首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
以邻、间或对氨基苯甲酸和杯[8]芳烃为原料,经重氮化一偶联反应合成了新型有色邻、间或对羰基苯偶氮基杯[8]芳烃,产物的结构经元素分析,IR,UV-Vis和1H NMR表征,并研究了它们的生色原理和光谱性能,实验结果表明它们是一类新型指示剂和具有新型配位空腔的主体分子。  相似文献   

2.
The low-resolution (resolution: 0.6 nm) fluorescence spectra of fluorobenzene derivatives, o-, m- and p-fluorotoluene (o-, m- and p-FT) were observed to investigate intramolecular vibrational energy redistribution (IVR) under controlled electron impact. The o- and m-FT spectra mainly consisted of unstructured emission from optically inactive states (bath modes) populated through IVR. The p-FT spectrum consisted of structured emission from optically active states and unstructured emission. The high-resolution (resolution: 0.15 nm) fluorescence spectrum of p-FT was measured to estimate the fraction of the structured emission intensity to the total emission intensity. The IVR rate of p-FT under electron impact excitation was faster than that under laser excitation. The fraction did not depend on the incident energy of electrons from 20 to 200 eV, and thus the IVR acceleration is not attributable to breakdown of the Born approximation.  相似文献   

3.
Thermal polymerization of o-, m-, and p-pyridinecarbonitriles and their derivatives under the action of Friedel-Crafts catalysts and binary catalysts was studied. The characteristics of the resulting polymers were determined.  相似文献   

4.
MA Potopnyk  P Cmoch  S Jarosz 《Organic letters》2012,14(16):4258-4261
A convenient route to macrocyclic diamide-linked macrocyclic derivatives with a sucrose scaffold is presented. Reaction of sucrose based amines (o- and m-) with acid dichlorides afforded the monomeric macrocycles in excellent yields, while reaction of the p-amines also provided dimeric products.  相似文献   

5.
Quantum chemical calculations with relativistic effects were performed on the photodissociation of o-, m-, and p-bromofluorobenzene (o-, m-, and p-BrFPh) at 266 nm. The method of multistate second-order multiconfigurational perturbation theory in conjunction with spin-orbit interaction through complete active space state interaction was employed to calculate the potential energy curves for the ground and low-lying excited states of o-, m-, and p-BrFPh along their photodissociation reaction coordinates. The dissociation mechanisms with products of Br((2)P(3∕2)) and Br(?)((2)P(1∕2)) states were clarified with the computed potential energy curves and the surface crossings. The current calculations augmented previous theoretical investigations by including relativistic effects and resolved some differences of experimental assignment regarding the dissociation channels of o-, m-, and p-BrFPh.  相似文献   

6.
Methyl (2), ethyl (3), propyl (4), butyl (5), allyl (6), benzyl (7), o-, m-, p-xylyl (8-10), and alpha-phenylethyl (11) derivatives of arabinofuranosyluracil (1) were synthesized and their pharmacological effects in mice were examined by using hypnotic activity and synergism with pentobarbital as indices for the CNS depressant effects. At a dose of 2.0 micromol/mouse by intracerebroventricular injection, the values of mean sleeping time induced by 7-11 were 144, 154, 117, 33, and 34 min, respectively, whereas the alkyl (2-6) derivatives did not cause any hypnotic activity. N3-o-Xylylarabinofuranosyluracil (8) displayed the most potent hypnotic activity among the derivatives tested. Certain derivatives (6-11) significantly prolonged the pentobarbital-induced sleeping time compared to control. The present study indicated that substitution with benzyl and/or related groups on the N3-position of arabinofuranosyluracil produced CNS depressant effects.  相似文献   

7.
On the basis of the boron-masking strategy, new divalent cross-coupling modules have been designed for the efficient synthesis of boron-substituted oligoarenes. The modules, i.e., monoprotected o-, m-, and p-benzenediboronic acid derivatives, undergo highly selective Suzuki-Miyaura coupling with sp2 iodides, bromides, chlorides, and triflates, affording coupling products in which the protected boronyl groups are left intact.  相似文献   

8.
Dozzo P  Kasar RA  Kahl SB 《Inorganic chemistry》2005,44(22):8053-8057
Aldehydes have long served as important building blocks for synthetic chemists, and carboranyl aldehydes are no exception. Recent literature reports, for example, illustrate their application as intermediates in biomedicine, materials science, and basic organic chemistry. We report here new methods for the single-step preparation of C-monoformyl and C,C-diformyl derivatives directly from o-, m-, and p-carborane, as well as improved synthetic routes to homologated carboranyl aldehydes. Additionally, reductive amination is used to transform these aldehydes into a series of 2 degrees amines of alpha-amino acid esters.  相似文献   

