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131.
Wood TE Ross AC Dalgleish ND Power ED Thompson A Chen X Okamoto Y 《The Journal of organic chemistry》2005,70(24):9967-9974
[structure: see text] A series of bis(dipyrromethene)s substituted with aromatic amide and aliphatic ester homochiral auxiliaries have been prepared and complexed with zinc(II) ions to form double-helical dinuclear complexes. CD analysis of the crude complexes revealed that the helicates formed in a diastereoselective manner. The helicates have been resolved into their constituent M and P helices by HPLC, indicating that the helical sense of the complexes is stable to racemization. 相似文献
132.
The rates of reactions of 5-dimethylamino-1-naphthalenesulphonyl chloride (dansyl chloride) with butylamine in organic solvents have been measured in the presence of polymer such as polyoxyethylene (POE) or polystyrene (PS) as cosolvent and compared with those in the presence of cosolvents of low molecular weight analogues, viz. diethyloxyethane (DEE) and toluene (Tol.). Acceleration by cosolvent POE, compared with DEE, increases with increasing volume fraction of cosolvent and the effect depends on the degree of polymerization of the polymer cosolvent. Similarly, addition of cosolvent PS to ethyl acetate or chloroform results in increase in the reaction rate as compared with cosolvent Tol. The effect by PS also showed dependence on the degree of polymerization. The effect of polymer cosolvent on chemical reactions between two low molecular weight species is explained in terms of the thermodynamics of polymer solutions. 相似文献
133.
M Fujita A Ota S Ito K Yamamoto Y Kawashima T Iso J Iwao 《Chemical & pharmaceutical bulletin》1990,38(4):936-941
SA2572 ((+)-1), 3-acetyl-2-[5-methoxy-2-[4-[N-methyl-N-(3,4,5-trimethoxyphenethyl) amino] butoxy]phenyl]-benzothiazoline hydrochloride is a newly synthesized Ca2+ antagonist having a inhibitory effect on the fast Na+ inward channel. In order to clarify the absolute configurations and the pharmacological properties of both enantiomers, compounds ((+)-1 and (-)-1) were synthesized. The configurations of these compounds were assigned on the basis of an X-ray crystallographic analysis of synthetic precursor (5). The in vitro Ca2+ channel blocking activities of (+)-1 and (-)-1 were evaluated in terms of the inhibitory activities on depolarization-induced contraction of guinea pig taenia cecum and rabbit aorta. The in vivo efficacy of the enantiomers was evaluated with their hypotensive effects in spontaneously hypertensive rats. Compound (-)-1 showed more potent Ca2+ antagonistic activities on guinea pig taenia cecum and rabbit aorta and the hypotensive effect than those activities of (+)-1. In the electrophysiological study of Langendorff perfused rabbit hearts, compound (+)-1 showed more potent inhibitory effect on the fast Na+ inward channel than that of compound (-)-1, and an approximately equal potent inhibitory effect on the slow Ca2+ inward channel as compared with compound (-)-1. Stereoselectivity of the pharmacological activity was found. 相似文献
134.
Structure of an alkaline hydrolysis product of heavenly blue anthocyanin was determined to be -4-0-(6-0-(-3-0-(β-D-glucopyranosyl)caffeyl)-β-D- glucopyranosyl)caffeic acid (). 相似文献
135.
2,3-Dihydroimidazo[1,5-α]pyridin-3-one (IV) was obtained by thermolysis of 2-pyridylacetyl azide (II) which was prepared from 2-pyridylacetohydrazide (I) on treatment with an equivalent mole of nitrous acid. Treatment of I with excess nitrous acid yielded α-oximino-α:-(2-pyridyl)-acetylazide (V). Thermal decomposition of V gave 3-(2-pyridyl)-1,2,4-4H-oxadiazolin-5-one (VII). 2-Cyanopyridine (IX) was obtained from V by the action of alkali. 2,3-Dihydroimidazo-[1,5-α ]pyridin-3-one (IV) was rearranged to VII upon treatment with nitrous acid. J. Chem. Soc., 14, 993 (1977) 相似文献
136.
