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991.
The development of efficient methods for the indole synthesis catalyzed by Cu(II) salts and its applications were investigated. Cu(OAc)(2) has been proved to be the best catalyst for the synthesis of various 1-p-tolylsulfonyl or 1-methylsulfonylindoles, which have both electron-withdrawing and electron-donating groups on the aromatic ring and C2 position of indoles. For the primary aniline derivatives, Cu(OCOCF(3))(2) showed good activities, while Cu(OAc)(2) was a good catalyst for the cyclization of secondary anilines. This methodology could be applied to the sequential cyclization reaction for the compounds which have the electrophilic part in the same molecule. By prior treatment with KH, the sequential cyclization was realized to provide the tricyclic ring systems, but it was limited to five- and six-membered rings for the second cyclization. Finally, formal and total synthesis of hippadine with the Cu(II)-promoted indole synthesis as the key step was accomplished. 相似文献
992.
Toshikatsu Koga Akihiro Hirashima Yuji Ueda Mutsuo Morita 《Theoretical chemistry accounts》1982,62(1):55-67
For a one-electron homonuclear diatomic system with arbitrary nuclear charge Z, the change in the nature of diatomic interaction and its density origin are quantitatively examined as a function of Z by the method of binding/antibinding analyses based on the Hellmann-Feynman theorem. In the Isg ground state, two energy extrema, potential barrier at a large internuclear distance and potential minimum at a smaller distance, appear for 1<Z<1.44. The binding part of the partitioned Hellmann-Feynman forces suffers little effect of Z, and these two extrema are attributed respectively to the increase in the nuclear repulsion and to the decrease in the antibinding part of the partitioned forces. In the antibonding 2pu state, a stable molecule is formed for Z<1. This appearance of the bonding nature is shown to have its origin in the binding part which is almost unchanged by the decrease of Z. 相似文献
993.
994.
Takushi Kurihara Yasuhiko Sakamoto Toshio Kobayashi Masanobu Mori 《Journal of heterocyclic chemistry》1978,15(5):737-743
Extensive studies of the Knoevenagel condensation of aromatic aldehydes and active methyl-lene compounds have been reported (2). In 1894, Knoevenagel reported (3) the reaction of benz-aldehyde with ethyl benzoylpyruvate in the presence of piperidine to give ehtyl benzyl-(bis-benzoyl)pyruvate, m.p. 162°, but no yield of the product was reported. This paper deals with the interesting results of the reactions of ethyl acetylpyruvate ( 2 ) ( 4 ) and ethyl benzoylpyruvate ( 3 ) (5) with some aromatic aldehydes ( 1a-f ). 相似文献
995.
The radiation absorbed dose was estimated for 131I therapy of metastatic lesions of thyroid cancer, by the quantitative gamma-camera imaging. Uptake for eleven lesions in five cases (out of four patients) was measured for two times after 131I administration. Activities were calculated from opposed images with corrections for distance and depth using empirical formulae. An activity time curve was assumed as a reminder of two exponentials and fitted to measured values. The sizes of lesions were evaluated using the multi-slice CT images. An increase of frequency of activity measurement, particularly within a few days after 131I administration is desirable, for the purpose of an improvement of accuracy of dosimetry. 相似文献
996.
K. Sakamoto N. Aota Y. Miyamoto S. Kosanda Y. Oura T. Okui M. Igarashi T. Nakanishi 《Journal of Radioanalytical and Nuclear Chemistry》1997,215(1):69-76
Fifteen GSJ (Geological Survey of Japan) and six KIER (Korean Institute of Energy and Resources; now Korean Institute of Geology, Mining and Materials, KIGAM) igneous rock series and nine GSJ sedimentary rock series reference samples were analysed for 21–29 elements by neutron and/or photon activation analysis (NAA and PAA); 14 MeV-NAA for Si and Al, fission track method for U, radiochemical and instrumental NAA for rare earth elements, with reactor neutrons for the latter two. Instrumental neutron and photon AA for the remaining elements were performed with reactor neutrons and bremsstrahlung of end-point energy of 30 MeV, respectively. The reactor irradiations were performed at core sites and also a thermal column of the Kyoto University Research Reactor. All of the radioassays were performed by -ray spectrometry with HPGe-detectors. The present results from the different types of irradiation are compared and discussed in terms of elemental abundances and rock types. 相似文献
997.
Furostifoline, a furo[3,2-a]carbazole alkaloid, was synthesized in 10% overall yield in four steps from 2-acetyl-3-bromofuran. The key step of this synthesis was the 2-substituted indole formation with tetrabutylammonium fluoride (TBAF) from 2-(2-propenyl)-3-((2-ethoxycarbonylamino)phenylethynyl)furan, which was easily prepared from ethyl 2-ethynylphenylcarbamate with 3-bromo-2-(2-propenyl)furan by the Sonogashira reaction. 相似文献
998.
Matsumi N Mori A Sakamoto K Ohno H 《Chemical communications (Cambridge, England)》2005,(36):4557-4559
Physical properties of liquid imidazole-borane complex were investigated to demonstrate their utility as aprotic polar solvents or liquid electrolytes appropriate for selective ion transport. 相似文献
999.
Kohshiroh Mizuno Akihiro Hirata Kunihiko Takeda 《Polymer Degradation and Stability》2007,92(12):2257-2263
The relation between the thermal decomposition and flammability of polynorbornene (PNB) synthesized by addition polymerization was analyzed. In a small-sized vertical combustion test, the PNB did not combust or drip, and the first ignition was extinguished in the combustion test with a cone calorimeter. The decomposition products of PNB were of some low molecular weight compounds with random scissions on the norbornene structure, and alkene (with 12 carbons in the PNB used in this study) was selectively generated by retro-Diels-Alder reaction. When the zeolite was added, the decomposition was accelerated and low molecular weight products increased, especially H2O. These results suggested that the flammability of the thermal decomposition gas was caused by the zeolite, which changed the composition of decomposition products. The lower flammability limits calculated in Le Chatelier's equation were increased from 0.9 to 1.3 by the zeolite. The flame retardancy of PNB was observed because the amount of H2O as an inert gas and the lower flammability limit was increased. 相似文献
1000.
A new glycodendrimer type has been introduced that is designed on the basis of shape-persistent polyphenylene dendrimers. The sugar installation occurs not only on the dendrimer surface but also within the hydrophobic internal scaffold. The synthesis has been accomplished via both convergent and divergent routes by employing the Schmidt glycosylation and the Diels-Alder reaction. This new glycodendrimer has been found to exhibit water-solubility, while conserving hydrophobicity of the interior environment despite the incorporation of sugars. 相似文献