共查询到20条相似文献,搜索用时 46 毫秒
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为了寻求新颖的抗糖尿病药物, 我们将芳香醛、对溴苯乙酮和磺胺嘧啶通过一步反应直接合成了16个未见报道的含有磺胺嘧啶结构的β-氨基酮化合物, 制备方法简便、反应条件温和, 收率为10.0%~80.1%. 所制备的化合物通过1H NMR, 13C NMR, MS和HRMS进行结构表征与确证. 对这些化合物进行α-葡萄糖苷酶抑制活性初步检测, 结果表明部分化合物在低浓度范围(8.1~9.3 nmol•mL-1)具有一定的α-葡萄糖苷酶抑制活性. 相似文献
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从链霉菌S001的重组菌株S001-cbm-OX4-ikaD中分离获得1个新多环特特拉姆酸大环内酰胺(Po TeMs)类化合物3-hydroxycombamide Ⅰ (2),通过一维、二维核磁共振波谱(NMR)和高分辨质谱(HRMS)数据分析确定其化学结构.化合物2的C-3位羟基推测为宿主链霉菌S001所含羟基化酶催化形成.分别采用滤纸片法和噻唑蓝(MTT)比色法测定了化合物2的抗菌和细胞毒活性,结果显示化合物2无明显活性.此外,化合物2在100μmol/L时对鼠伤寒沙门菌Ⅲ型分泌系统(T3SS)无抑制活性.结果显示Po TeMs的C-3位羟基化修饰可能发生在多环体系氧化修饰之后. 相似文献
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利用不饱和度计算桥环化合物的环数 总被引:2,自引:0,他引:2
正确算出桥环化合物的环数是正确命名桥环化合物的基础。目前确定环数的方法主要有五种,即规则多面体面数法、断键法、块数法、P.A.Reddy计算法、桥头碳原子数法。笔者受不饱和度概念的启发,建立了一种桥环化合物环数的计算方法。所谓不饱和度(又称氢不足指数、双键等价数)指的是在某一化合物结构中环与双键的总数目(叁键当作两个双键)。若知道有机物的分子式,便可由下式求算其不饱和度(Ω)。 相似文献
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丙交酯合成过程的理论及实验研究 总被引:7,自引:0,他引:7
采用密度泛函方法研究了丙交酯的合成过程, 优化了合成过程中可能出现的化合物的几何构型, 分析了各化合物的振动频率和偶极矩. 在B3LYP/6-31G*和B3LYP/6-311+G*水平上进行了各化合物的能量计算, 得到了所设计的各模型反应的焓变和吉布斯自由能变. 结果表明, 所选择的各模型反应为吸热反应且近似可逆, 水的控制对丙交酯的形成很重要. 根据量化计算结果与丙交酯合成实验中不同阶段反应体系红外谱图的变化, 提出了丙交酯合成的可能机理. 相似文献
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利用手持技术改进测定乙醇分子结构实验 总被引:1,自引:0,他引:1
利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1989,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988. 相似文献
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由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。 相似文献
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Mustafa R. Ibrahim Zacharia A. Fataftah Paul von Ragu Schleyer Peter D. Stout 《Journal of computational chemistry》1987,8(8):1131-1138
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases. 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1988,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae. 相似文献
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Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin
E. I. Kapinus V. A. Ganzha B. M. Dzhagarov E. I. Sagun V. B. Pavlenko 《Theoretical and Experimental Chemistry》1989,25(2):146-151
The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989. 相似文献
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The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted
indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator
model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was
established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing
analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997. 相似文献