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1.
《化学学报》2012,70(4)
用DFT-B3LYP方法,在基组6-31G水平,对24种3-取代硫基-5-(2-羟基苯基)-4H-1,2,4-三唑类化合物分子进行几何优化,并计算了EHOMO,ELUMO,ENHOMO,ENLUMO,QC1~QC8,QN1~QN3,QO,QS和ΔE1,ΔE2,ΣQ等量子化学描述符(qc).通过最佳变量子集回归建立13种上述化合物对大肠杆菌、白色念珠菌、金黄色葡萄球菌等抑菌活性(AJ:Ae,Am和As)的QSAR模型.对于大肠杆菌的Ae模型的相关系数(R2)和逐一剔除法交叉验证系数Rcv2依次为0.930和0.871,相应白色念珠菌Am模型为0.926和0.869,As模型为0.781和0.572.通过Radj2,F,Rcv2,VIF,AIC,FIT等检验,上述模型具有令人满意的稳健性和预测能力.结果显示ΔE1和ΣQ直接影响这些化合物的生物活性:ΣQ增大,其抑菌活性增强;ΔE1越高,AJ下降.据此提出三唑类化合物分子可能的抑菌机理.由此发现,在三唑类化合物分子的R中合适部位选用吸电子能力较强的取代基团进行结构修饰,有利于提高被修饰后分子的抑菌活性.根据对R进行结构修饰(共提出11种化合物),得出4种抑菌活性均超出100%的三唑类化合物(质量分数为0.01%),希望将来得到生物实验的证实.  相似文献   

2.
采用密度泛函理论B3LYP方法计算了13个13位取代苦参碱衍生物的电子结构,研究了化合物结构与抑制人肝癌细胞HepG2抗癌活性的定量构效关系(QSAR).结果表明:(1)13位取代的苦参碱类衍生物的最低空轨道能ELUMO越低,最低空轨道与最高占据轨道的能隙ΔE越小,化合物抗癌活性越高;(2)分子的能量Etotal、面积S以及体积V越大,其极化度P越大,活性越大;(3)分子的油水分配系数logP越大,活性越大,即分子的疏水性增大活性增强.综合得到了显著性较好的QSAR方程:-lgIC50=97.008-11.759ΔE+818.602QC2-2.132×10-4Etotal,可用于预测该类衍生物抑制人肝癌细胞HepG2的活性并进行分子设计.  相似文献   

3.
采用活性基团拼接法,以2,3-二氯吡啶和马来酸二乙酯为起始原料,由胺基化合物与中间体6合成了10个新的5-吡唑酰胺类化合物,通过IR,1HNMR,13CNMR和元素分析对其结构进行了表征.初步生物活性测试结果表明,在100μg/mL浓度下,化合物7a~7j具有一定杀虫活性.其中化合物7a和7d对褐飞虱的防治效果分别为57.6%和64.4%,与对照药剂噻嗪酮杀虫活性基本相当.作用机制测试结果表明7d对褐飞虱乙酰胆碱酯酶活性的抑制率为75.21%,高于噻嗪酮对褐飞虱乙酰胆碱酯酶的抑制率(52.17%).  相似文献   

4.
基于分子拓扑邻接矩阵,计算了18种苯甲酰硫脲衍生物的原子类型电性拓扑状态指数(En)。通过多元线性逐步回归方法,建立了令人满意的En与苯甲酰硫脲衍生物对金黄色葡萄球菌的抑制活性(D)的定量结构-活性相关模型(QSAR)。该模型的相关系数(R2)、标准偏差(S)分别为0.861及1.273,该模型的计算值与相应实验值基本吻合。经Rcv2、VIF、FIT、AIC等指标检验,所建模型具有良好的预测能力与稳健性。利用该模型探讨了苯甲酰硫脲衍生物对金黄色葡萄球菌的抑制机理。根据进入模型的2个电性拓扑状态指数E1、E7可知,影响苯甲酰硫脲衍生物对金黄色葡萄球菌的抑制活性的主要因素是分子的二维结构特征-CH3和在芳环中=CH-等结构碎片。由结构修饰提出5种化合物,其中3种的抑菌活性均超出18mm,有待以后生物实验予以证实。  相似文献   

5.
为了从吡唑肟类化合物中寻找新的活性物质,通过活性亚结构拼接方法,设计并合成了一系列未见文献报道的新型含取代嘧啶环结构的吡唑肟类衍生物.采用~1H NMR,~(13)C NMR,MS和元素分析确认了目标化合物的结构.初步的生物活性测试结果表明,部分化合物显示出一定的杀虫活性.在测试浓度为500μg/m L时,化合物6b和6c对蚜虫的杀死率分别为60%和70%,化合物6a,6b,6c和6d对褐飞虱的杀灭效果分别为100%,100%,100%和90%.当测试浓度降至100μg/m L时,化合物6a,6b和6d对褐飞虱仍表现出中等水平的杀虫效果,其杀死率分别为60%,60%和50%.此外,化合物6f,6g和6m在测试浓度为500μg/m L时对粘虫的杀死率分别为80%,70%和90%.  相似文献   

