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1.
Minoru Koyama Dr. Takafumi Kawakami Dr. Takashi Okazoe Prof. Dr. Kyoko Nozaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(46):10913-10917
Methacrylic esters, represented by methyl methacrylate (MMA), are widely used as commodity chemicals. Here, the one-pot synthesis of methacrylic esters from acetone, a haloform and alcohols in the presence of an organic base is described. Using DBU as the organic base for the reaction of acetone, chloroform and methanol in acetonitrile afforded MMA in 66 % yield. When the solvent was replaced by benzonitrile, the product MMA was successfully purified by distillation. Applicability of this process to various alcohols was also investigated to show ethyl, phenyl, CF3CH2, and n-C6F13CH2CH2 esters were obtained in moderate yields. The use of bromoform instead of chloroform resulted in the improvement of the yield, for example, methyl and n-C6F13CH2CH2 esters up to 81 and 70 %, respectively. The reaction with deuterated starting materials acetone-d6 and MeOH-d4, with DBU in acetonitrile afforded deuterated MMA (MMA-d8) in 70 % yield. 相似文献
2.
Yasushi Seike Ryoko Fukumori Yukiko Senga Hiroki Oka Kaoru Fujinaga Minoru Okumura 《Analytical sciences》2004,20(1):139-142
A new and simple method for the determination of hydroxylamine in environmental water, such as fresh rivers and lakes using hypochlorite, followed by its gas choromatographic detection, has been developed. A glass vial filled with sample water was sealed by a butyl-rubber stopper and aluminum cap without head-space, and then sodium hypochlorite solution was injected into the vial through a syringe to convert hydroxylamine to nitrous oxide. The head-space in the glass vial was prepared with 99.9% grade N2 using a gas-tight syringe. After the glass vial was shaken for a few minutes, nitrous oxide in the gas-phase was measured by a gas chromatograph with an electron-capture detector. The dissolved nitrous oxide in the liquid-phase was calculated according to the solubility formula. The proposed method was applied to the analysis of fresh-water samples taken from Iu river and Hii river, flowing into brackish Lakes Nakaumi and Shinji, respectively. 相似文献
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Suchada Suntornchashwej Dr. Khanit Suwanborirux Dr. Kazushi Koga Minoru Isobe Prof. Dr. 《化学:亚洲杂志》2007,2(1):114-122
Malyngamide X ( 1 ), the first (7R)‐lyngbic acid connected to a new tripeptide backbone, was isolated from the Thai sea hare Bursatella leachii. The gross structure of 1 was established on the basis of 1D and 2D NMR and mass spectroscopic data. Combination of the NMR spectroscopic experiments with α‐methoxy‐α‐(trifluoromethyl)phenylacetic acid esters, 2,2,2‐trifluoro‐1‐(9‐anthryl)ethanol chiral solvating agent, and molecular mechanics of 1 and the synthetic molecular fragments allowed us to determine the absolute stereochemistry of all six stereogenic centers without hydrolytic degradation of the compound. Compound 1 displayed moderate cytotoxic, antitubercular, and antimalarial properties. 相似文献
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Minoru Murata 《Journal of Functional Analysis》2002,194(1):53-141
We consider positive solutions of elliptic partial differential equations on non-compact domains of Riemannian manifolds. We explicitly determine Martin boundaries and Martin kernels for a class of elliptic equations in skew product form by exploiting and developing perturbation theory for elliptic equations and short/long-time estimates for fundamental solutions of parabolic equations. 相似文献
7.
Rungnapha Saeeng Uthaiwan SirionPoolsak Sahakitpichan Minoru Isobe 《Tetrahedron letters》2003,44(33):6211-6215
A convenient method for C-glycosidation (alkynylation) with various silylacetylenes to d-glucal by iodine molecule via iodo-oxonium intermediates provided exclusively the α-acetylene glycoside products. Eleven successful examples are shown under this condition. 相似文献
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Various N-sulfenyl heterocycles were synthesized by transamination of sulfenamides using a chlorine gas-free method. The N-sulfenyl heterocycles behaved as sulfenylating reagents of anilines; N-sulfenylbenzimidazoles were the most effective. 相似文献
10.
Takahiro Gunji Ryosuke Shimano Koji Arimitsu Yoshimoto Abe 《Journal of polymer science. Part A, Polymer chemistry》2006,44(8):2542-2550
Tetraethoxysilane (TEOS) and polyethoxysiloxanes (PEOSs; prepared by the acid‐catalyzed hydrolytic polycondensation of TEOS) were subjected to the sol–gel process in the presence of cetyltrimethylammonium bromide (CTAB), respectively. The PEOSs with Mw 700–26,000, as prepared by sol–gel coating of TEOS and PEOS under various conditions, were used. Uniform and crack‐free thin films of thickness 276–613 nm were prepared by spin‐coating of a PEOS solution containing CTAB. When the coating films were sintered at 400 °C, the combustion of ethoxy groups and CTAB took place to provide porous silica thin films. The structure of the thin films was found to be dependent on the molecular weight of PEOS and the molar ratio of CTAB/Si: lamellar or hexagonal phase was observed for Mw less than 15,000 and for CTAB/Si molar ratios greater than 0.10. Honeycomb structures were observed for Mw less than 5000 and for CTAB/Si molar ratios of 0.15. The honeycomb structure was also observed by atomic force microscopy and transmission electron microscope. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2542–2550, 2006 相似文献