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1.
We have synthesized a homologous series of azoesters consisting of a coumaryl moiety as the end group. Eleven derivatives of this series exhibit mesomorphism. The nematic mesophase is exhibited from ethyl homologue onward, while the smectic phase commences at the pentyl derivative and is exhibited along with the nematic phase up to the hexadecyl derivative. The N-I transition temperatures curves show the usual odd-even effect. All the compounds in this series are thermally stable and exhibit a wide mesomorphic range of nearly 120°C. Their thermal stabilities and other characteristics are discussed. 相似文献
2.
We have synthesized a homologous series of azoesters consisting of a coumaryl moiety as the end group. Eleven derivatives of this series exhibit mesomorphism. The nematic mesophase is exhibited from ethyl homologue onward, while the smectic phase commences at the pentyl derivative and is exhibited along with the nematic phase up to the hexadecyl derivative. The N-I transition temperatures curves show the usual odd-even effect. All the compounds in this series are thermally stable and exhibit a wide mesomorphic range of nearly 120°C. Their thermal stabilities and other characteristics are discussed. 相似文献
3.
S. I. Maksimenko N. S. Novikova R. V. Kondrat’eva V. E. Kuz’min L. N. Ognichenko M. Yu. Yarkova 《Russian Journal of Organic Chemistry》2007,43(12):1773-1780
New alkane-α,ω-diyl esters, propane-1,3-diyl and butane-1,4-diyl bis[4-(4-alkoxybenzoyloxy)-3-bromobenzoates], were synthesized and were found to form nematic mesophase. The effects of the lateral substituent and the length of the central and terminal hydrocarbon chains on the mesomorphic properties of butane-1,4-diyl bis[4-(4-alkoxybenzoyloxy)-3-bromobenzoates] were studied. Structural factors responsible for mesogenic properties of these compounds were determined by conformation analysis. 相似文献
4.
The reaction of 4-substituted phenols with 4-n-alkylcyclohexene-1-carbonyl chlorides, which differ in the position of their double bond in the ring, has yielded the corresponding esters. Investigation of their mesophoric properties including the electrooptic parameters of mixtures containing these compounds show that aryl esters of acids containing the double bond in the second position of the cyclohexene fragment are the most promising for use as components of liquid crystal mixtures. 相似文献
5.
Nopporn Thasana Vilailak Prachyawarakorn Sopchok TontoolarugSomsak Ruchirawat 《Tetrahedron letters》2003,44(5):1019-1021
A facile synthesis of aryl α-keto esters is reported involving the rearrangement of aryl cyanohydrin carbonate esters induced by the α-carbanion to the nitrile group generated by LDA. However, under similar conditions, an o-benzyloxycyanohydrin carbonate ester rearranged via a domino reaction leading to 2-phenylbenzofuran-3-carboxylic acid. 相似文献
6.
The synthesis of some aryl β-D-C-glycosides bearing long alkoxy chains (grafted on the carbohydrate moiety through the intermediate of an aromatic core) is described. Their mesomorphic properties (studied by microscopic observations under polarized light, DSC and X-ray diffraction) are presented. 相似文献
7.
Sie Tiong Ha Lay Khoon Ong Siew Ling Lee Hong Cheu Lin Yip Foo Win Siew Teng Ong 《中国化学快报》2010,21(6):637-640
<正>A homologous series of Schiff base esters,4-chlorobenzylidene-4'-n-alkanoyloxyanilines,containing even number of carbons at the end groups of the molecules(C_(n-1)H_(2n-1)COO-,n=4,6,8,10,12,14,16) were synthesized.The mesomorphic properties were investigated by differential scanning calorimetry(DSC) and polarizing optical microscopy(POM).It was found that the end groups of the molecules had an effect on the mesomorphic properties.n-Butanoyloxy was found non-mesogenic,whilst n-hexanoyloxy exhibited monotropic smectic phase.The higher members in this homologous series were enantiotropic smectogens. 相似文献
8.
Tao Ma Yan Feng Li Shu Jiang Zhang Feng Chun Yang Chen Liang Gong Jiu Jiang Zhao 《中国化学快报》2010,21(8):976-978
<正>A new aromatic diacid monomer containing pyridine unit,4-phenyl-2,6-bis[4-(4-carboxyphenoxy) phenyl]pyridine 3,was successfully synthesized in three steps,starting from 4-hydroxyacetophenone.The corresponding pyridine-containing polybenzimidazole was prepared via polycondensation of 3 with tetraaminodiphenyl ether(TADE) in poly(phosphoric acid)(PPA).The resulting polybenzimidazole exhibits excellent solubility,good thermal stabilities and high thermal resistance. 相似文献
9.
V. M. Potapov V. M. Dem'yanovich V. A. Khlebnikov 《Chemistry of Heterocyclic Compounds》1984,20(1):77-81
Tertiary amines of the pyridine series containing an -phenylethylamine residue have been synthesized. The IR spectra and circular dichroisms of these amines have been measured in the 400–200 nm interval, and an assignment of the bands has been made. It is suggested that the long-wave absorption band in the 315 nm region for N-methyl-N-[2-(pyridin-2-yl) ethyl]--phenylethylamine and the Cotton effect corresponding to it are due to an intramolecular CTC.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 92–96, January, 1984. 相似文献
10.
