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31.
Novel phosphonylation of the active Me group of pyridine derivatives is described.Reaction of 2 (and 4) -methylpyridine (3 and 5) with PCl5 in POCl3 gave 2 (and 4) -trichloromethylpyridine (4 and 6). Similarly, reaction of 4 (and 6) methyl-3-nitropyridine (7 and 9) afforded the corresponding trichloromethyl derivative (8 and 10). However, the similar reaction of 2-methyl-3-nitropyridine (11) gave dichloro-(3-nitro-2-pyridyl)-methylphosphonic dichloride (12).Mechanisms of the formation of these products are discussed. 相似文献
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Hydrothermal formation of tobermorite studied by in situ X‐ray diffraction under autoclave condition
Jun Kikuma Masamichi Tsunashima Tetsuji Ishikawa Shin‐ya Matsuno Akihiro Ogawa Kunio Matsui Masugu Sato 《Journal of synchrotron radiation》2009,16(5):683-686
Hydrothermal formation of tobermorite from a pre‐cured cake has been investigated by transmission X‐ray diffraction (XRD) using high‐energy X‐rays from a synchrotron radiation source in combination with a newly designed autoclave cell. The autoclave cell has a large and thin beryllium window for wide‐angle X‐ray diffraction; nevertheless, it withstands a steam pressure of more than 1.2 MPa, which enables in situ XRD measurements in a temperature range of 373 to 463 K under a saturated steam pressure. Formation and/or decomposition of several components has been successfully observed during 7.5 h of reaction time. From the intensity changes of the intermediate materials, namely non‐crystalline C–S–H and hydroxylellestadite, two pathways for tobermorite formation have been confirmed. Thus, the newly developed autoclave cell can be used for the analyses of reaction mechanisms under specific atmospheres and temperatures. 相似文献
34.
Porphyrin accumulation onto a self-assembled monolayer (SAM) of imidazole-substituted porphyrins by a supramolecular method to form a chain structure leads to significant increase of light absorption in the visible light region and therefore photocurrents. 相似文献
35.
In view of recent developments in the investigation on cuprate high- T(c) superconductors and the spin-Peierls compound CuGeO3, we study the effect of dilute impurity doping on the spin-Peierls state in quasi-one-dimensional systems. We identify a common origin for the emergence of antiferromagnetic order upon the introduction of static vacancies and superconductivity for mobile holes. 相似文献
36.
Hiroshi Tanaka Takeo Yoshioka Yasutaka Shimauchi Akihiro Yoshimoto Tomoyuki Ishikura Hiroshi Naganawa Tomio Takeuchi Hamao Umezawa 《Tetrahedron letters》1984,25(31):3351-3354
The tricyclic quinone 8 was successfully synthesized from naphthazalin, and the total synthesis of (±)-2-hydroxyaklavinone via 8 was accomplished in an overall yield of about 18% through the regio-controlled route. 相似文献
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Mayumi Tsutsui Tokuhiro Watanabe Akihiro Ohta Kayoko Takizawa 《Journal of heterocyclic chemistry》1980,17(4):809-812
1 H-Nmr spectra of cis and trans isomers of 2,3-, 2,5-, and 2,6-dimethylpiperazines were taken at various temperatures. The spectra of geometrical isomers bearing the ae or ea dimethyl groups showed broadening at lower temperatures. It was clarified that the measurement of the spectra at lower temperatures is useful for the discrimination of the geometrical isomers of dimethylpiperazines. 相似文献
40.
Atsushi Kikkawa Kunihiko Ohkubo Hideaki Satō Norihito Suzuki 《Optics Communications》1974,12(3):227-230
The time interval distribution of two successive photoelectric pulses depends not only upon the spectral linewidth but also on the correlation factor. The distribution is derived in the case of gaussian-lorentzian light under the condition of a markovian process and is also applied to the analysis of the counting loss of a circuit with dead time, from which information on the spectral linewidth is obtained. The theoretical counting loss is compared with the experimental one. 相似文献