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941.
Michieletti M Bracci A Compostella F De Libero G Mori L Fallarini S Lombardi G Panza L 《The Journal of organic chemistry》2008,73(22):9192-9195
A new practical synthesis of alpha-GalCer and of its analogues is presented, opening the chance to easily modify the sphingosine chain. The common precursor is a disaccharide, obtained by coupling tetra-O-benzyl-D-galactose with allyl 2,3-O-isopropylidene-D-lyxofuranoside. Introduction of alkyl chains via Wittig reaction (for alpha-GalCer and OCH) or via Williamson reaction (for oxa analogues) followed by standard synthetic steps allows one to efficiently obtain such compounds. The analogues are able to activate iNKT cells when presented by CD1d expressing cells. 相似文献
942.
943.
Yasunori Yamada Daishin Koori Kengo Mori Yuuki Oshikawa 《Journal of Coordination Chemistry》2016,69(24):3735-3744
The reaction of N,N′-bis(2-hydroxybenzyl)-N,N′-bis(2-pyridylmethyl)-R-1,2-propanediamine (R-bbppnH2) with LnCl3?6H2O (Ln: Lu, Yb) stereoselectively gave an optically active complex, [LnCl(R-bbppn)], which crystallizes in the acentric space group of P212121. The central lutetium(III) is coordinated by two oxygens from two phenolates, four nitrogens from two pyridines, and one bidentate propanediamine of R-bbppn2?, one chloride to form a seven-coordinate distorted pentagonal bipyramidal geometry. Although two optical isomers, ΔΛΔ and ΛΔΛ, are possible for such a structure, the absolute configuration of the complex is stereoselectively unified to ΔΛΔ. The coordinated chloride of the complex is readily replaced by other ligands, and hence the reaction with thiocyanate results in formation of another seven-coordinate complex, [Ln(NCS)(R-bbppn)]. 相似文献
944.
Aromaticity Reversal in the Lowest Excited Triplet State of Archetypical Möbius Heteroannulenic Systems
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Juwon Oh Dr. Young Mo Sung Woojae Kim Dr. Shigeki Mori Prof. Dr. Atsuhiro Osuka Prof. Dr. Dongho Kim 《Angewandte Chemie (International ed. in English)》2016,55(22):6487-6491
The aromaticity reversal in the lowest triplet state (T1) of a comparable set of Hückel/Möbius aromatic metalated expanded porphyrins was explored by optical spectroscopy and quantum calculations. In the absorption spectra, the T1 states of the Möbius aromatic species showed broad, weak, and ill‐defined spectral features with small extinction coefficients, which is in line with typical antiaromatic expanded porphyrins. In combination with quantum calculations, these results indicate that the Möbius aromatic nature of the S0 state is reversed to Möbius antiaromaticity in the T1 state. This is the first experimental observation of aromaticity reversal in the T1 state of Möbius aromatic molecules. 相似文献
945.
Kanai A Takeda Y Kuramochi K Nakazaki A Kobayashi S 《Chemical & pharmaceutical bulletin》2007,55(3):495-499
The synthesis of the key intermediate (4) in the proposed route to D8646-2-6 is described. The aldol reaction of the carbohydrate-containing pyrone 7 with the aldehyde 6 was accomplished by using LiHMDS and Sc(OTf)3 or Sn(OTf)2. The stepwise dehydration reaction of the aldol adduct 14, followed by Stille coupling with vinyl stannane 5 which contained phosphonate gave the desired 4. 相似文献
946.
Suzuki T Horie Y Koike K Satake M Oshima Y Iwataki M Yoshimatsu S 《Journal of chromatography. A》2007,1142(2):172-177
Several strains of Protoceratium reticulatum, one of the dinoflagellates producing yessotoxins (YTXs), were collected from various shellfish producing areas in Japan. YTXs in the cultured strains were analyzed by liquid chromatography-mass spectrometry (LC-MS). Neutral loss scan monitoring, multiple reaction monitoring (MRM) for more than 20 YTX analogues, and full-scan MS/MS spectra obtained with a hybrid triple quadrupole/linear ion trap mass spectrometer showed that yessotoxin (YTX), 45,46,47-trinoryessotoxin (trinorYTX), 1-homoyessotoxin (homoYTX), and 45,46,47-trinor-1-homoyessotoxin (trinor-1-homoYTX) were the dominant toxins in these strains of P. reticulatum. Enone isomer of 42,43,44,45,46,47,55-heptanor-41-oxoyessotoxin (noroxoYTX enone) was also detected in some strains. Toxin profiles and contents were different among the strains. Some strains produced YTX, trinorYTX, 1-homoYTX, trinor-1-homoYTX, and noroxoYTX enone, whereas other strains produced only YTX or 1-homoYTX. This is the first identification of 1-homoYTX and noroxoYTX enone in P. reticulutum in Japan. Some strains did not produce any detectable YTX analogues. 相似文献
947.
