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131.
Kazuhiro Fukumori Yoshikatsu Akiyama Yoshikazu Kumashiro Jun Kobayashi Masayuki Yamato Kiyotaka Sakai Teruo Okano 《Macromolecular bioscience》2010,10(10):1117-1129
Ultra thin poly(N‐isopropylacrylamide) (PIPAAm) modified glass coverslips (PIAPAm‐CS) using electron beam irradiation exhibited a clear relationship between the polymer thickness and thermal cell adhesion/detachment behavior. The polymer thickness dependency and the characteristic of ultra thin PIPAAm layer, has been illustrated in terms of the molecular motion of the modified PIPAAm chains. PIPAAm‐CSs surfaces with various area‐polymer densities and thicknesses were characterized by AFM and protein adsorption assay. The newly obtained results gave a further insight into the illustration. Finally, the future application of intelligent surfaces was discussed for fabricating tissue and organ.
132.
133.
Kazuhiro Haraguchi Kiju Konno Kaori Yamada Yasuyuki Kitagawa Kazuo T. Nakamura Hiromichi Tanaka 《Tetrahedron》2010,66(25):4587-8669
Stereoselectivity in N-iodosuccimide (NIS)-mediated electrophilic glycosidation was examined by employing 2,4-bis-O-(trimethylsilyl)thymine and three different silyl-protected erythro-furanoid glycals 12, 16, and 18. As a result, it was found that 3,5-O-(di-t-butylsilylene)-protected 18 gave only the β-anomer (21). The remarkable stereoselectivity observed by employing 18 is discussed on the basis of its X-ray crystallographic analysis. 1-Substituted glycals gave the corresponding β-anomer, again exclusively, to provide access to 1′-branched 2′-deoxynucleosides. 相似文献
134.
Kobayashi S Waki T Nakanishi I Matsumoto K Anzai K 《Chemical & pharmaceutical bulletin》2010,58(11):1442-1446
New potent antioxidants conjugating the catechol (=pyrocatechol; pyrCat) group to two N-termini of modified double-stranded tyrosine residues were synthesized and showed radical scavenging activity with 2,2-diphenyl-1-picrylhydrazyl radical (DPPH radical, DPPH˙) as a free radical model, second-order rate constants for the DPPH˙ scavenging reaction, and the results from electron spin resonance (ESR) studies. It was found that the tyrosine (Tyr) residue and pyrCat containing new antioxidants developed in the study have about 3-20 times more potent antioxidative activity than Trolox, pyrCat, and L-ascorbic acid (VC). In order to elucidate the relationship between antioxidant activity and the molecular orbital states, and to design potent antioxidants we present an interesting approach using an absolute hardness (η)-absolute electronegativity (χ) diagram based on chemical hardness. It was shown that quantum chemicals were required to develop potent antioxidants. 相似文献
135.
We show that the mono-N-methylated and -ethylated derivatives of the achiral compound bisguanidinobenzene undergo spontaneous asymmetric crystallization into a chiral form with chiral space group P212121. The absolute configurations of the chiral crystals were determined by X-ray crystallography and correlated with circular dichroism (CD) spectra recorded in the solid state. The corresponding protonated and isopropylated derivatives, by contrast, afforded achiral crystals. 相似文献
136.
Yamaji M Ogasawara M Kikuchi K Nakajima S Tero-Kubota S Marciniak B Nozaki K 《Physical chemistry chemical physics : PCCP》2007,9(25):3268-3275
Photochemical profiles of omega-cleavage of carbon-X (X = Br and Cl) bonds in m-bromo- and m-chloromethylbenzophenones (m-BMBP and m-CMBP) were investigated by laser photolysis techniques and DFT calculations. m-BMBP and m-CMBP were found to undergo omega-bond cleavage to yield the m-benzoylbenzyl radical (m-BBR) at 295 K, and the quantum yields were determined. No CIDEP signal was detected upon 308 nm laser photolysis of both the compounds. From these observations, it was inferred that the omega-bond of these m-halomethylbenzophenones (m-HMBP) cleaves in the lowest excited singlet state (S(1)(n,pi(*))) upon direct excitation. Upon triplet sensitization of acetone (Ac), the m-BBR formation was observed in transient absorption for an Ac-m-BMBP system, and an efficiency of the C-Br bond cleavage in the lowest triplet state (T(1)(n,pi(*))) of m-BMBP was determined. In contrast, formation of triplet m-CMBP was seen for an Ac-m-CMBP system. Absence of C-Cl bond cleavage in the triplet state of m-CMBP indicated the reactive state of m-CMBP for omega-cleavage is only the S(1)(n,pi(*)) state. Based on the efficiencies and DFT calculations for excited state energies, photoinduced omega-bond dissociation of m- and p-HMBPs was characterized. 相似文献
137.
