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1.
以取代苯甲醛为原料,采用醇醛缩合反应和珀金反应完成了反,反-2,4-二甲基-5(对硝基苯基)戊-2,4-二烯酸和反,反-2,4-二甲基-5-(间硝基苯基)戊-2,4-二烯酸的有效全合成,并确定了最佳反应条件,化合物3b为尚未见文献报道的新化合物,其结构经红外光谱,核磁共振证实。  相似文献   

2.
Protein modification by active aldehydes is associated with ageing and some chronic diseases, and it is closely related to food quality and safety. In this study, the modification of bovine serum albumin (BSA) using trans,trans-2,4-decadienal at various concentrations (0–10 mm ) is investigated. The results show that the changes in the number of free amino groups and arginine residues, carbonyl formation, aggregation characteristics, and fluorescent lipofuscin-like pigments (LFLP) fluorescence are more severe at (E,E)-2,4-decadienal concentrations of 4–10 mm , whereas the conformational changes are more significant at low concentrations (0.1–2 mm ). In the BSA modified by 1–10 mm (E,E)-2,4-decadienal, the microenvironment of tryptophan residues to become more hydrophobic, the structure became compact, hydrophobic binding sites decreases, molecular weight and particle size increases, and covalently cross-linked heterogeneous aggregates increases. At the same time, the relationship between the oxidation parameters and samples is explained using principal component analysis and hierarchical cluster analysis. Practical Applications: (E,E)-2,4-decadienal is highly electrophilically active with biomacromolecules. However, compared to the widely studied malonaldehyde (MDA), acrolein (ACR), 4-hydroxynonenal (HNE), and 4-oxo-trans-2-nonenal (ONE)-protein adducts, research on the modification of a protein by (E,E)-2,4-decadienal is insufficient, and the chemical nature of (E,E)-2,4-decadienal-protein adducts is not clear. This study may be useful for extending our understanding of the specific role of (E,E)-2,4-decadienal in the formation of modified proteins during the occurrence of chronic diseases and provides a theoretical reference for food quality and safety problems caused by protein carbonylation during processing and storage.  相似文献   

3.
研究新型制冷剂的热物理性质是制冷剂替代工作的基础。在新型环保HFO类制冷剂中,R1336mzz(E)因其与R245fa相似的热力学性质,在高温热泵和有机朗肯循环中有希望成为R245fa的替代制冷剂。采用旋转式毛细管黏度计,测量了278 ~ 333 K温度范围内R1336mzz(E)的液相黏度,并根据四种形式的液体黏度方程对实验数据进行拟合,得到R1336mzz(E)黏度与温度的关联式。结果表明,采用修正后的非线性Andrade关联式所关联的精度最高,其关联结果与实验结果之间平均绝对偏差(AAD)和最大绝对偏差(MAD)分别为0.170 %和0.311 %。基于R1336mzz(E)于高温热泵的应用前景,通过拟合所得的四种黏度关联式对实验数据进行至临界温度(403.37 K)的外推,根据误差分析,采用修正后的非线性Andrade关联式外推得到的数据最可靠,可作为R1336mzz(E)临界温度附近的黏度数据。研究工作可以为R1336mzz(E)的替代应用研究提供基础数据。  相似文献   

4.
The antennae of male spotted tentiform leafminers, Phyllonorycter blancardella, from Ontario, Canada, exhibited similar electroantennogram responses when stimulated with E10-12:Ac or E4,E10-12:Ac. In field trapping experiments, E10-12:Ac was two-fold or more attractive than E4,E10-12:Ac, and E4,E10-12:Ac did not enhance the attractiveness of E10-12:Ac. E4,E10-12:Ac has not been identified in the pheromone of P. blancardella and it is hypothesized that the structural similarity of this compound and E10-12:Ac, the major pheromone compound of this species, may be responsible for the electrophysiological and behavioral responses to E4,E10-12:Ac. The possible reasons for the disparity between the results of our field trapping experiments and those carried out in Nova Scotia, Canada, and Massachusetts, USA., where E4,E10-12:Ac was found to be two to four times more attractive to P. blancardella than E10-12:Ac, are discussed.  相似文献   

5.
研制GBW(E)130573门尼粘度标准物质,该标准物质的不确定度按照JJF 1059.1-2012规定分析不确定度各分量并进行评定。不确定度的来源主要为各定值实验室检测的分散性、样品的均匀性与稳定性、试验温度、试验时间、设备转速。经评定GBW(E)130573门尼粘度标准物质的不确定度为0.9。  相似文献   

