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991.
The isolation and structure elucidation of xyloccensin L from the stem bark of Xylocarpus granatum is described. Xyloccensin L is a highly oxidized heptacyclic A, B, D-seco limonoid with an α-8, 30-epoxy ring and a rare 1, 29 oxygen bridge. 相似文献
992.
化学衍生-高效液相色谱法测定硫氰酸根阴离子 总被引:4,自引:0,他引:4
以α-溴-2,3,4,5,6-五氟甲苯作柱前衍生试剂,经优化衍生和色谱条件,实现了用高效液相色谱法测定硫氰酸根离子。在ODS柱上,用甲醇-水(80:20)作流动相,于254nm检测,得到线性关系良好的工作曲线,最小检测限为4.7ng。分析了吸烟者唾液样品,回收率为93.7%~101.4%。 相似文献
993.
M. Z. Krimer F. Z. Makaev Yu. B. Kal'yan V. P. Tashchi Yu. G. Putsykin 《Russian Chemical Bulletin》1993,42(12):1995-2000
O-Methyloximes and nitrones of a series of substituted 4-[2-hydroxy-2-(1H-1,2,4-triazol-1-ylmethyl)cyclohexylidenemethyl]benzaldehydes have been synthesized, and their fungicidal activity has been assayed. All of them exhibit low fungicidal activity in thein vitro assays and high activity in thein vivo assays; theO-methyl oximes are more active than the corresponding nitrones.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2082–2087, December, 1993. 相似文献
994.
Miyuki Narita Junya Itoh Tohru Kikuchi Fumio Hamada 《Journal of inclusion phenomena and macrocyclic chemistry》2002,42(1-2):107-114
-Cyclodextrin dimer linked with ethylenediamine at the upper rim of the cyclodextrin has been synthesized and then modified with two dansyl moieties inthe presence of N,N'-dicyclohexylcarbodiimide. The sensing ability and bindingproperty of the title compound were investigated for steroids and terpenoids. Thefluorescence intensity of this dimer was decreased when a host–guest complex was formed. The value I/I0, where I0 and I are fluorescence intensitiesin the absence and presence of a guest and I is I0- I, was used as a parameter of sensitivity. This host exhibited a much higher sensitivity and selective molecular recognition ability for bile acids such as ursodeoxycholic acid andchenodeoxycholic acid and terpenoids such as (-)-borneol than the dansyl-modifiedcyclodextrins reported previously including -cyclodextrin dimer. The behaviors of the appended moieties of the host during the formation of host–guest complexes were studied using induced circular dichroism (ICD) and fluorescence spectra. The ICD intensityof this dimer was decreased on accommodation of a guest and this spectral pattern of the title dimer was opposite to that of bis dansyl-modified -cyclodextrin monomer. Theguest-induced variations in the fluorescence and ICD intensities suggest that this dimer formed a 1 : 1 host–guest complex and the appended moieties act as a hydrophobic cap. 相似文献
995.
1 INTRODUCTION Benzimidazole is an interesting heterocyclic ring because it is present in various naturally occurring drugs, such as omeprazole, astemizole and emedastine difumarate[1]. The efficacy of substituted benzimidazoles in the treatment of parasitic infections is well known[2~4], and the pharmacophores in parasitic chemotherapy are established by benzimidazole-substituted moieties. Bis(2-benzimidazoles) and some substituted bis- (benzimi-dazol-2-yl) alkanes have attracted much… 相似文献
996.
The reactions of aliphatic β-amino-β-trifluoromethylvinyl ketones with an excess of ethylenediamine at room temperature afforded
the corresponding 2,3-dihydro-1H-1,4-diazepines or substituted 2-acetonyl-2-trifluoromethylimidazolidines (the latter were obtained when the approach to the
carbonyl group was sterically hindered).
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2305–2308, November, 1998. 相似文献
997.
N. E. Golantsov A. V. Karchava M. A. Yurovskaya 《Chemistry of Heterocyclic Compounds》2006,42(8):1021-1024
Methods of obtaining ketones and enamino esters have been developed on the basis of reactions of 1-(1-phenylethyl)indole-2-carbonitrile
with organomagnesium and organozinc compounds. Removal of a benzyl group from the indole nitrogen atom by the Grignard reagent
has been discovered.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1179–1183, August, 2006. 相似文献
998.
Summary Rare earth elements 1,3,5-benzenetricarboxylates were prepared as solids of the general formula Ln(C9H3O6)·nH2O, where n=6 for La-Dy and n=4 for Ho-Lu,Y. Their solubilities in water at 293 K are of the order 10-4-10-6 mol dm-3. The IR spectra of the complexes indicate that the carboxylate groups are bridging and bidentate chelates. Hydrated 1,3,5-benzenetricarboxylates
lose water molecules during heating in one step (La-Tb), two steps (Y, Ho-Tm) or three steps (Dy, Yb, Lu). The anhydrous complexes
are stable up to 573-742 K and decompose to oxides (Ce-Lu) at higher temperatures. 相似文献
999.
A. V. Vasilyev N. P. Solov'eva N. Ya. Podhaluzina A. Yu. Tolmachev V. F. Traven 《Chemistry of Heterocyclic Compounds》2003,39(4):534-538
Fries rearrangement of 7-acetoxy-4-methylquinolin-2-one and subsequent condensation of the 6-acetyl-7-hydroxy-4-methylquinolin-2-one obtained with -chloro ketones gives a series of furo[3,2-g]quinolin-7-ones. 相似文献
1000.
反相高效液相色谱法测定杀虫剂中吡虫啉的含量 总被引:5,自引:0,他引:5
报道了反相色谱法测定杀虫剂中吡虫啉的含量,该法采用YWG-C18(250mm×4.0mm,10μm),柱,以甲醇-水(含0.1%二乙胺,pH5.0),(35:65,V/V,1.0mL/min)为流动相,紫外检测波长为270nm,0.16AUFS,样品可直接用甲醇超声提取。样品中吡虫啉平均回收率≥97.43%,相对标准偏差≤2.1%。 相似文献