138.
Nakanishi W Nakamoto T Hayashi S Sasamori T Tokitoh N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(1):255-268
To clarify the nature of five-center, six-electron (5c-6e) C(2)Z(2)O interactions, atoms-in-molecules (AIM) analysis has been applied to an anthraquinone, 1,8-(MeZ)(2)ATQ (1 (Z=Se), 2 (Z=S), and 3 (Z=O)), and a 9-methoxyanthracene system, 9-MeO-1,8-(MeZ)(2)ATC (4 (Z=Se), 5 (Z=S), and 6 (Z=O)), as well as 1-(MeZ)ATQ (7 (Z=Se), 8 (Z=S), and 9 (Z=O)) and 9-MeO-1-(MeZ)ATC (10 (Z=Se), 11 (Z=S), and 12 (Z=O)). The total electronic energy density (H(b)(r(c))) at the bond critical points (BCPs), an appropriate index for weak interactions, has been examined for 5c-6e C(2)Z(2)O and 3c-4e CZO interactions of the n(p)(O)sigma*(Z--C) type in 1-12. Some hydrogen-bonded adducts were also re-examined for convenience of comparison. The total electronic energy densities varied in the following order: OO (3: H(b)(r(c))=0.0028 au)=OO (6: 0.0028 au)>OO (9: 0.0025 au)> or =NNHF (0.0024 au)> or =OO (12: 0.0023 au)>H(2)OHOH (0.0015 au)>SO (8: 0.0013 au)=SO (2: 0.0013 au)> or =SO (11: 0.0012 au)=SO (5: 0.0012 au)>HFHF (0.0008 au)=SeO (10: 0.0008 au)=SeO (4: 0.0008 au)> or =SeO (1: 0.0007 au)> or =SeO (7: 0.0006 au)>HCNHF (-0.0013 au). H(b)(r(c)) values for SO were predicted to be smaller than the hydrogen bond of H(2)OHOH and H(b)(r(c)) values for SeO are very close to or slightly smaller than that for HFHF in both the ATQ and 9-MeOATC systems. In the case of Z=Se and S, H(b)(r(c)) values for 5c-6e C(2)Z(2)O interactions are essentially equal to those for 3c-4e CZO if Z is the same. The results demonstrate that two n(p)(O)sigma*(Z--C) 3c-4e interactions effectively connect through the central n(p)(O) orbital to form the extended hypervalent 5c-6e system of the sigma*(C--Z)n(p)(O)sigma*(Z--C) type for Z=Se and S in both systems. Natural bond orbital (NBO) analysis revealed that n(s)(O) also contributes to some extent. The electron charge densities at the BCPs, NBO analysis, and the total energies calculated for 1-12, together with the structural changes in the PhSe derivatives, support the above discussion. 相似文献
139.
Kenjiro Hattori Tomoko Takeuchi Mika Ogata Ayumi Takanohashi Katsuhiko Mikuni Katsuyoshi Nakanishi Hideo Imata 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):339-342
We obtained the association constants Ka of estrogen (E2) and environmental chemicals by the surface plasmon resonance (SPR) assay using the immobilized mono-6-O-α-maltosyl-β-CD (G2βCD) compared with the immobilized β-CD and the immobilized estrogen receptor (ER). The association behavior of G2βCD was shown as a ER model compound. The calibration curve was determined by the initial rate of association depending on
the various concentrations, and the minimum detectable concentrations in the order of parts per billion were calculated. The
SPR assay has advantages that the pre-treatment of the sample is not necessary and the immobilized ligand is stable and useful
for the repeated measurement. 相似文献
140.
Kazuhiro Kobayashi Yasutoshi Himei Shuhei Fukamachi Miyuki Tanmatsu Osamu Morikawa Hisatoshi Konishi 《Tetrahedron》2007,63(20):4356-4359
Heating mixtures of 2-(pyrrol-1-yl)benzaldehydes and aryl amines under argon afforded 9-arylamino-9H-pyrrolo[1,2-a]indoles, via cyclization of the resulting 2-(pyrrol-1-yl)benzaldimine intermediates. Heating in the presence of oxygen afforded (Z)-9-arylimino-9H-pyrrolo[1,2-a]indoles, which were successfully hydrolyzed with hydrochloric acid to give pyrrolo[1,2-a]indol-9-ones. 相似文献