9.
超声间接电氧化合成三种甲基苯甲醛   总被引:2,自引:0,他引:2  
阚显文  陶海升  杜俊  周运友  方宾 《有机化学》2003,23(11):1282-1285
以Mn(II)/Mn(III)为氧化还原媒质,间接电氧化合成了邻、间、对位甲基苯甲 醛。在电解和合成的过程中,分别施加了超声进行反应。实验结果表明,电解的电 流效率和邻甲基苯甲醛、间甲基苯甲醛的合成产率在超声的参与下有10%左右的提 高。优化了超声电解的条件,并探讨了超声与未超声时将二甲苯的三个异构体氧化 为相应醛的难易程度。  相似文献   

10.
Capillary gel electrophoresis (CGE) was successfully applied to the separation of optically active isomers and position isomers by incorporating a suitable cyclodextrin chiral selector in polyacrylamide gel. A commercially available ss-cyclodextrin (ss-CD) was used for enantioselectivity towards o-, m- and p-nitrobenzoic acid, o-, m- and p-hydroxybenzoic acid, o-, m- and p-toluic acid and the optical isomers of dansyl-D,L-leucine and R,S-1,1'-binaphthyl-2,2-dihydrogenphosphate. Especially the effect of organic solvents, such as acetonitrile, methanol, dimethylsulphoxide and others were examined in detail. The resolution varied to some extent with the addition of the organic solvent to the polyacrylamide gel and the running buffer solution. The possible mechanism has also been discussed. In addition, quantitative aspects of the separation of stereoisomers using CGE have been studied, showing that both the resolution and accuracy of the determinations were affected by the ratio of the enantiomers.  相似文献   

11.
Zusammenfassung Es werden die gemessenen Absorptionskurven von o-, m- und p-Amino-, o-, m- und p-Nitro-, sowie o- und p-Cyan-diphenyl in verschiedenen Lösungsmitteln wiedergegeben. Aus der Abhängigkeit der Absorptionsbanden von der Art und Stellung der Substituenten wird auf ihre Zugehörigkeit zum Benzolchromophor geschlossen.  相似文献   

12.
In the presence of NaY faujasite, dimethyl carbonate (MeOCO(2)Me, DMC) is a highly chemoselective methylating agent of functionalized anilines such as aminophenols (1), aminobenzyl alcohols (2), aminobenzoic acids (3), and aminobenzamides (4). The reaction proceeds with the exclusive formation of N-methylanilines without any concurrent O-methylation or N-/O-methoxy carbonylation side processes. Particularly, only mono-N-methyl derivatives [XC(6)H(4)NHMe, X = o-, m-, and p-OH; o- and p-CH(2)OH; o- and p-CO(2)H; o- and p-CONH(2)] are obtained with selectivity up to 99% and isolated yields of 74-99%. DMC, which usually promotes methylations only at T > 120 degrees C, is activated by the zeolite catalyst and it reacts with compounds 1, 2, and 4, at 90 degrees C. Aminobenzoic acids (3) require a higher reaction temperature (> or =130 degrees C).  相似文献   

13.
The electron-impact mass spectra of 5-aminoalkylmethyl-substituted cytosine and of their 1-N- o-(m- or p-)bromobenzyl-substituted derivatives are discussed. The influence of 5-aminoalkyl and 1-N-bromobenzyl substituents on the mode of mass fragmentation occurring upon electron impact ionization was demonstrated. The fragmentation pathways of all compounds and the characteristic ions in these spectra originating from the McLafferty rearrangement, RDA reactions and simple cleavages are presented.  相似文献   

14.
Summary A scheme has been proposed for the identification of some of the aromatic amines, viz., aniline, ethyl and methyl aniline, diethyl and dimethyl aniline, - and -naphthylamine, o-, m- and p-toluidine, o-, m- and p-anisidine, m- and p-phenetidine, o-, m- and p-phenylenediamine, carbazole, benzidine, o-tolidine, quinoline and iso-quinoline, p-xylidine and diphenylamine. It is based on the reaction of an aqueous persulphate solution with an alcoholic solution of the amine.
Zusammenfassung Eine systematische Identifizierung einiger aromatischer Amine aufgrund der Oxydation mit Persulfatlösung wird beschrieben. Folgende Verbindungen werden dabei berücksichtigt: Anilin, Äthyl- und Methylanilin, Diäthyl- und Dimethylanilin, - und -Naphthylamin, o-, m- und p-Toluidin, o-, m- und p-Anisidin, m- und p-Phenetidin, o-, m- und p-Phenylendiamin, Carbazol, Benzidin, o-Tolidin, Chinolin und Isochinolin, p-Xylidin und Diphenylamin.
  相似文献   

