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1.
在ZINDO方法基础上,按完全态求和(SOS)公式编制了计算分子二阶非线性光学系数βijk、βu的程序.研究了不同取代基在5,12-二硫杂-7,14-二氮杂-5,7,12,14-四氢并五苯侧环取代衍生物及相关化合物的结构、光谱和二阶非线性光学性质。结果表明:侧环上取代推、拉电于基团对增大二阶光学非线性都有利;分子共平面,共轭作用强,对增大二阶光学非线性有利.  相似文献   

2.
Journal of Solid State Electrochemistry - In this study, the potential of Si14Ge14 and B14P14 as anode electrodes in metal-ion batteries by using of the density functional theory was investigated....  相似文献   

3.
新型尼龙214,414,614,814,1014和1214的合成与表征   总被引:3,自引:0,他引:3  
张国胜  李勇进  颜德岳 《化学学报》2002,60(11):2078-2082
用熔融缩聚法基于十四碳二酸合成了一系列偶偶尼龙,包括尼龙2 14,4 14, 6 14,8 14,10 14,12 14。用红外光谱、元素分析、核磁共振、差示扫描热分析 、热失重分析、热机械分析、粘度法对合成尼龙的结构与性能进行了表征。同时还 初步研究了尼龙12 14的物理性能,发现其物理性能介于尼龙66和聚乙烯之间。  相似文献   

4.
Δ8(14)-14α-deoxy- and 14α-deoxy-14α-hydroperoxyecdysteroids were synthesized, the reduction of Δ8(14)-14α-deoxy-20-hydroxyecdysone diacetonide at treatment with complex hydrides of alkali metals was investigated, and the stereochemistry of the obtained 6-hydroxy derivative and its acetate was established.  相似文献   

5.
Numerous efforts towards synthesis of anticancer drug paclitaxel (Taxol(r), 1a) with improved activities led to the modification at 13-phenylisoserine side chain and different positions of its core structure-baccatin III 1c1. At the same time, the activities of searching new taxoids for starting materials of new semi-synthetic paclitaxel analogs from Taxus spp. plant have not ever been stopped. Among these taxoids, 14?-hydroxy-10-deacetylbaccatin III 22 and 13-acetyl-9-dihydrobaccatin III …  相似文献   

6.
Abstract

Die Betaine 30 und 5 zeigen im rotonenrauschentkoppelten 31P-NMR-Sgektrum jeweils Tripletts, die auf eine Kopplung mit dem 14N-Kern zurückzuführen sind. Durch 14N-NMR-Messungen wird dieses Koppelverhalten bestätigt. 14N- und 31P-chemische Verschiebungen der Betaine 3 und 4 gehen parallel. Die 14N-NMR-Daten der Betaine 4 stehen im Einklang mit einer Beteiligung der Dimethylamino-Gruppe an der Ladungsdelokalisierung.

In the proton decoupled “P-NMR spectra of the betaines 3, and 5 triplets are observed which arise from coupling with the 14N nucleus. 14N-NMR measurements confirm this coupling behaviour. 14N and “P chemical shifts of the betaines 3 and 4 run parallel. 14N-NMR data of the betaines 4 are in accord with a participation of the dimethylamino group in charge delocalization.  相似文献   

7.
Tetrakisdehydro[14]annuleno[14]annulene consisting of ‘acetylene-cumulene’ bisdehydro[14]annulene and Sondheimer's bishydro[14]annulene has been synthesized. It was found that a strong diatropicity was observed in the ‘acetylene-cumulene’ bisdehydro[14]annulene moiety, whereas diatropicity of another bisdehydro[14]annulene moiety shows marked decrease comparable with that of napthobisdehydro[14]annulene synthesized by Sondheimer.  相似文献   

