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 0 毫秒
1.
孟鸿  花文廷 《有机化学》1998,18(2):153-156
用2,5-双-(间甲酰基苯基)-1,3,4-恶二唑和相应的二胺,经[2+2]缩合环化反应,合成了三个含二苯联恶二唑的新型大环多胺4、5和7以及5的钡络合物。  相似文献   

2.
Novel 1,3,4-oxadiazole-containing polyazomethines were synthesized by the polycondensation of diamines, 2,5-bis (m-aminophenyl)-1,3,4-oxadiazole (BMAO) and 2,5-bis (p-aminophenyl)-1,3,4-oxadiazole (BPAO), with aromatic dialdehydes, isophthalaldehyde and terephthalaldehyde, in m-cresol at 20°C. These polymers were yellow to orange in color and had reduced viscosities up to 1.13 dL/g and electric conductivity as high as 10?11?10?12 S cm?1. All the polyazomethines were insoluble in common organic solvents but dissolved in concentrated sulfuric acid. Thermogravimetry showed that thermal degradation started at around 400°C in air and nitrogen atmospheres. Doping with iodine markedly increased the conductivity and produced the black-colored semiconductive polyazomethines with a maximum conductivity of the order of 10?6 S cm?1. Electronic spectra of the undoped polymers indicated a large bathochromic shift of the absorption maxima due to C?N bonds of the monomer diamines (285 nm for BMAO and 315 nm for BPAO). This suggests that π-electrons of the polymers are extensively delocalized along the main chain.  相似文献   

3.
4.
4,5-Dihydro-1,3,4-benzotriazepines were obtained in good yields by intramolecular thermal cyclization of arylazoanils with methyl or ethyl groups in the ortho positions of the aromatic ring on the imine nitrogen.  相似文献   

5.
Conclusions We synthesized a 15-membered organophosphorus macrocycle with twophosphine oxide groupings and polyether units, and specifically 1,2,7,8-dibenzo-3,6-diphospha-3,6-dioxo-3,6-diphenyl-15-crown-5.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1930–1932, August, 1978.  相似文献   

6.
The synthesis and characterization of a new 24-membered tetramide macrocycle (6) related to Leigh's macrocycles and catenanes is reported. The replacement of p-xylylenediamine (Leigh) by m-xylylenediamine (this work) strongly modifies the geometry and properties of the new macrocycle. NMR spectroscopy (in DMSO?d6 solution) and X-ray crystallography have been used to characterize compound 6. The structural features in the crystal (conformational aspects and H-bonding) have been discussed comparatively to two similar macrocycles NEWHIJ and UJUNOC.  相似文献   

7.
A new condensed heterocyclic system, viz., 1,3,7,9-tetra-oxo-2,8-diphenyl-6-formylpyrimido [3,4-a]pyrimido[4,5-dloxazine, was synthesized, and its electronic and PMR spectra were recorded. Factors that affect the orientation of nucleophilic substitution in betaines of the pyrimidine series with aliphatic amines are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 993–995, July, 1980.  相似文献   

8.
A simple and highly efficient procedure has been proposed for the synthesis of heterocyclic and aromatic N-benzyl amines via reductive amination of substituted aromatic aldehydes in the presence of sodium tetrahydridoborate-acetic acid system generating reactive sodium triacetoxyhydridoborate.  相似文献   

9.
It is shown experimentally that in salts of dinitromethyl derivatives of aromatic and heterocyclic compounds the nitro groups are equivalent, and participate equally in anion formation. It is shown that both in the free state, and as an anion, the dinitromethyl group in aromatic and heterocyclic compounds has just the same spectral characteristics as in aliphatic compounds. These characteristics can be utilized for analytical purposes. The IR spectra do not reveal conjugation between the mono- or dinitromethyl group and the benzene ring. Judging by the UV spectra the benzene ring is not conjugated with the dinitromethyl anion. It is found that in the solid state 2-dinitromethylpyridine is an internal salt.  相似文献   

10.
任仲皎  蒋鄂  周红斌 《有机化学》1995,15(2):218-220
本文报道了多聚磷酸作用下芳香族羧酸和盐酸氨基脲生成2,5-二取代1,3,4-恶二唑的新方法 .  相似文献   

11.
硒芳香杂环化合物的微波固相合成   总被引:2,自引:2,他引:2  
许多含硒杂环化合物具有抗肿瘤、抗病毒等生物活性及超导性。微波技术由于能量利用率高,操作简便,无污染等优点,已在有机合成中得到了广泛的应用。本文采用微波辐射固相合成法合成了如下目标化合物:  相似文献   

12.
This review article describes the survey of literature regarding the variety of synthetic methods of 1,3,4-thiadiazoline and related compounds in the last seven years (2004–2010). The aim of the review is to find out different methods for the synthesis of thiadiazolines. These heterocyclics are majorly obtained from the cyclization reactions of thiosemicarbazone under the various conditions. From the literature studies it was found that major importance was given to their pharmaceutical significance i.e., regarding their biological activity against different fungal and bacterial strains.  相似文献   