Fukuzumi S Okamoto K Yoshida Y Imahori H Araki Y Ito O 《Journal of the American Chemical Society》2003,125(4):1007-1013
A ferrocene-quinone dyad (Fc-Q) with a rigid amide spacer and Fc-(Me)Q dyad, in which the amide proton acting as a hydrogen-bonding acceptor is replaced by the methyl group, are employed to examine the effects of hydrogen bonding on both the thermal and the photoinduced electron-transfer reactions. The hydrogen bonding of the semiquinone radical anion with the amide proton in Fc-Q(.-) produced by the electron-transfer reduction of Fc-Q is indicated by the significant positive shift of the one-electron reduction potential of Fc-Q. The hyperfine coupling constants of Fc-Q(.-) also indicate the existence of hydrogen bonding, agreeing with those predicted by the density functional calculation. The hydrogen-bonding dynamics in the photoinduced electron transfer from the ferrocene (Fc) to the quinone moiety (Q) in Fc-Q have been successfully detected in the femtosecond laser flash photolysis experiments. Thermal intramolecular electron transfer from Fc to Q in Fc-Q and Fc-(Me)Q also occurs efficiently in the presence of metal ions in acetonitrile at 298 K. The hydrogen bond formed between the semiquinone radical anion and the amide proton in Fc-Q results in remarkable acceleration of the rate of metal ion-promoted electron transfer as compared to the rate of Fc-(Me)Q in which hydrogen bonding is prohibited. The metal ion-promoted electron-transfer rates are well correlated with the binding energies of superoxide ion-metal ion complexes, which are derived from the g(zz) values of the ESR spectra. 相似文献
137.
Kohara T Koyama T Fujimura M Tanaka H Maeda J Fujimoto T Yamamoto I Arita M 《Chemical & pharmaceutical bulletin》2002,50(6):818-821
The oxidation behavior of Y-931, a potent atypical antipsychotic drug, was compared with that of clozapine and olanzapine. In two enzymatic systems (horseradish peroxidase (HRP)/glutathione (GSH) and HRP/H(2)O(2)/GSH) which generate thiyl radicals, clozapine markedly strengthened the electron paramagnetic resonance (EPR) signal for the radical. Olanzapine, Y-931 and the major metabolites (compounds 1-3) had no or minimal effect on the intensity of this signal. In addition, the redox potential values for the three derivatives were in accord with the EPR spin trapping results. In toxicological experiments in human leukocytes, a concentration-dependent toxicity was observed when neutrophils were incubated with clozapine (1-10 micromol/l) and H(2)O(2) (1 mmol/l). However, Y-931 and olanzapine did not show remarkable toxicity under the conditions. 相似文献
138.
Takeshi Suwa Terutaka Watanabe Jiro Okamoto Sueo Machi 《Journal of polymer science. Part A, Polymer chemistry》1979,17(1):129-138
Simultaneous formation of hydrofluoric acid (HF) in the radiation-induced polymerization of tetrafluoroethylene (TFE) was investigated. HF concentration in PTFE latex was determined mainly by conductometric titration with 0.01 and 0.001N NaOH. The amount of HF formed is almost independent of agitation speed and the amount of n-hexadecane added and is maximal at ca. 70°C corresponding to the rate of polymerization. The rate of HF formation increases with the initial pressure of TFE monomer and dose rate and decreases with polymerization or TFE consumption. This fact suggests that HF is formed mainly by TFE reactions and not by the degradation of PTFE. The mechanism of HF formation in this reaction system in the absence of oxygen is shown in the following two schemes: scheme I is the reaction of TFE with primary radicals (OH·, H·, e) from the radiolysis of water; scheme II is the reaction of water with the species from the radiolysis of TFE. On the assumption that HF is formed only according to scheme I, the G value of HF formation G(HF)calc can be calculated as 11.25. All observed G values G(HF)obs are larger than G(HF)calc. When the polymerization is carried out at 20 kg/cm2 under various dose rates, G(HF)obs increases with the dose rate. When the polymerization is carried out at 3.0 × 104 rad/hr under various pressures, G(HF)obs decreases with the decrease in pressure from 20 to 2 kg/cm2 and is fairly close to G(HG)calc at 2 kg/cm2. This indicates that HF formation is due mainly to scheme II at high pressure (in the presence of enough TFE) and to scheme I as the pressure is lowered. 相似文献
139.
