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11.
Mikio Hori Tadashi Kataoka Hiroshi Shimizu Akihiko Tomoto 《Tetrahedron letters》1981,22(37):3629-3632
1-Benzoyl-2-methy1-3,4-dihydro-2-thianaphthalene () underwent novel intermolecular 1,4-rearrangement in refluxing toluene to give an enol ether , while rearrangement of 2-phenyl derivative proceeded intramolecularly in refluxing xylene to afford a 1,4-rearranged enol ether . On the other hand, ylides were refluxed in alcohols to afford some ring-opened products . 相似文献
12.
Rijssenbeek JT Saito T Malo S Azuma M Takano M Poeppelmeier KR 《Journal of the American Chemical Society》2005,127(2):675-681
The related parameters of cation size and valence that control the crystallization of Sr(3)CaRu(2)O(9) into a 1:2 B-site-ordered perovskite structure were explored by cationic substitution at the strontium and calcium sites and by the application of high pressure. At ambient pressures, Sr(3)MRu(2)O(9) stoichiometries yield multiphasic mixtures for M = Ni(2+), Mg(2+), and Y(3+), whereas pseudocubic perovskites result for M = Cu(2+) and Zn(2+). For A-site substitutions, an ordered perovskite structure results for Sr(3-x)Ca(x)CaRu(2)O(9), with 0 = x = 1.5. In contrast, Ba(2+) substitution for Sr(2+) is accompanied by a phase change to a hexagonal BaTiO(3) structure type. At high pressures and temperatures, a 1:2 B-site-ordered perovskite structure is stabilized for Sr(3-x)Ba(x)CaRu(2)O(9), with 0 = x = 3. The scarcity of B-site-ordered perovskite ruthenates at ambient pressure and the metastable nature of the high-pressure phases underscore the strict size and valence requirements that must be met by the constituent cations to achieve these uncommon ordered structures. 相似文献
13.
Carmenza Duque Masuo Morisaki Nobuo Ikekawa Mikio Shikita 《Tetrahedron letters》1979,20(46):4479-4482
Cholesterol and 20-hydroxycholesterol labelled at C-22 stereospecifically by deuterium were incubated with the enzyme of bovine adrenocortical mitochondria. The results indicated that hydroxylation occurs with retention of the configuration of C-22 to give exclusively the 22R stereoisomers of 22-hydroxy- and/or 20,22-dihydroxycholesterol. 相似文献
14.
Mitamura K Setaka M Shimada K Honma S Namiki M Koh E Mizokami A 《Biomedical chromatography : BMC》2005,19(10):796-801
A promising liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) for analysis of the sulfates of 5alpha-androgen, androsterone and epiandrosterone (A-S and EpiA-S) in human serum was developed. The method was used to assess one of the markers of 5alpha-reductase activity of males including patients with prostate cancer (PC). After deproteinization with acetonitrile, the androgen sulfates and the internal standard, [7,7,16,16-2H4]dehydroepiandrosterone-S, were extracted from human serum using a solid-phase extraction cartridge and washed with hexane. The extract was reconstituted and applied to the LC/ESI-MS system operated in the selected ion monitoring mode. The method was validated over the range 0.02-5 microg/mL (A-S) and 0.005-1.5 microg/mL (EpiA-S) using 10 microL of human serum. The method was a concise procedure without chemical or enzymatic hydrolysis of the conjugates, purification by high-performance liquid chromatography and/or derivatization, and proved to be satisfactory in its reproducibility and accuracy. The levels of these androgen sulfates tended to decrease during aging, and the A-S levels in the sera obtained from both healthy males and patients with PC were correlated with their EpiA-S levels. 相似文献
15.
Hossain MJ Yamasaki M Mikuriya M Kuribayashi A Sakiyama H 《Inorganic chemistry》2002,41(15):4058-4062
A new end-off type acyclic ligand with four hydroxyethyl arms, 2,6-bis[bis(2-hydroxyethyl)aminomethyl]-4-methylphenol [H(bhmp)], formed dinuclear cobalt(II) complexes [Co(2)(bhmp)(OAc)(2)]BPh(4) (1) and [Co(2)(bhmp)(OBz)(2)]BPh(4) (2). The complex 1.2.5CH(3)CN (C(50)H(62.5)BCo(2)N(4.5)O(9)) crystallizes in the monoclinic space group C2/c with dimensions a = 25.424(5) A, b = 13.376(2) A, c = 29.913(6) A, beta = 105.930(3) degrees, and V = 9781(3) A(3) and with Z = 8. X-ray diffraction analysis revealed a mu-phenoxo-bis(mu-acetato)dicobalt(II) core structure containing two octahedral cobalt(II) ions. Electronic spectra were investigated for 1 and 2 in the range 400-1800 nm, and the data were typical for the octahedral high-spin cobalt(II) complexes. Magnetic susceptibility was measured for 1 and 2 over the temperature range 4.5-300 K, and the data were analyzed well using our theoretical method. The best fitting parameters were kappa = 0.77, lambda = -116 cm(-1), Delta = 572 cm(-1), and J = -0.44 cm(-1) for complex 1 and kappa = 0.96, lambda = -93 cm(-1), Delta = 616 cm(-1), and J = -0.33 cm(-1) for complex 2. 相似文献
16.