8.
Inhaltsübersicht. Erstmals wurden klar durchscheinende, orange-farbene Einkristalle von Cs2Li14[Tb3O14] aus Cs2TbO3 und Li2O (Tb: Li = 1:5) dargestellt [550°C, 21 d, verschlossenes AuRohr]. Es liegt der K2Li14[Pb3O14]-Typ vor [Vierkreisdiffraktometerdaten, PW 1100, MoKä-Strahlung, 660 Io(hkl), R = 4,8%, Rw = 3,4%, Immm, a = 1293,5(8), b = 792,6(3), c = 740,4(3) pm, Z = 2, d = 4,65]. Ebenfalls neu wurde K2Li14[Zr3O14] in Form farbloser Einkristalle durch Tempern inniger Gemenge von K2O, Li2O und ZrO2 (K: Li: Zr = 1:4:1,5) dargestellt [900°C, 14 d, geschlossene Ni-Bombe] und röntgenographisch untersucht. Die Strukturverfeinerung [612 Io(hkl), Vierkreisdiffraktometerdaten, PW 1100, MoKα-Strahlung, R = 5,9%, Rw = 5,3%, Immm, a = 1244,6, b = 776,4, c = 724,3 pm, Z = 2] bestätigt die Isotypie mit K2Li14[Pb3O14]. Der Madelunganteil der Gitterenergie, MAPLE, Effektive Koordinationszahlen, ECoN, diese über Mittlere Effektive Ionenradien, MEFIR, wurden berechnet. Für die nun bekannten Vertreter dieses Typs wurde ein Isotypievergleich vorgenommen. New Compounds of the K2Li14[Pb3O14] Type: Cs2Li14[Tb8O14] and K2Li14[Zr3O14] For the first time Cs2Li14[Tb3O14] has been prepared as orange single crystals from Cs2TbO3 and Li2O (Tb: Li = 1:5) [550°C, 21 d, sealed Au-Tube]. Structure Refinement [four-circle diffractometer data, PW 1100, MoKα radiation, 660 Io(hkl), R = 4.8%, Rw = 3.4%, Immm, a = 1293.5(8), b = 792.6(3), c = 740.4(3) pm, Z = 2, d = 4.65] confirms isotypy with K2Li14[Pb3O14]. K2Li14[Zr3O14] has also been prepared as colorless single crystals from K2O, Li2O, and ZrO2 (K: Li: Zr = 1:4:1.5), [900°C, 14 d, closed Ni-cylinder] and investigated by x-ray [612 Io(hkl), four-circle diffractometer data, PW 1100, MoKα radiation, R = 5.9%, Rw = 5.3%, Immm, a = 1244.6, b = 776.4, c = 724.3 pm, Z = 2]. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, the latter derived from Mean Effective Fictive Ionic Radii, MEFIR, are calculated. A detailed comparison of the structures is carried out.  相似文献   

9.
Propoxur (Baygon®) is an insecticide with a broad spectrum of activity and a very low order of mammalian toxicity. Radiosynthesis of propoxur was performed by the reaction of acetyl-114C chloride and sodium azide to produce methyl isocyanate which then reacted with o-isopropoxyphenol at 100°C. A two compartment reaction tube with a break seal was utilized. Chromatographic procedures for isolating the N-methylcarbamates from their reaction mixtures are reported. Acetyl-1–14C chloride was prepared from thionyl chloride and sodium acetate-1–14C. Grignard reaction between methyl iodide and carbon –14 dioxide yielded acetic acid –14C which was neutralized by sodium hydroxide solution to give sodium acetate 1-14C.  相似文献   

10.
Abstract

14C virginiamycin, an antibiotic composed of two synergistic factors S and M, was required for metabolism and residue studies. 14C Factors S and M were separated from crude 14C virginiamycin and purified by semi-preparative normal phase HPLC followed by crystallization/precipitation. After chemical and radiopurity assays, the two factors were recombined in a 1:4 ratio to form purified 14C virginiamycin.  相似文献   

11.
5-苯基-3,5-二乙氧基-2(5H)-呋喃酮的晶体结构   总被引:1,自引:0,他引:1  
标题化合物C14H16O4的晶体结构用X-射线单晶衍射法测定。晶体属三斜晶系,P空间群,晶胞参数a =8.696(2), b=8.943(2) , c=9.379(2) ?, ( = 69.28(3), ( =76.67(3), ( =80.28(3)o, V=660.8(3) ? 3, Z=2, Mr=248.28, Dx=1.248 g/cm3, F(000)=264, μ(MoK()=0.0851 mm—1。晶体结构用直接法解出,经全矩阵最小二乘法对原子参数进行修正,最终的偏离因子为R=0.061, wR=0.089。标题化合物有2个环:呋喃酮环和苯环。由C(1),C(2),C(3),C(4),O(4)构成的五元呋喃酮环的5个原子较好地处于1个平面上,平均偏差为0.0078?。O(2),O(3) 两个原子与呋喃酮环共平面。呋喃酮环和苯环之间的两面角为79.39o。  相似文献   