Ken-Ichi Okamoto Kazuhiro Tanaka Michiaki Muraoka Hidetoshi Kita Yutaka Maruyama 《Journal of Polymer Science.Polymer Physics》1992,30(11):1215-1221
Gas permeability and permselectivity are investigated for polybenzoxazoles from bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane (BAHHP) and aromatic diacid chlorides. Effects of thermal cyclization on the permeation properties are also investigated. The polybenzoxazole from BAHHP and 4,4′-(1,1,1,3,3,3-hexafluoroisopropylidene)dibenzoyl chloride (HFDB) displays high performance for CO2/CH4 separation ( $ {\rm P}_{{\rm CO}_2 } $ = 6.1 × 10?9 cm3 (STP) cm?1 s?1 cm-Hg?1, and $ {{{\rm P}_{{\rm CO}_2 } } \mathord{\left/ {\vphantom {{{\rm P}_{{\rm CO}_2 } } {{\rm P}_{{\rm CH}_4 } }}} \right. \kern-\nulldelimiterspace} {{\rm P}_{{\rm CH}_4 } }} $ = 38 at 35°C). The polybenzoxazole from BAHHP and 2,6-naphthalene dicarbonyl chloride displays high performance for H2/CO or H2/CH4 separation ( $ {\rm P}_{{\rm H}_2 } $ = 2.4 × 10?9 cm3 (STP) cm?1 s?1 cm-Hg?1, $ {{{\rm P}_{{\rm H}_2 } } \mathord{\left/ {\vphantom {{{\rm P}_{{\rm H}_2 } } {{\rm P}_{{\rm CO}} }}} \right. \kern-\nulldelimiterspace} {{\rm P}_{{\rm CO}} }} $ = 71, and $ {{{\rm P}_{{\rm H}_2 } } \mathord{\left/ {\vphantom {{{\rm P}_{{\rm H}_2 } } {{\rm P}_{{\rm CH}_{\rm 4} } }}} \right. \kern-\nulldelimiterspace} {{\rm P}_{{\rm CH}_{\rm 4} } }} $ = 250). Permeation properties for the polybenzoxazole from BAHHP and HFDB are close to those for a polyimide of similar chemical structure. The permeation properties are discussed in connection with packing density and local segmental mobility. © 1992 John Wiley & Sons, Inc. 相似文献
140.
The hydrosilylation of α,β-unsaturated nitriles and esters such as acrylonitrile, crotononitrile, cinnamonitrile, ethyl and methyl acrylate, ethyl and methyl crotonate and ethyl and methyl methacrylate using tris(triphenylphosphine)chlororhodium as a catalyst is described. The hydrosilylation of α,β-unsaturated nitriles provided α-adduct exclusively in high yield except in the case of trichlorosilane which afforded β-adduct with acrylonitrile. On the other hand, the hydrosilylation of α,β-unsaturated esters gave rather complex results. The selectivity of the reactions was dramatically affected by the substituent of the ester group and that on the β-carbon. Thus, the hydrosilylation of ethyl acrylate with triethylsilane afforded a β-adduct, but, that of ethyl crotonate using the same hydrosilane gave a 1,4-adduct exclusively. Possible mechanisms for these reactions are discussed. 相似文献