6.
Two sex pheromone components of the gum leaf skeletonizer, Uraba lugens (Lepidoptera: Nolidae), recently established in New Zealand, were identified. Gas chromatography (GC) electroantennographic detection analyses of female pheromone gland extracts gave three compounds that consistently elicited antennal responses. Chemical analyses, using GC and GC-mass spectrometry, in conjunction with 4-methyl-1,2,4-triazoline-3,5-dione and dimethyldisulfide derivatizations, identified these compounds as (10E,12Z)-hexadecadien-1-yl acetate (E10,Z12-16:Ac), (10E,12Z)-hexadecadien-1-ol (E10,Z12-16:OH), and (Z)-11-hexadecen-1-yl acetate (Z11-16:Ac). A trapping trial in Queensland, Australia, in 2002, indicated that a blend of the two major components E10,Z12-16:Ac and E10,Z12-16:OH could attract gum leaf skeletonizer males. In the same trial, E10,Z12-16:Ac alone trapped large numbers of an unidentified nolid, Nola spp. Further trials in Auckland, New Zealand established that these two components were sufficient and necessary for trap catch of males; adding minor gland components, (10E,12E)-hexadecadien-1-yl acetate (E10,E12-16:Ac), Z11-16:Ac, or octadecan-1-ol (18:OH), to the two-component lure did not result in increased trap catches. Behavioral observations and gland analyses of the Auckland population revealed that female moths begin calling soon after emergence, with peak calling and pheromone production occurring 7 hr into the scotophase. Analysis of gland extract at two-hourly intervals during the first activity period showed that the ratio of E10,Z12-16:Ac to E10,Z12-16:OH (mean of 86: 14, respectively) and pheromone titer were fairly constant. No qualitative or quantitative differences in pheromone components were detected between gland extracts from Tasmanian univoltine and Auckland bivoltine populations of U. lugens.  相似文献   

7.
(E)-3-(3,4-二羟基苯基)丙烯酸的合成   总被引:1,自引:0,他引:1  
方方  吉爱国 《化学试剂》2006,28(12):749-750
以3,4-二甲氧基苯甲醛为原料,微波辐射下与丙二酸发生Knoevenagel反应后,在TMSCl/NaI/CH3CN体系中脱甲基合成了标题化合物。探讨了影响产率的因素并对终产物进行了结构表征,总收率为90%。  相似文献   

8.
A methanol extract ofAchillea millefolium L. showed activity against 24-hr-old larvae ofAedes triseriatus. Bioassay- and TLC-monitored fractionation yielded a neutral fraction which was refined further by column chromatography to afford the antilarvalN-(2-methlpropyl)-(E,E)-2,4-decadienamide which was identified by spectral methods and through comparisons with a synthesized sample. Isolated and synthesized amides at 5 ppm resulted in 98 and 100% mortality of 24-hr-oldA. triseriatus larvae. TheN-(2-methylpropyl)-amides of decanoic and (E)-2-decenoic acids showed the same order of antilarval activity asN-(2-methylpropyl)-(E,E)-2,4-decadienamide, butN-(2-methylpropyl)sorbamide was inactive.  相似文献   

9.
采用一种含有强极性官能团的新型增韧剂马来酸酐接枝(乙烯/甲基丙烯酸酯)共聚物[(E/MAK)-g-MAH]对聚碳酸酯(PC)进行增韧研究。实验结果表明,随着(E/MAK)-g-MAH含量的增加,PC/(E/MAK)-g-MAH共混体系的冲击强度显著提高。当(E/MAK)-g-MAH质量分数为20%时,冲击强度达59.6kJ/m^2,是纯PC冲击强度的近6倍。另外(E/MAK)-g-MAH还使共混体系的断裂伸长率提高,流动性得到明显改善。  相似文献   

