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The first total enantioselective synthesis of (+)-(4S, 8R)-8-epi-β-bisabolol(+)- 1 and of (?)-(4R, 8 S )-4-epi-β-bisabolol ((?))? 1 ) is reported. The key step in the synthesis is the kinetic resolution of (±)? 5 by means of the Sharpless epoxidation yielding (?)- and (+}? 6 , respectively. Reduction of the epoxides with LiAlH4 gave the diols (+)-and(?)? 7 which were transformed into (+)- and (?)? 8 , respectively, via the corresponding mesylate. Reaction of these epoxides with the Grignard reagent derived from homoprenylbromide, assisted by Li2CuCl4, finished the synthesis of the target compounds 1 with high diastereo- and enantioselectivity. 相似文献
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《Analytical letters》2012,45(6):455-464
Abstract 4-(p-Sulfophenylazo)-l, 8-dihydroxynaphthalene (SPADN) was synthesized to study as a new reagent for the spectro-photometric determination of boron, measuring its absorbance on addition of boron present as boric acid at pH 8.6. The procedure involved mixing aliquots of the sample, ammonium buffer, EDTA and SPADN solutions. Various exchange equilibrium constants in the ion-association extraction systems of SPADN with zephiramine were also determined. 相似文献
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DING Ming-wu ** SHU Ya-li LIU Zhao-jie Institute of Organic Synthesis Central China Normal University Wuhan P. R. China 《高等学校化学研究》2003,19(3):302-305
IntroductionMany N- heterocycles including 4H - imidazolin-4- ones show bactericidal and fungicidal activities,especially those with a 2 - alkoxyl substituent[1— 5] .The efforts to discover the new biologically activederivatives reflected by the still important numberof publications and patents have been devoted tothe subject[6— 11] .For example,some 2 - amino or 2 -alkylthio substituted 4H- imidazolin- 4- ones showsignificant antifungal and antibacterial activi-ties[7— 9] ,whereas others … 相似文献
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《Tetrahedron: Asymmetry》2007,18(17):2091-2098
The synthesis of new (4S,8aS)- and (4R,8aS)-4-phenyl-perhydropyrrole[1,2-a]pyrazine-1,3-diones in the cyclocondensation reaction of the respective derivatives of l-prolineamide is described. The effect of the amount of NaOEt, temperature, and reaction time on the proportions of diastereomers formed in the cyclocondensation reaction was examined. The structures of the diastereomers were confirmed by GC/MS, HRMS, HPLC, XRD, and 1H and 13C NMR investigations. 相似文献
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Münzel M Szeibert C Glas AF Globisch D Carell T 《Journal of the American Chemical Society》2011,133(14):5186-5189
UV irradiation of cellular DNA leads to the formation of a number of defined mutagenic DNA lesions. Here we report the discovery of new intrastrand C(4-8)G and G(8-4)C cross-link lesions in which the C(4) amino group of the cytosine base is covalently linked to the C(8) position of an adjacent dG base. The structure of the novel lesions was clarified by HPLC-MS/MS data for UV-irradiated DNA in combination with chemical synthesis and direct comparison of the synthetic material with irradiated DNA. We also report the ability to generate the lesions directly in DNA with the help of a photoactive precursor that was site-specifically incorporated into DNA. This should enable detailed chemical and biochemical investigations of these lesions. 相似文献
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M. Madesclaire P. Coudert V. Goumet V. P. Zaitsev J. V. Zaitseva 《Chemistry of Heterocyclic Compounds》2006,42(6):813-817
The configuration of the asymmetric atoms in the molecule of (1R,2R,4S,5S,8S)-2,8-bis(4-chlorophenyl)-4-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3,3,0]octane
has been determined using X-ray analysis.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 930-934, June, 2006. 相似文献
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I. A. Vershinina O. V. Gornukhina T. V. Lubimova O. A. Golubchikov A. S. Semeikin 《Russian Journal of General Chemistry》2016,86(9):2232-2235
A methodology of the synthesis of 4-(8-quinolylazo)resorcinol (QAR) and 1-(8-quinolylazo)-2-naphthol (QAN) was developed. The synthesized compounds were used to modify an oxidized charcoal sorbent. The sorbent efficiently adsorbs copper(II) and zinc(II) cations to form surface electroneutral chelate complexes. The conditions of sorption and desorption of zinc(II) and copper(II) were studied. 相似文献
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新试剂5-(4-氯苯基偶氮)-8-苯磺酰氨基喹啉光度法测定微量铜 总被引:5,自引:0,他引:5
在 p H 8.5的 Na2 B4 O7- HCl介质及有氯化十六烷基吡啶 ( CPC)存在时 ,室温下铜 ( )与 5 - ( 4 -氯苯基偶氮 ) - 8-苯基磺酰氨基喹啉 ( CPBSQ)迅速反应 ,生成络合比为 1∶ 3的有色络合物。研究了反应的最佳条件 ,建立了一个测定 Cu( )的光度分析新方法。Cu( )的浓度在 0~ 1 4.0 μg/2 5 m L 范围内符合比耳定律 ,其摩尔吸光系数为 8.1 2× 1 0 4 L· mol- 1· cm- 1。方法用于面粉、茶叶及奶粉中铜的测定 ,其相对标准偏差为 0 .5 8%~ 1 .2 % ,标准加入回收率为 95 .5 %~ 1 0 4 .5 %。 相似文献