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81.
Several potassium selenocarboxylates were synthesized in moderate to good yields by the direct reaction of acyl chlorides with potassium selenide. The potassium salts were readily oxidized with XeF2 to give diacyl diselenides in quantitative yields. The structure of di(4‐methoxybenzoyl) diselenide was established by X‐ray diffraction analysis. Intramolecular interactions between the carbonyl oxygen and the selenium that is connected to the opposite carbonyl group were observed. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 373–379, 1999 相似文献
82.
Yuichi Shimazaki Hiroshi Yokoyama Osamu Yamauchi 《Angewandte Chemie (International ed. in English)》1999,38(16):2401-2403
A unique bonding of indole to a metal ion has been established. Two new tridentate N ligands with a pendent indole ring gave CuI complexes 1 and 2 , the latter of which exhibits the new form of bonding between the CuI ion in a distorted tetrahedral geometry and the indole C(2)−C(3) moiety. The bond is dependent upon the length of the side chain and therefore the accessibility of the ring to the metal center. 相似文献
83.
Donglin Fu Xuemin Rao Jinyi Xu Genzoh Tanabe Osamu Muraoka Xiaoming Wu Weijia Xie 《Tetrahedron letters》2018,59(30):2876-2879
The first total syntheses of naturally occurring cyclodepsipeptides Hikiamides A–C are described. The key linear pentapeptide precursors, prepared efficiently via Fmoc-solid-phase synthesis, were cyclized in dilute solution to provide the target Hikiamides A–C. The structures of the synthetic Hikiamides A–C were characterized by NMR and HRMS spectroscopy which were in agreement with those of natural products. 相似文献
84.
Shohei Nakamukai Kentaro Takada Kazuo Furihata Yuji Ise Shigeru Okada Yasuhiro Morii Nobuhiro Yamawaki Tomohiro Takatani Osamu Arakawa Kirk R. Gustafson Shigeki Matsunaga 《Tetrahedron letters》2018,59(26):2532-2536
Stellatolide H (1) was isolated from a deep-sea sponge Discodermia sp. as the cytotoxic constituent. The planar structure of 1 was elucidated on the basis of the NMR spectroscopic and mass spectrometric data. The absolute configurations of the constituent amino acid residues were determined by the Marfey’s method. Stellatolide H (1) is a peptide lactone of the callipeltin class with its N-terminus blocked by 3-hydroxy-6,8-dimethyldeca-(4Z,6E)-dienoic acid (Hdda). 相似文献
85.
Mariko Kitajima Tomomi Yanagisawa Mari Tsukahara Yasuka Yamaguchi Noriyuki Kogure Ruri Kikura-Hanajiri Yukihiro Goda Osamu Iida Yasushi Sugimura Nobuo Kawahara Hiromitsu Takayama 《Tetrahedron》2018,74(4):441-452
Three new biphenyl ether quinolizidine lactone alkaloids (1–3) and 13 new biphenyl quinolizidine lactone alkaloids (4–16) were isolated from Heimia salicifolia (Lythraceae) together with seven known alkaloids. Their structures were determined by spectroscopic analyses and chemical conversions. 相似文献
86.
Kazuhiko Matsumoto Rika Hagiwara Yasuhiko Ito Osamu Tamada 《Journal of fluorine chemistry》2001,110(2):117-122
Structures of AgAF6 (A=Sb, Ta) have been determined by X-ray single crystal studies at ambient temperatures. AgSbF6 crystallizes in space group Ia
with a=979.85(4) pm, V=9.4076(12)×108 pm3, z=8, and AgTaF6 crystallizes in space group P42/mcm with a=499.49(4) pm, c=960.51(8) pm, V=2.3964(6)×108 pm3, z=2. Only the crystal system and cell parameters were obtained for the isomorphic AgNbF6; primitive tetragonal, a=497.80(10) pm, b=960.40(10) pm, V=2.3799(12)×108 pm3, z=2. The results of the Raman spectroscopy of AgAF6 support the obtained structures. The structures are discussed by comparing with that of AgPF6 and AgAsF6 which have recently been determined in a series of our study. 相似文献
87.
We have recently published three papers (P. Wagner et al., Phys. Chem. 103 (1999) 8245; S. Inagaki et al., J. Am. Chem. Soc. 121 (1999) 9611; A. Carlsson et al., J. Electron Microscopy 48 (1999) 795) that herald a new approach to structural solutions in micro- and mesoporous solid state materials. Among these materials are the first hybrid inorganic–organic mesoporous materials, synthesized using the organosilane compound 1,2-bis(trimethoxysilyl) ethane (BTME). Both organic and inorganic fragments are distributed completely uniformly at the molecular scale in the mesoporous walls. Two distinct phases with two- and three-dimensional (2d- and 3d-) hexagonal periodic pore-arrangements have been detected. We have also recently reported another new cubic hybrid phase with a decaoctahedral crystal morphology. Two new approaches for solving the structures of porous materials from either electron diffraction (ED) or high-resolution electron microscope (HREM) observations have also been developed. The former was successfully applied by combining direct methods for structural analysis of the new microporous crystal SSZ-48, which crystallizes only in very small crystals. The latter technique was applied to 3d-structural analysis of the mesoporous material MCM-48. The structure solutions, in the latter case, are obtained uniquely without preassumed models or parameterization, unlike previous reports. 相似文献
88.
Ikushima Y Hatakeda K Sato O Yokoyama T Arai M 《Angewandte Chemie (International ed. in English)》2001,40(1):210-213
89.
An analytical method was utilized to detect ppt levels of VOCs in air. The method was based on the US-EPA method TO-14, consisting of canister sampling, three module enrichment and GC/MS analysis. Target compounds included chlorofluorocarbons (four kinds), benzene and its derivatives (14), halogenated hydrocarbons (20), and others (three). The minimum detection limits of the method for the target compounds ranged from 0.016 to 0.040 ppb (0.06–0.23 μg/m3). The recoveries of the target compounds ranged from 77 to 113% and relative coefficients of variation (n=4) were 3.0–9.0%. The sampled air was stable for at least 14 days after pressurizing with humidified nitrogen gas at 200 kPa (absolute pressure). The method was applied to analyze the VOCs in the air of Yakushima, a remote island of south-west Japan where no distinct local pollution source is considered. 相似文献
90.