The fifth overtones of the C-H stretching vibrations of pyridine, pyrazine, thiophene, 3-methylthiophene, furan and pyrrole in the liquid state have been observed by a thermal lens technique. It was found that their frequency shifts from that of benzene are proportional to the decrease in the relevant C-H bond length. 相似文献
17.
Synthesis and inversion barriers of undeca- and dodeca-substituted saddle shaped porphyrin complexes
Synthesis and barriers to inversion of a series of highly saddle shaped complexes are reported. The ΔG≠ has decreased by 8 kJ mol−1 at 243 K when the meso phenyl groups are replaced by bulkier 2,6-dichlorophenyl groups, and by 17 kJ mol−1 when one of the peripheral ethyl groups is removed. 相似文献
18.
A nanosecond laser photolysis study was carried out for the Cr(III) porphyrin complexes of 2,3,7,8,12,13,17,18-octaethylporphyrin, [Cr(OEP)(Cl)(L)], and of 5,10,15,20-tetramesitylporphyrin, [Cr(TMP)(Cl)(L)], in toluene containing water and an excess amount of L (L = axial ligand). The laser photolysis generates the triplet excited state of the parent complex as well as a five-coordinate complex, [Cr(porphyrin)(Cl)], produced by the photodissociation of the axial ligand L. The yields for the formation of the triplet state and the photodissociation of L are found to markedly depend on the nature of both L and porphyrin ligand. The five-coordinate [Cr(porphyrin)(Cl)] readily reacts with both H(2)O and L in the bulk solution to give [Cr(porphyrin)(Cl)(H(2)O)] and [Cr(porphyrin)(Cl)(L)], respectively. The axial H(2)O ligand in [Cr(porphyrin)(Cl)(H(2)O)] is then substituted by the ligand L to regenerate the original complex [Cr(porphyrin)(Cl)(L)]. In principle, the substitution reaction takes place by the dissociative mechanism: the first step is the dissociation of H(2)O from [Cr(porphyrin)(Cl)(H(2)O)], followed by the reaction of the five-coordinate [Cr(porphyrin)(Cl)] with the ligand L to regenerate [Cr(porphyrin)(Cl)(L)]. The rate constants for this ligand substitution reaction are found to exhibit bell-shaped ligand concentration dependence. The detailed kinetic analysis revealed that both ligands L and H(2)O in toluene make a hydrogen bond with the axial H(2)O ligand in [Cr(porphyrin)(Cl)(H(2)O)] to yield dead-end complexes for the substitution reaction. The reaction mechanisms are discussed on the basis of the substituent effects of the porphyrin peripheral groups and the kinetic parameters determined from the temperature dependence of the rate constants. 相似文献
19.
20.
Mikio Ohno Keiichi Ohno Junkichi Sohma 《Journal of polymer science. Part A, Polymer chemistry》1987,25(5):1273-1284
Plasma-polymerized methyl methacrylate (PPMMA) film was produced by a radio-frequency glow discharge of methyl methacrylate (MMA) gas with argon. PPMMA deposited under a plasma of mild energy was separated into a soluble fraction (sol-PPMMA) and an insoluble matrix (insol-PPMMA), which is highly crosslinked, by solvent-extraction and filtration. The chemical structure of the sol-PPMMA was determined by pyrolysis/gas chromatography, IR spectroscopy, 1H-NMR, 13C-NMR, and elemental analysis techniques. On the other hand, the structure of the insol-PPMMA was examined with IR spectroscopy, 13C-NMR with CP/MAS method, and elemental analysis. The crosslinking mechanism in the plasma polymerization of MMA is discussed on the basis of product analyses of the sol-PPMMA and the insol-PPMMA. 相似文献