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排序方式: 共有216条查询结果,搜索用时 31 毫秒
1.
Hiroyuki Nakazumi Takashi Endo Hikaru Sonoda Teijiro Kitao 《Journal of heterocyclic chemistry》1985,22(3):821-824
3-Substituted 2-phenyl-4H-1-benzothiopyran-4-ones (thioflavones) were prepared to test antimicrobial activity. It was found that 3-(phenyl)thiochromone derivatives (isothioflavones) were prepared by the Meerwein reaction of thiochromone with p-nitrobenzenediazonium ion. 3-(Formyl)thioflavone exhibits weak antimicrobial activity against Trichophytons and Candida. 相似文献
2.
Makoto Yuasa Aritomo Yamaguchi Kenichi Oyaizu Yosuke Fujito Mizuki Kitao Tsuyoshi Sato 《先进技术聚合物》2005,16(9):702-705
meso‐Substituted cobalt porphyrins adsorbed on carbon black were prepared as catalysts for the electroreduction of O2. The catalyst, which was prepared by using a homogenizer in mixing cobalt tetraethylporphyrin and carbon black, gave rise to electroreduction of O2 at a remarkably positive potential (Ep = 0.45 V versus saturated calomel electrode (SCE)) and showed a high selectively for the four‐electron reduction (n = 3.8). Electrochemical study and extended X‐ray absorption fine structure (EXAFS) analysis revealed that the adsorbed face‐to‐face dimeric aggregates of cobalt porphyrin molecules were highly efficient catalysts for electroreduction of O2. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
3.
Ichikawa S Tada M Iwasawa Y Ikariya T 《Chemical communications (Cambridge, England)》2005,(7):924-926
Chemoselective hydrogenation of halogenated nitrobenzenes over Pt/C catalysts proceeds effectively in supercritical carbon dioxide (scCO2) to produce halogenated anilines with excellent selectivity; the rate of the hydrogenation of nitro groups is markedly enhanced in scCO2 compared to the neat reaction, and the dehalogenation reaction is significantly suppressed. 相似文献
4.
Tada M Taniike T Kantam LM Iwasawa Y 《Chemical communications (Cambridge, England)》2004,(22):2542-2543
The self-dimerized chiral assembly of vanadium-Schiff-base complexes was found to occur on a SiO2 surface and to be the first heterogeneous catalyst for the asymmetric oxidative coupling of 2-naphthol with 100% selectivity and 90% enantioselectivity. 相似文献
5.
Kunishima M Kitao A Kawachi C Watanabe Y Iguchi S Hioki K Tani S 《Chemical & pharmaceutical bulletin》2002,50(4):549-550
Racemization of the C-terminal amino acid (Ala) has been studied in various solvents during coupling between 4-methoxybenzyloxycarbonyl (Z(OMe))-Gly-L-Ala-OH and phenylalanine benzyl ester (H-Phe-OBzl) with 4-(4,6-dimethoxy-1,3,5-thiazin-2-yl)-4-methylmorpholinium chloride (DMT-MM). The reaction occurred without substantial racemization in AcOEt, tetrahydrofuran (THF), N,N-dimethylformamide (DMF), CH3CN, and 2-PrOH, while a slight racemization was observed in dimethyl sulfoxide (DMSO), EtOH, and MeOH. The extent of racemization may correlate with the polarity of the solvents. 相似文献
6.
-Alumina was synthesized by thermal decomposition of aluminium(III) isopropoxide, and its properties were investigated. The change in its surface area with increasing calcination temperature resembled that of -alumina. Both aluminas had the same acid strength, and their activities in isomerization of 1-butene were the same. -Alumina as a support for molybdenum catalyst in the epoxidation of allyl alcohol also behavedin the same manner as -alumina. Thus -alumina has almost the same catalytic properties as -alumina. 相似文献
7.
8.
Hiroyuki Nakazumi Takashi Endo Toshiyuki Nakaue Teijiro Kitao 《Journal of heterocyclic chemistry》1985,22(1):89-92
3-Amino-4H-1-benzothiopyran-4-one (3-aminothiochromone) was easily prepared by reaction of 3-bromo-thiochromen-4-one with sodium azide in methanol-water. Condensation of 3-aminothiochromone with diethyl ethoxymethylenemalonate and with dimethyl acetylenedicarboxylate gave intermediates, which were thermally cyclized to give 4,10-dihydro-4,10-dioxo-1H[1]benzothiopyrano[3,2-b]pyridinecarboxylates. 3-Formyl-thiochromone was condensed with o-phenylenediamine to give 7-oxo-7,13-dihydro[1]benzothiopyrano[2,3-b]-1,5-benzodiazepine. 相似文献
9.
Optical Review - A graded-index type photonic crystal fiber (GI-PCF) has a graded effective index distribution that can be realized by an α-power air hole diameter distribution in radial... 相似文献
10.
Simultaneous determination of silicate and phosphate in environmental waters using pre-column derivatization ion-pair liquid chromatography 总被引:1,自引:0,他引:1
A highly sensitive HPLC method for the simultaneous determination of soluble silicate and phosphate in environmental waters was developed, using ion-pair liquid chromatography preceded by the formation of their yellow α-heteropolymolybdates. The moderate-pH mobile phase enabled to use a highly efficient reversed-phase silica column. The pre-column coloring reactions at moderate-pH were reproducible for both silicate and phosphate in all quantification ranges with R.S.D.s less than 2% and 5%, respectively. The linear calibration lines between concentrations (mg-SiO2/L and mg-PO4/L) and peak area intensities were obtained for silicate and phosphate both with acceptable determination coefficients (r2) of 0.9999. The limits of determination for both analytes were 0.007 mg-SiO2/L and 0.003 mg-PO4/L, which were calculated theoretically using 10σ/slope. The four-digit dynamic ranges were obtained for 0.007-10 mg-SiO2/L and 0.003-20 mg-PO4/L. The developed method was applied for the analysis of tap water, river water, coastal seawater, well water, hot-spring water, commercial mineral water, and laboratory water. The results were very reasonable and acceptable from the environmental viewpoints, which were well correlated with those confirmed by the molybdenum-blue spectrophotometry. 相似文献