Sie Tiong Ha Lay Khoon Ong Siew Teng Ong Guan Yeow Yeap Joanna Pik Wan Wong Teck Ming Koh Hong Cheu Lin 《中国化学快报》2009,20(7):767-770
A new series of Schiff base esters,4-(dimethylamino)benzylidene-4'-alkanoyloxyanilines containing even number of carbons at the end group of the molecules(C_(n-1)H_(2n-1)COO,n = 6,8,10,12,14,16,18) were synthesized.The present compounds were monotropic liquid crystals.It was also found that the end groups of the molecules had effect on the mesomorphic properties. 相似文献
11.
Two homologous series of esters derived from Schiff's bases containing the 1,3,4-thiadiazole unit (series 3 and 5) were synthesized and their liquid crystalline properties investigated by optical microscopy and differential scanning calorimetry. Depending on the position occupied by the carbonyl group, the smectic A phase was observed in series 3 and nematic phase in series 5. 相似文献
12.
Two homologous series of esters derived from Schiff's bases containing the 1,3,4-thiadiazole unit (series 3 and 5) were synthesized and their liquid crystalline properties investigated by optical microscopy and differential scanning calorimetry. Depending on the position occupied by the carbonyl group, the smectic A phase was observed in series 3 and nematic phase in series 5. 相似文献
13.
Sie Tiong Ha Teck Ming Koh Guan Yeow Yeap Hong Cheu Lin Jun Kit Beh Yip Foo Win Peng Lim Boey 《中国化学快报》2009,20(9):1081-1084
A homologous series of Schiff base esters,6-methoxy-2-(2-hydroxy-4-alkanoyloxybenzylidenamino)benzothiazoles,comprising a benzothiazole moiety as the core was synthesized.All the members of this series exhibited an enantiotropic nematic phase. The azomethine linkage along with the lateral hydroxyl and terminal methoxyl groups were found to exert an effect on the mesomorphic properties. 相似文献
14.
J. Belmar 《Liquid crystals》1999,26(1):9-15
Thesyntheses of N-4-n-alkoxyphenyl-6-n-decyloxyquinoline-2-carboxamide(alkoxy=CnH2n+1O, n=4-10) and 4-n-alkoxyphenyl-6-n-decyloxyquinoline-2-carboxylate (n=4,6,8) are described along with the measurement of their physical properties using DSC and optical methods. The amides all show an enantiotropic smectic A phase while the esters show monotropic mesophases. A study of the structure/mesomorphic activity relationship is also described. 相似文献
15.
《Tetrahedron letters》1988,29(4):489-490
Pyrolysis of 2-(o-azidobenzyl)pyridine (3) gives 3H-1,2-diazepino[1,7-a]indole (5), in which the intermediate nitrene has expanded the pyridine ring. 相似文献
16.
M. A. Mikhaleva V. A. Savel'ev A. I. Pavlyuchenko M. F. Grebenkin V. P. Mamaev 《Chemistry of Heterocyclic Compounds》1986,22(9):994-1001
Some aryl 5-alkyl(and alkoxy)pyrimidine-2-carboxylates (I) and 5-alkylpyrimidinoyloxybenzoates (II) have been obtained. It has been found the former do not display mesomorphism, but the latter are nematic liquid crystals with a range over which the mesophase exists of 50–90C. The transition to the liquid crystal state in these compounds takes place at approximately the same temperatures as in their benzene analogues, but the thermal stability of the mesophase is somewhat less. Cyano-derivatives of pyrimidine effectively increase the value of the dielectric anisotropy of the matrix mixture, but they have a marked effect on its clarification temperature.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1228–1235, September,1986. 相似文献
17.
Eleftherios V. Tourasanidis George P. Karayannidis 《Journal of polymer science. Part A, Polymer chemistry》1999,37(14):2391-2399
A new homologous series of liquid crystalline (LC) polymethacrylates, the poly[ω-(2-phenoxycarbonyl-naphthalene-6-yloxy)alkyl methacrylate]s, in which the length of the alkyl spacer is varied between 3 and 12 methylene units, have been synthesized by free-radical polymerization. The prepared polymers were studied by IR and 1H-NMR spectroscopy, viscosity measurements, differential scanning calorimetry (DSC), and polarized microscopy. Polymers with 3 or 4 methylene units spacer were glassy in nature, whereas those with 5–12 methylene units spacer exhibited smectic behavior. The glass transition temperatures decrease on increasing spacer length. The isotropization temperatures and the corresponding transition entropies showed an odd–even effect, with the odd members exhibiting the higher values. This effect attenuates on increasing spacer length. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2391–2399, 1999 相似文献
18.
Ziyu Wang 《Tetrahedron letters》2007,48(41):7323-7326
A facile synthetic approach toward the steroidal saponins bearing an aromatic E ring was developed starting from the readily available spirostan saponin. 相似文献
19.
20.
A new class of diarylethenes bearing a pyridine unit has been firstly developed and their properties such as photochromism, fatigue resistance, and fluorescence have been discussed. The pyridine unit was connected directly to the central cyclopentene ring as one aryl moiety and availably participated in the photoinduced cyclization reaction even in the crystalline phase. All of these diarylethenes exhibited excellent photochromism, remarkable fatigue resistance, and notable fluorescence photoswitches both in solution and in poly(methylmethacrylate) films. Moreover, the different substituents had a significant effect on their properties. The results indicated that the electron-donating substituent could significantly enhance the cyclization quantum yield and depress the cycloreversion quantum yield while the electron-withdrawing group had a notable contribution to the cycloreversion quantum yield and fluorescence quantum yield for these diarylethenes. 相似文献