12.
LMR spectra for v=1←0 transitions of 14N16O in X2Π1/2,3/2 states were observed at 5.6 μm and 5.4 μm of CO laser. Introducing the advanced isotopic molecular constant scaling function to Hund's case (a) diatomic structure model, these spectra were analyzed and fitted together with all reliable previous spectral data of 14N16O as well as 14N17O and 14N18O. A full set of precise molecular parameters and their vibrational dependencies have been determined with much higher precision (1 -2 orders for most parameters). Many of them have been obtained for the first time. Using isotopic scaling function, the molecular constants of 14N17O and 14N18O were deduced.  相似文献   

13.
季铵盐型双子表面活性剂C14-s-C14·2Br的聚集行为   总被引:1,自引:0,他引:1  
用1H NMR弛豫、2D NOESY研究了双子表面活性剂14-s-14胶束在重水溶液中的聚集行为. 1H NMR自旋-晶格、自旋-自旋弛豫实验表明, 联结基团质子及其邻近的亚甲基质子的运动受到严重限制, 表明这些质子形成胶束疏水核的壳层;而远离极性头的疏水质子的运动则相对自由, 说明其位于胶束的内部. 14-s-14系列(s=2, 3, 4)的弛豫实验结果还表明, 联结基团越短, 分子的碳氢链在疏水核中的排列越紧密. 与14-4-14的对应单链表面活性剂TTAB相比, 它们的分子运动更受限制. 14-4-14的2D NOESY 谱给出了与16-4-16类似的交叉峰信息, 这表明14-4-14同16-4-16一样, 形成了表面不平滑的球形胶束. 因此, 烷烃链的长短对胶束中分子的排列方式没有影响.  相似文献   

14.
Ionized14CO gas provides a rapid method for producing14C-labelled biomolecules. The apparatus consists of a high vacuum system in which a small amount of14CO is ionized by electron impact. The resulting species drift towards a target where they interact with the molecule of interest to produce14C-labelled compounds. Since the reaction time is only 2 minutes, the method is particularly promising for producing tracer biomolecules with short-lived11C at high specific activities. We have studied the applicability of the method to various classes of compounds of biological importance, including sterids, alkaloids, prostaglandins, nucleosides, amino acids and proteins. All compounds treated gave rise to14C addition and degradation products. Furthermore, for some compounds, chromatographic analysis in multiple systems followed by derivatization and crystallization to constant specific activity, indicated that carbon exchange may occur to produce the labelled, but otherwise unaltered substrate in yields of the order of 10–100 mCi/mol. More conclusive proof of radiochemical identity must await production of larger quantities of material and rigorous purification including at least two different chromatographic techniques. Supported by the Medical Research Council of Canada Grant MA-6137, and by the Banting Research Foundation.  相似文献   

15.
Zusammenfassung Beim Erhitzen von 14-Brom-codeinon-dimethylacetal (1) in absol. Methanol mit einer äquivalenten Menge Na2CO3 entstehen die drei isomeren Methoxycodeinon-acetale3, 4 und5 sowie die beiden Indolino-codeinonderivate6 und7. Die Strukturen und Konfigurationen der Verbindungen3–6 werden auf Grund der NMR- und IR-Spektren sowie durch Umwandlung in bekannte Verbindungen bewiesen.
The methanolysis of 14-bromo-codeinone dimethyl acetal
14-Bromocodeinone dimethyl acetal (1) reacts in methanol containing sodium carbonate (0.5 moles) to give the three isomeric methoxycodeinone acetals3, 4, and5 besides the indolino-codeinones6 and7. The structures and configurations of3–6 were established on the basis of NMR- and IR-spectroscopy and by conversion to known compounds.