10.
Electrosynthesis of (E)-Ethenyl-O-ethyl-thiocarbonates Electrochemical reductions of 4-aryl- and 4,5-diaryl-1,2,3-thiadiazols ( 1 – 5 ) in acetonitrile/0,1 M tetraalkylammonium-supporting-electrolyte at Hg-cathodes in the presence of ethylchloroformiate (CAE) yield (E)-S-(2-aryl) ethenyl- and S-(1,2-diaryl)ethenyl-O-ethyl-thiocarbonates ( 1a – 5a ). The S-carboxylation proceeds via preformation of cyclic-voltammetric- and 1H-nmr-provable CAE-complexes, ring-opening and N2-elimination in a two-electron reduction. The synthesis including a rearrangement of a N-tos-S-CAE-complex is discussed in context with CNDO/2 quantum chemical calculation. Thermochemical synthesis of this new class of thiocarbonates proved unsuccessful.  相似文献   

11.
Field attraction ofCydia nigricana males to synthetic female sex pheromone (E,E)-8,10-dodecadien-1-yl acetate, formulated on red rubber septa, declined continuously during two weeks. This was due to isomerization of (E,E)-8,10-dodecadien-1-yl acetate: eight days after application of purifiedE,E isomer, the proportion ofE,Z;Z,E; andZ,Z isomers in rubber septa aged in the laboratory was 4%; a 5% addition of any one of these isomers to fresh lures of (E,E)-8,10-dodecadien-1-yl acetate significantly reduced male attraction. Stereospecific syntheses of (E,Z)-, (Z,E)-, and (Z,Z)-8,10-dodecadien-1-yl acetate are described. The pheromone gland ofCydia nigricana contains 0.8 ng/female of (E,E)-8,10-dodecadien-1-yl acetate, accompanied by three monounsaturated acetates, (E)-9-dodecen-1-yl acetate, (Z)-5-tetradecen-1-yl acetate, and (Z)-7-tetradecen-1-yl acetate (0.1 ng/female each). These compounds did not augment male trap catch when added to (E,E)-8,10-dodecadien-1-yl acetate.  相似文献   

12.
Abstract

A kinetic model for the interfacial reaction of copper extraction with Individual 1-(2'-hydroxy-5'-nonylphenyl)-1-ethanone (E)-oxime and 1-(2'-hydroxy-5'-methylphenyl)-1-decanone (E)-oxime having the same hydrophobicity was used to interpret the effect of hydroxyoxime partition and interfacial activity upon the rate of copper extraction from acidic sulfate solutions. Due to similar hydrophobicity of studied extractants the proposed model, which is very sensitive to the errors of the partition coefficient determination, cannot support any version of extraction mechanism.  相似文献   

13.
14.
张适适  田红玉  孙宝国  彭娟  杨涵 《精细化工》2006,23(11):1125-1127
以脂肪醛与丙二酸为原料,通过Knoevenagel反应制备了(E)-3-烷烯羧酸,反应以二甲苯为溶剂,在回流条件下进行。考察了哌啶、吡啶及4-二甲氨基吡啶(DMAP)对反应产物的影响。结果表明,采用哌啶催化时,反应产率最高,可达70%左右,(E)-3-烷烯羧酸与副产物α,β-不饱和羧酸的摩尔比可达12/1以上;DMAP作催化剂,产率较低,在60%左右,反应选择性略高于哌啶;吡啶作催化剂时产率最低,反应选择性也最差,(E)-3-烷烯羧酸与副产物α,β-不饱和羧酸的摩尔比只有3/1。  相似文献   

15.
(E)-3-甲基-2-环十五烯酮的立体选择性合成   总被引:2,自引:0,他引:2  
以1,10-二溴癸烷、乙酰乙酸乙酯为原料,通过相转移催化缩合、粗产物不经分离,直接水解合成了麝香酮关键中间体2,15-十六烷二酮,收率78.6%。然后以TiC l4与不同的叔胺为催化剂,对2,15-十六二酮进行分子内羟醛缩合关环反应,成功合成了脱氢麝香酮,并确定了顺反异构的比例,实验表明,以TiC l4-i-Pr2NEt为关环催化剂环合收率为79.5%,顺反异构比例为1∶3,有较好立体选择性。产品用IR、MS1、HNMR进行了表征。  相似文献   

16.
Lures containing different amounts of (E)-10-dodecen-1-yl acetate and (E,E)-8, 10-dodecadien-1-yl acetate were formulated in natural rubber stoppers or polyethylene vials and tested in traps in the field to establish relative attractiveness to males of the pea moth,Cydia nigricana (F.), dose-response relationships, and the effects of weathering. Initially, both formulations of (E,E)-8,10-dodecadien-1-yl acetate were much more attractive than those of (E)-10-dodecen-1-yl acetate, but their activity diminished considerably after only 5 days in the field because an inhibitor was formed, and polyethylene formulations were not attractive after one week. However, lures containing (E)-10-dodecen-1-yl acetate, with or without antioxidants, in both rubber and polyethylene were still attractive after three months' exposure in the field and are therefore suitable for practical monitoring of pea moth populations.  相似文献   

