Conditions 下载免费PDF全文
Prof. Fumitoshi Shibahara Takafumi Kanai Eiji Yamaguchi Akika Kamei Takayuki Yamauchi Prof. Toshiaki Murai 《化学:亚洲杂志》2014,9(1):237-244
The reactions of aromatic compounds and elemental chalcogens catalyzed by a copper salt with molecular oxygen as an oxidant were carried out. The reaction of 3‐substituted imidazo[1,5‐a]pyridines and elemental sulfur in the presence of CuTC (copper(I) thiophenecarboxylate) gave the corresponding bisimidazopyridyl sulfides in good to quantitative yields. The reaction proceeded even under aerobic oxidation conditions. The use of a polar solvent was crucial for the reaction, and DMSO (dimethyl sulfoxide) in particular stimulated the reaction. The reaction could be applied to common aromatic compounds, such as N‐methyl indole and dialkyl anilines. The reaction of indole proceeded at the nucleophilic C3 position rather than at the acidic C2 position. In addition, the reaction of dialkyl anilines proceeded with an ortho, para orientation. The reactions of imidazopyridines and elemental selenium under similar conditions gave the corresponding bisimidazopyridyl diselenides along with bisimidazopyridyl monoselenides. The resulting diselenides were readily converted to the corresponding monoselenides with unreacted imidazopyridines under the same conditions. The reaction could be applied to the copolymerization of bifunctional bisimidazopyridines and elemental sulfur to give oligomeric copolymers in quantitative yield. 相似文献
23.
Journal of Visualization - To enrich the three-dimensional experimental details of vortex structures in rotating Rayleigh–Bénard convection, we established a technique... 相似文献
24.
Jun Koyanagi Keita Takeguchi Kazuki Murai Hirokazu Furue Nobuyuki Masuda 《Molecular Crystals and Liquid Crystals》2017,656(1):54-65
Blue-phase liquid crystals form three-dimensional structures in a self-organizing manner and are similar to living tissue structures such as the teeth of mice and collagen tissues. This study presents numerical results regarding the conditions under which blue-phase liquid crystals occur. The Monte Carlo simulations are performed by employing an improved Lennard–Jones potential that considers anisotropy and chirality. The conditions for the formation of the blue phase, which vary with respect to the chirality, are examined first. The relationship between the anisotropic parameters and the chiral parameter for the formation of the blue phase is discussed. Identical blue-phase structures are obtained, even when the cell size and molecular number are varied drastically. This discussion is useful for considering the scale-up problem, which is almost always a difficult issue for molecular-scale simulations. 相似文献
25.
The carbonylation of a phenyllithium containing an oxazoline group at the ortho position, followed by quenching with water, afforded a tricyclic compound, 3,3-dimethyl-2,3-dihydrooxazolo[2, 3-a]isoindol-5(9bH)-one, in 91% yield. This reaction proceeded via an intramolecular cyclization of the aroyllithium species, to give the tricyclic dienolate. Treatment of the tricyclic dienolate with electrophiles, such as alkyl halides, aldehydes, ketones, and epoxides gave the substituted oxazolo[2,3-a]isoindolinones in good yield. 相似文献
26.
Yoshio Hayakawa Eiji Hayashi Haruhiko Fukaya Naohiro Terasawa Takashi Abe Kota Omori Koichi Murai 《Liquid crystals》1996,20(3):367-371
Novel liquid crystals which have the perfluoropyrrolidino group, a heterocyclic perfluoroalkyl group, and which show smectic phases have been synthesized with perfluoro-(2-pyrrolidinopropionyl fluoride) as one of the starting materials. Analogues with a polymerizable functional group also have been prepared and polymerized to give side chain liquid crystal polymers. 相似文献
27.
Hideya Murai 《Liquid crystals》1993,15(5):627-642
Electro-optic properties of liquid crystal phase gratings (LCPGs), regarding groove depth, temperature and a cell gap, have been studied. The off response times are proportional to the square of the groove depth. The transmitted light colour depends on temperature. When there is a gap between the grating and the opposite substrate, their transmittance-voltage curve has a maximum and a minimum. The authors have also simulated the LCPG properties using a homogeneous alignment model. The simulating results coincide with experimental results; therefore the simulation method is considered useful to predict LCPG properties. 相似文献
28.
29.
Shigenori Kashimura Yoshiyuki Tane Yoshihiro Murai Tomohiro Nakai Ryuich Hirose 《Tetrahedron letters》2008,49(2):269-271
Reduction of dichlorosilanes with Mg metal in the presence of Lewis acid and LiCl was found to be the highly practical method for the synthesis of polysilanes. 相似文献