6.
在B3LYP/6-311G基组水平下,运用密度泛函理论(DFT)的量子化学方法,对20种重氮乙烷新烟碱类杀虫剂分子的电子结构特征进行了研究,获得了它们的前线轨道能(EHOMO、ENHOMO、ELUMO、ENLUMO等)、原子电荷(Qi)、摩尔熵(Sm)、偶极矩(μ)等量化参数与物理性质。经最佳变量子集回归研究发现,重氮乙烷新烟碱类杀虫剂分子对果蝇n AChRs、哺乳动物α4β2亚型的亲和力常数(p KD、p KA)分别与ELUMO、QW、QF、QN等参数具有良好的线性关系。逐一或逐四剔除交互验证以及VIF、tα/2检验,所建2个QSAR模型具有良好的稳健性及预测能力。根据2个QSAR模型推断了重氮乙烷新烟碱类分子可能的杀虫机理。进一步研究发现,在重氮乙烷新烟碱类分子的吡啶环上的合适部位,选用不含复键的吸电子能力较强的取代基团对其进行结构修饰,有利于提高修饰后分子的生物活性。基于分子17,设计出4种经结构修饰后对果蝇n AChRs亲和力显著提高的重氮乙烷新烟碱类分子(分别是分子27,28,30和31),希望能得到实验的证实。  相似文献   

7.
苯胺及苯酚类对水生生物毒性的QSAR研究   总被引:1,自引:0,他引:1  
分别测定了取代苯胺和苯酚对鲤鱼 (Cyprinuscarpio)的 96h LC50 ,对发光菌 (Photobacteriumphosphoreum)的1 5min EC50 以及对绿藻 (Scenedesmusobliquus)的 4 8h EC50 。三种水生生物的毒性之间有显著的相关。使用量子化学MOPAC 6 0 AM1法计算了分子最低空轨道能 (ELUMO)。使用ELUMO 和疏水性参数logP对毒性值进行了定量构效关系 (QSARs)研究 ,得到如下方程 :鲤鱼 :log 1 LC50 =3.30 -0 .78ELUMO+ 0 .33logP ,n =1 6 ,R2 =0 .86 9,S .E .=0 .335,F =4 3.2 2 ,P =0 .0 0 0 ;发光菌 :log 1 EC50 =2 .4 6 -0 .51ELUMO+ 0 .4 3logP ,n =1 6 ,R2 =0 .759,S .E .=0 .4 41 ,F =1 8.85,P =0 .0 0 0 ;绿藻 :log 1 EC50 =2 .52 -0 .59ELUMO+ 0 .32logP ,n=1 4 ,R2 =0 .851 ,S .E .=0 .32 6 ,F =2 8.6 0 ,P =0 .0 0 0 .对于含硝基或多个卤原子的化合物 ,其毒性主要与细胞内的反应及疏水性有关 ,而对于苯胺和苯酚 ,其毒性主要与疏水性有关。  相似文献   

8.
用量子化学从头算方法,对亚苄丙二腈衍生物的定量构效关系(QSAR)进行了研究,结果显示:指示变量I,偶极矩Dipole和最低空轨道的能量ELUMO对亚苄丙二腈衍生物的抑制活性有很大影响,回归分析得到了相关性好的相关模型(R=0.95).I=0时,亚苄基丙二腈类衍生物的抑制作用由其化学反应性决定;I=1时其抑制作用由其静电性决定.  相似文献   

9.
应用密度泛函理论方法,在B3LYP/6-311G**水平上对25种取代苯酚进行全优化计算获得优势构象,从获得的分子构象模型中提取了多种量子化学参数,结合文献中取代苯酚诱发浮萍萎黄的活性数据(pC),采用多元线性回归方法成功建立了取代苯酚诱发浮萍萎黄活性的定量预测模型.经逐步回归筛选变量后,所建模型的相关系数R为0.972,去一法交叉验证复相关系数Rcv2为0.932,外部预测集交互检验Qext2为0.931,模型具有较高的拟合精度和较好的预测效果.模型结果表明:最低空轨道能ELUMO及分子体积V对取代苯酚的毒性大小有较大的制约作用;取代苯酚对浮萍所表现出来的毒性随着ELUMO的降低和V的增大而增大;所建两变量模型(1)能较好地预测取代苯酚诱发浮萍萎黄活性.  相似文献   

10.
苦皮素的结构修饰研究   总被引:5,自引:0,他引:5  
尚玉俊  赵天增  傅经国 《化学研究》2002,13(2):35-38,48
以苦皮藤中的有效杀虫成份苦皮素为原料合成了 8种衍生物 ,用元素分析、核磁共振波谱等数据对其进行了结构确证 .以 3龄虫 (mythimnaseparatawalker)为试虫 ,测定了它们的杀虫活性 .结果表明 ,苦皮素衍生物对粘虫表现程度不等的杀虫效果  相似文献   

11.
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   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

15.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

16.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

17.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

18.
The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.  相似文献   

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20.
设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。  相似文献   

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