15.
Complexes of the type NiL2(SCN)2 (L = aniline, o-, m-, p-toluidine, o-, m-, p-anisidine and p-phenetidine) have been prepared and characterised by room temperature magnetic moments and infra-red spectral data (down to 250 cm?1) in the solid state. The thiocyanate is present as a bridging group and the metal atom is shown to be in a six-coordinate environment having an octahedral stereochemistry.  相似文献   

16.
Fused-ring electron acceptors have made significant progress in recent years, while the development of fully non-fused ring acceptors has been unsatisfactory. Here, two fully non-fused ring acceptors, o-4TBC-2F and m-4TBC-2F, were designed and synthesized. By regulating the location of the hexyloxy chains, o-4TBC-2F formed planar backbones, while m-4TBC-2F displayed a twisted backbone. Additionally, the o-4TBC-2F film showed a markedly red-shifted absorption after thermal annealing, which indicated the formation of J-aggregates. For fabrication of organic solar cells (OSCs), PBDB-T was used as a donor and blended with the two acceptors. The o-4TBC-2F-based blend films displayed higher charge mobilities, lower energy loss and a higher power conversion efficiency (PCE). The optimized devices based on o-4TBC-2F gave a PCE of 10.26 %, which was much higher than those based on m-4TBC-2F at 2.63 %, and it is one of the highest reported PCE values for fully non-fused ring electron acceptors.  相似文献   

17.
张书胜  梁丽  袁倬斌 《色谱》1999,17(1):52-54
在玻碳纤维微电极上研究了电解液中β-环糊精(CD)的浓度对邻、间、对苯二酚的循环伏安特性的影响,从实验结果和分子结构水平方面考察了β-CD与邻、间、对苯二酚的包结作用。研究结果表明,β-CD与邻、间、对苯二酚的包结作用强弱顺序为间苯二酚、邻苯二酚、对苯二酚。讨论了电泳缓冲液中ΝΗ4Cl,SDS,β-CD的浓度及pH值对邻、间、对苯二酚迁移时间的影响。建立了苯二酚异构体胶束电动毛细管色谱-玻碳微电极柱上安培检测分析方法,方法的回收率在98%~103%之间。  相似文献   

18.
Summary Study of the rates of polymerization of N-(o-, m-, and p-methoxyphenyl)- and N-(o-, m-, and p-ethoxy-phenyl)methacrylamides showed that the ortho isomers of these compounds, in which there is no association between the molecules, polymerize much more rapidly than their meta and para isomers, the molecules of which are associated through hydrogen bonds.  相似文献   

19.
A capillary zone electrophoresis method coupling square wave amperometric detection (SWAD) for the simultaneous determination of positional isomers of benzendiols (i.e. o-, m-, p-benzenediols) has been developed. Effects of several factors, such as the composition of the running buffer, the pH value, separation voltage, injection time and the potential applied to the working electrode, were investigated to acquire the optimum conditions. The efficacy of the boric acid and ascorbic acid in the running buffer were discussed. o-, m-, p-Benzendiols can be well separated within 8 min in a 50 cm length of 50 microm diameter fused-silica capillary at a separation voltage of +15 kV. Operated in a wall-jet configuration, a 100 microm Pt-disk electrode used as the working electrode exhibits good response for the analytes. The relation between peak current and analyte concentration was linear over two orders of magnitude with detection limits (S/N = 3) ranging from 0.5 to 1.5 microM for all analytes. The proposed method has been successfully applied to monitor the o-, m-, p-benzendiols contents in the environmental wastewater samples with satisfactory assay results.  相似文献   

20.
Tandem mass spectrometry has been applied to differentiate three sets of o-, m- and p-methyl, -methoxy and -nitro-substituted-6-phenyl-dibenzo(d,f)(1,3)dioxepines. Collision-induced dissociation (CID) experiments have been carried out on 2-phenylbenzo[b]furan fragment ions, which originate from the decomposition of the molecular ions after their EI-induced isomerization to spirocyclic structures. With the exception of m- and p-methylphenylbenzo[b]furan isomers, which display identical CID mass spectra, the three isomeric methoxy- and nitrophenylbenzo[b]furan fragment ions display very characteristic CID behavior which allows unequivocal differentiation of the 6-phenyl-dibenzo(d,f)(1,3)dioxepine isomers. 6-(o-nitrophenyl)-dibenzo(d,f)(1,3)dioxepine isomer, does not form a 2-(o-nitrophenyl)benzo[b]furan ion and, therefore, it can be differentiated from the m- and p- isomers based on the mere EI mass spectra. Furthermore, it shows a characteristic ion most likely due to an ortho effect between the nitro group and the dioxepine ring. Multiple stage mass spectrometric techniques (MSn), labeled derivatives and reference compounds were used in order to gain additional information on the structures of product ion from the CID fragmentation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号