Kang JH Katayama Y Han A Shigaki S Oishi J Kawamura K Toita R Han XM Mori T Niidome T 《Journal of the American Society for Mass Spectrometry》2007,18(1):106-112
A novel mass spectrometry-based assay system for determining protein kinase activity employing mass-tagged substrate peptide probes was used for the diagnosis of tumors. Two peptide probes (H-type and D-type) were synthesized containing the same substrate peptide sequence for protein kinase C (PKC). The molecular weights of the two probes differ because of the incorporation of deuterium into the acetyl groups of the D-type probe. The lysates of the normal and tumor tissue were prepared and reacted with the H- and D-type peptide probes, respectively. The PKC activities of the normal and tumor tissues can be compared simply and directly by calculating the phosphorylated ratio to each peptide probe, obtained from the peak intensity of the mass spectrum after mixing of the two reaction solutions. The phosphorylation ratio for the reaction of the H-type peptide probe with the tumor tissue lysate (B16 melanoma) was more than three times higher than that of the D type peptide probe with the normal skin tissue lysate. These results show that the novel assay system for detecting protein kinase activity using mass-tag technology can be a simple and useful means to profile protein kinase activity for cell or tissue lysate samples, and can be applied to the diagnosis of tumors. 相似文献
948.
Kanaya K Tada S Mori B Takahashi R Ikegami S Kurasawa S Okuzaki M Mori Y Innami S 《Journal of AOAC International》2007,90(1):225-237
A preliminary interlaboratory study was conducted to evaluate the validity of the modified AOAC method for determination of total dietary fiber by Tada and Innami, in which the 3-step enzymatic digestion process in AOAC Method 991.43 is modified to a 2-step process without pH adjustment. Total dietary fiber contents in 8 representative foodstuffs were measured using both the original AOAC Method 991.43 and the modified method in 6 research facilities in Japan. Repeatability relative standard deviations, reproducibility relative standard deviations, and Horwitz ratio values from the modified method were equivalent to those from AOAC Method 991.43, except in the rice sample. However, this exceptional case shown in the modified method was entirely dissolved by the addition of alpha-amylase stabilizing agents. The modified method, which shortens the process of enzymatic digestion from 3 to 2 steps and in which only reaction temperature is adjusted under the same pH, was found not only to give accurate values comparable to the original method, but also to substantially reduce the labor required by the laboratory staff in the process of routine analysis. This study revealed that the validity of the modified method was further ensured by adding alpha-amylase stabilizing agents to the reaction system. 相似文献
949.
Itou Y Mori S Udagawa T Tachikawa M Ishimoto T Nagashima U 《The journal of physical chemistry. A》2007,111(2):261-267
The geometric and kinetic isotope effects (GIE and KIE) for thermal [1,5]-sigmatropic H and D shifts of (Z)-1,3-pentadiene were studied by including the direct quantum effect of the migrating H or D nucleus in the multi-component molecular orbital-Hartree-Fock (MC_MO-HF) method. Based on the results, the C(1)-D bond lengths are 0.007 Angstrom shorter than the C1-H bond lengths in both the reactant (A) and the transition states (TS), whereas other bond lengths resemble those between H and D. The ratio of the rate constant (k(H)/k(D)) of the reaction for the thermal [1,5]-H and D shifts determined using the MC_MO-HF method (8.28) is closer to the experimental value (12.2) than that determined using either the conventional restricted Hartree-Fock (4.10) or restricted M?ller-Plesset second-order perturbation (3.79) methods. 相似文献
950.
Addition of the silylated tag (STag) enables peptides to be highly soluble in CPME, allowing them to be used at high concentrations in a coupling reaction to enhance reactivity and achieve effective synthesis of sterically hindered peptides. We described the development of a continuous one-pot STag-assisted peptide synthesis platform as a method that provides near-stoichiometric, speedy, environmentally friendly, and scalable peptide synthesis. 相似文献