13.
A new strategy for the synthesis of Buckybowls is presented and initial attempts to implement it are reported. This involves annulation of further rings onto polycyclic aromatic systems that prefer to be planar but have been "pre-bent" by the installation of a tether. Pyrenophane 2b reacts with TCNE and PTAD to give 1:1 and 1:2 adducts, respectively. The less strained pyrenophane 2c is unreactive toward TCNE but gives a 1:2 adduct with PTAD. Attempted electrophilic aromatic brominations of pyrenophane 2e under a variety of conditions were unsuccessful, as were attempts to brominate cyclophanediene 1c, the direct synthetic precursor of 2c. Tether cleavage and addition reactions occurred rather than substitution. In an effort to circumvent tether cleavage problems, [7]-, [8]- and [9](2,7)pyrenophanes 22b-d were prepared. However, attempted bromination and Friedel-Crafts acylations failed. Evidence for the fleeting existence of [6](2,7)pyrenophane 22a was also obtained. Comparison of structural data (X-ray and AM1 calculations) for the pyrenophanes 22a-d with their 1,n-dioxa analogues 2a-d indicates that the nature of the tether has a strong effect on the degree of bend in the pyrene moiety and this led to the identification of trioxapyrenophane 28 as the next target in the quest for increasingly bent pyrenes.  相似文献   

14.
The synthesis of N-acyl derivatives of aromatic α-amino acids 5 by the amidoalkylations of aromatic and heterocyclic compounds with glyoxylic acid amide adducts is described.  相似文献   

15.
A generalized method for synthesizing a wide variety of heterocyclic aromatic amine derivatives from nitriles by use of hydroxide catalysts is presented. Nitrile dimers (3-aminocrotononitrile and dicyandiamide) and a dimer analog (anthranilonitrile) react with monomeric nitriles in the presence of hydroxide to form respectively, aminopyrimidines, diaminotriazines and aminoquinazolines.  相似文献   

16.
17.
The PMR spectra of piazthiol, which is benzo[1,2-c]-[1,2,5]-thiodiazole, and of its- and-nitro, chloro, methyl and amino derivatives are investigated. The effects of these substituents on the chemical shift is in qualitative agreement with the like effects in the benzene series. The parameters of the corresponding PMR spectra are greatly dependent on the electrophilic action of the heterocyclic ring. It is shown that there is conjugation in the thiadiazole ring, although, however, it is much weakened compared with that existing in the benzene ring.For Part II see [10].The authors thank V. F. Bystrov for discussions, and for making the double resonance measurements with-methylpiazthiol in a JNM-C-60 spectrometer.  相似文献   

18.
In research towards high performance polymeric materials, two novel series of bismaleimide (BMI) resins based on 1,3,4-oxadiazole-containing monomers have been designed and prepared by the copolymeriziation reaction of 5-tert-butyl-1,3-bis[5-(4-maleimidophenyl)-1,3,4-oxadiazole-2-yl]benzene (Buoxd) or 4,4′-bis[5-(4-maleimidophenyl)-1,3,4-oxadiazole-2-yl]diphenyldimethylsilane (Sioxd) and 4,4′-bismaleimidodiphenylmethane (BMDM) in different feed ratios. The structures, thermal and dynamic mechanical properties of all the resulting BMI resins were carefully characterized by a combination of methods such as IR, DSC, TGA and DMA. Investigation of the copolymerization process has shown that with an increase of the weight ratio of Buoxd or Sioxd, melting transition temperature (Tm) of BMI monomer mixtures decreased and the exothermic polymerization temperature (Tp) increased. For all BMI monomer mixtures, a rapid polymerization process was observed in the early stage, as shown by the IR investigations. No glass transition was observed for the resulting BMI resins in the temperature range from 50 °C to 350 °C, indicating the formation of highly cross-linking networks. The initial thermal decomposition temperatures (Td) of the BMI resins were in the range of 477-493 °C in nitrogen and 442-463 °C in the air. Dynamic mechanical analysis (DMA) of the composites made of the BMI resins and glass cloth showed high bending modulus not only at room temperature (E′, 1.9-5.3 GPa) but also at high temperature, e.g., 400 °C (E′, 1.7-4.4 GPa).  相似文献   

19.
20.
The PMR spectra of piazthiol, which is benzo[1,2-c]-[1,2,5]-thiodiazole, and of itsα- andβ-nitro, chloro, methyl and amino derivatives are investigated. The effects of these substituents on the chemical shift is in qualitative agreement with the like effects in the benzene series. The parameters of the corresponding PMR spectra are greatly dependent on the electrophilic action of the heterocyclic ring. It is shown that there is conjugation in the thiadiazole ring, although, however, it is much weakened compared with that existing in the benzene ring.  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