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51.
Atsushi Yashiro Dr. Yuya Tanaka Prof. Tomofumi Tada Prof. Shintaro Fujii Prof. Tomoaki Nishino Prof. Munetaka Akita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(37):9666-9673
In this work, the design, synthesis, and single-molecule conductance of ethynyl- and butadiynyl-ruthenium molecular wires with thioether anchor groups [RS=n-C6H13S, p-tert-Bu−C6H4S), trans-{RS−(C≡C)n}2Ru(dppe)2 (n=1 ( 1R ), 2 ( 2R ); dppe: 1,2-bis(diphenylphosphino)ethane) and trans-(n-C6H13S−C≡C)2Ru{P(OMe)3}4 3hex ] are reported. Scanning tunneling microscope break-junction study has revealed conductance of the organometallic molecular wires with the thioacetylene backbones higher than that of the related organometallic wires having arylethynylruthenium linkages with the sulfur anchor groups, trans-{p-MeS−C6H4-(C≡C)n}2Ru(phosphine)4 4 n (n=1, 2) and trans-(Th−C≡C)2Ru(phosphine)4 5 (Th=3-thienyl). It should be noted that the molecular junctions constructed from the butadiynyl wire 2R , trans-{ Au −RS−(C≡C)2}2Ru(dppe)2 ( Au : gold metal electrode), show conductance comparable to that of the covalently linked polyynyl wire with the similar molecular length, trans-{ Au −(C≡C)3}2Ru(dppe)2 63 . The DFT non-equilibrium Green's function (NEGF) study supports the highly conducting nature of the thioacetylene molecular wires through HOMO orbitals. 相似文献
52.
53.
Yanting Song Katsuya Takatsuki Muneki Isokawa Tetsushi Sekiguchi Jun Mizuno Takashi Funatsu Shuichi Shoji Makoto Tsunoda 《Analytical and bioanalytical chemistry》2013,405(25):7993-7999
In this study, a fast and quantitative determination method for branched-chain amino acids (BCAAs), namely leucine, isoleucine, and valine, was developed using a pillar array column. A pillar array column with low-dispersion turns was fabricated on a 20?×?20-mm2 microchip using multistep ultraviolet photolithography and deep reactive ion etching. The BCAAs were fluorescently labeled with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), followed by reversed-phase separation on the pillar array column. The NBD derivatives of the three BCAAs and an internal standard (6-aminocaproic acid) were separated in 100 s. The calibration curves for the NBD-BCAAs had good linearity in the range of 0.4–20 μM, using an internal standard. The intra- and interday precisions were found to be in the ranges of 1.42–3.80 and 2.74–6.97 %, respectively. The accuracies for the NBD-BCAA were from 90.2 to 99.1 %. The method was used for the analysis of sports drink and human plasma samples. The concentrations of BCAAs determined by the developed method showed good agreements with those determined using a conventional high-performance liquid chromatography system. As BCAAs are important biomarkers of some diseases, these results showed that the developed method could be a potential diagnostic tool in clinical research. 相似文献
54.
Unsymmetrical oxamides are conveniently synthesized in good yields by a new trapping reaction of unstable carbamoyl lithiums with isocyanates. 相似文献
55.
Sulfonylurea derivatives including useful antidiabetics (Tolbutamide, Chlorpropamide) were synthesized in good yields from benzene-sulfonamides with thiocarbamates in the presence of DBU. Thiocarbamates were prepared by the selenium-assisted carbonylation of primary amines with carbon monoxide, sulfur, and methyl iodide under mild conditions. 相似文献
56.
Novel chiral bisformamides have been prepared from (R,R)-1,2-cyclohexanediamine and utilized as Lewis bases in the asymmetric allylation of benzaldehyde with allyltrichlorosilane. The reaction in the presence of Lewis base 1i gave an 83:17 enantiomeric ratio (R/S) of the products in 90% isolated yield. 相似文献
57.
Yutaka Kubota Yuri Kaneda Kazuhiro Haraguchi Mirei Mizuno Hiroshi Abe Satoshi Shuto Takayuki Hamasaki Masanori Baba Hiromichi Tanaka 《Tetrahedron》2013
The key glycosyl donor for the target molecule 12 was prepared by two-step sequences; (1) acetalization of tert-butyldimethylsilyloxyacetaldehyde with 3-bromopropanediol, (2) DBN-initiated β-elimination of the resulting 2-(tert-butyldimethylsilyloxy)methyl-4-bromomethyl-1,3-dioxolane 11. Electrophilic glycosidation between 12 and silylated pyrimidine nucleobase proceeded efficiently to provide a mixture of β- and α-anomers of the respective glycosides 14 and 15. Tin radical-mediated reduction of the bromomethyl functional group of 14 and 15 gave protected 4′-C-methyl-dioxorane uracil- 16 and thymine nucleoside 17. The respective cytosine nucleoside 18 was synthesized from 16. De-silylation of 4′-methyl-1′,3′-dioxolane pyrimidine nucleosides 16–18 gave the target molecules. Evaluation of the anti-HIV-1 activity of the β- and α-anomers of the novel 4′-C-methyl-1′,3′-dioxolane nucleosides 22β,α–24β,α revealed that none of the nucleoside derivatives possess anti-viral activity against HIV-1 and show cytotoxicity against MT-4 cells at 100 μM. 相似文献
58.
The synthesis of glycosyl bromides from 1-O-acetyl sugars using a photo-irradiative phase-vanishing method involving molecular bromine was achieved. A bottom phase of molecular bromine was overlaid first with perfluorohexanes (FC-72), followed by overlaying with ethyl acetate containing a 1-O-acetyl sugar. Upon irradiation, the bromine layer gradually disappeared, leaving two phases. Glycosyl bromide was obtained in good yield from the ethyl acetate phase. 相似文献
59.
Prof. Dr. Hiromitsu Maeda Wataru Hane Dr. Yuya Bando Dr. Yoshitaka Terashima Dr. Yohei Haketa Hiroshi Shibaguchi Prof. Dr. Tsuyoshi Kawai Prof. Dr. Masanobu Naito Dr. Kazuto Takaishi Prof. Dr. Masanobu Uchiyama Dr. Atsuya Muranaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(48):16263-16271
Anion‐responsive π‐conjugated compounds having chiral alkyl chains were synthesized. Circular dichroism (CD) and circularly polarized luminescence (CPL) were observed in the solution‐state assemblies of the chiral anion receptors and those of their anion complexes as salts of a planar triazatriangulenium cation. The CD and CPL spectral patterns of the ion‐pair‐based assemblies were completely opposite to those of the anion‐free assemblies, and this suggests that anion binding and subsequent ion pairing change the chirality of the assembly modes. 相似文献
60.