Herrn Prof.E. Ziegler mit den besten Wünschen zum 60. Geburtstag gewidmet.  相似文献   

16.
Codeinone (3) was efficiently and directly converted to 14-hydroxycodeinone (1) by catalytic air oxidation in aqueous solution. A number of simple manganese and copper salts were identified to be effective catalysts, including MnSO4, KMnO4, and CuSO4. An appropriate reducing agent, such as sodium thiosulfate, is required in the reaction mixture presumably for the reduction of a detrimental peroxide intermediate. This discovery allows the more abundant codeine to be employed as the starting material for the synthesis of 14-hydroxylated opiate drugs without recourse to a thebaine-like intermediate. These discoveries were inspired from our study of microbial transformation of codeine to 14-hydroxycodeine by Mycobacterium neoaurum, where we found the actual 14-hydroxylation step is a chemical reaction rather than an enzymatic reaction, as previously believed.  相似文献   

17.
A facile, efficient and environment-friendly protocol for the synthesis of 14-aryl- or alkyl-14H-dibenzo[a,j]xanthenes has been developed by one-pot condensation of 2-naphthol with aliphatic and aromatic aldehydes in the presence of P2O5 or InCl3 as catalysts under solvent-free conditions. The present approach offers the advantages of clean reaction, simple methodology, short reaction time, high yield, easy purification, and economic availability of the catalyst.  相似文献   

18.
The synthesis of [14][14]metaparacyclophane, the first [m][n]metaparacyclophane ever known, is described. The reaction sequence began with the bis-chloromethylation of [14]paracyclophane in refluxing CS(2), which yielded a nonseparable mixture of 16,19- and 16,20-bis(chloromethyl)[14]paracyclophane in an 8:1 ratio. Acetolysis of these dichlorides gave the corresponding diacetate mixture from which the minor component 16,20-bis(acetoxymethyl)[14]paracyclophane was isolated and elaborated into the desired cyclophane via the disulfone of 2,15-dithia[16][14]metaparacyclophane and subsequent sulfur dioxide extrusion by a one-flask Ramberg-B?cklund reaction procedure followed by hydrogenation.  相似文献   

19.
Catalytic hydrogenation of a totally synthetic mixture of (±)-3-methoxy-14-methyl-14α-estra-1,3,5( 10), 9(11)-tetraen-17-one(1) and the corresponding 1,3,5(10),8-tetraen-17-one (2) gives a mixture of 14α-methyl-8β,9β-, -8α,9α-, and -8β,9α-estrones, which is converted into the 17β-hydroxy-mixtures. t-Butylation gives a separable mixture of the three isomers, of which (±)-17β-t-butoxy-3 methoxy-14-methyl-9β,14α-estra-1,3,5(10)-triene(6) is the major component. The corresponding 14α-methylestradiols are prepared. A practical synthesis of (±)-14-methyl-14α-estra-1,3,5(10), 6,8-pentaene-3,17β-diol(25) is described, and it is shown that DDQ dehydrogenation of 1,3,5(10),9(11)-tetraenes in this series leads exclusively to the corresponding 1,3,5(10),6,8,11-hexaenes, whereas that of 1,3,5(10),8-tetraenes gives only 1,3,5(10),6,8-pentaenes.  相似文献   

20.
The base induced deprotonation of H-14 of 7-triethylsilyl- (7-TES-) and 7-tert-butoxycarbonyl- (7-BOC-) protected 13-oxo-baccatins gave the corresponding enolates, which were selectively aminated with electrophilic nitrogen donors, such as azodicarboxylates and tosyl azide. In particular, tosyl azide gave the corresponding 7-BOC- and 7-TES-13-oxo-14β-azido-baccatin III. Alternatively, the last compound was prepared via NaN3 induced azidation of the 13-silyl enol ether of 7-TES-13-oxo-baccatin III under oxidative (cerium ammonium nitrate) conditions. The 13-silyl enol ether was obtained in a multistep process by DBU induced silylation of 7-TES-13-oxo-baccatin III. The 7-TES-13-oxo-14β-azido-baccatin III was used as a key intermediate for the synthesis of a new family of antitumour taxanes containing amino based functional groups at the C-14 position, such as: 14β-azido, 14β-amino, 14β-amino 1, 14-carbamate, 14β-amino 1, 14-thiocarbamate, and 14β-amino N-tert-butoxycarbonyl-1,14-carbamate.  相似文献   

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