17.
目的 构建和筛选既能稳定、高效表达SS融合蛋白,又能使这种融合蛋白保持良好的SS抗原性和高水溶性等特点的重组质粒。方法 用 BamH I/Xho I (B/X)和 BamH I/EcoR I(B/E)双酶切,将含有SS基因的片段由pThioHis A中切出,然后分别克隆到 pT7ZZa中的相应酶切位点,得到pSSB/X(短尾)和pSS-B/E(长尾)两个重组质粒,用常规表达技术在大肠杆菌中对其进行表达。结果 pSS-B/X和pSS-B/E两个重组质粒在宿主菌BL21(DE3)中均获得表达,pSS-B/X获得高效表达后融合蛋白占菌体总蛋白的30.6%。两个表达菌经超声裂解后电泳发现,SS-B/X-ZZ和SS-B/E-ZZ这两种融合蛋白基本为可溶性蛋白,沉淀中含量极低。二者均具有良好的抗原性,结论pSS-B/X重组质粒很有希望成为SS基因疫苗的候选质粒。  相似文献   

18.
Glycosyltransferase OGT catalyzes the conjugation of O-linked β-D-N-acetylglucosamine (O-GlcNAc) to Ser and Thr residues of the cellular proteins and regulates many key processes in the cell. Here, we report the identification of OGT as a ubiquitination target of HECT-type E3 ubiquitin (UB) ligase E6AP, whose overexpression in HEK293 cells would induce the degradation of OGT. We also found that the expression of E6AP in HeLa cells with the endogenous expression of the E6 protein of the human papillomavirus (HPV) would accelerate OGT degradation by the proteasome and suppress O-GlcNAc modification of OGT substrates in the cell. Overall, our study establishes a new mechanism of OGT regulation by the ubiquitin–proteasome system (UPS) that mediates the crosstalk between protein ubiquitination and O-GlcNAcylation pathways underlying diverse cellular processes.  相似文献   

19.
Electrochemical degradation of aqueous solutions containing 17β-estradiol (E2), concentrations range of 250-750 μg dm−3, has been extensively studied using boron-doped diamond (BDD) anode with a working solution volume of 250 ml under galvanostatic control. Cyclic voltammetric experiments were performed to examine the redox response of E2 as a function of cycle number. The effect of operating variables such as initial concentration of E2, applied current density, supporting medium (Na2SO4, NaNO3, and NaCl) and initial pH of the electrolyte (pH 2-10) were systematically examined and discussed. Electrolysis at high anodic potential causes complex oxidation of E2 that leads to form the final sole product as CO2. A pseudo first-order kinetics for E2 decay was found against varying applied current density. Also, kinetic analysis suggests that electrooxidation reaction of E2 undergo the control of applied current density. It was observed that electrolyte pH and supporting medium have a vital role on E2 degradation. From a comparison study with other anode materials such as platinum (Pt) and glassy carbon (GC), the superiority of the BDD anode was proved. Total organic carbon results have shown that almost complete mineralization could be accomplished at higher applied current density with specific electrical charge 22.5 × 10−2 A h dm−3. Mineralization current efficiency was comparatively lower with increasing applied current density.  相似文献   

20.
国家标准物质的研制不但要求样品均匀、稳定,而且要求标准物质定值方法的正确和不确定度评定的合理,因此,标准物质定值的准确和不确定评定的合理对标准物质的研制水平起到了至关重要的作用。邀请国内行业权威的15个实验室联合定值,分析不确定度的来源评定不确定度,研制GBW(E)130573门尼粘度标准物质。按照偏态系数和峰态系数、格拉布斯准则、科克伦法分别检验定值结果是否呈现正态分布、可疑值、等精度。经过检验统计分析,在99%的置信概率下,GBW(E)130573门尼粘度标准物质的定值结果为正态分布、无可疑值、等精度。GBW(E)130573在ML(1+4)100℃下的标准值为86.6±0.9。  相似文献   

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