Smectic A and smectic C materials: partially deuteriated chiral liquid crystals (S)-(-)-2-methylbuty 4-(4-(d13)-hexyloxyphenyl)benzoate and (S)-(-)-2-methylbutyl 4-(4-(d17)-octyloxyphenyl)benzoate

In order to study the difference in microscopic orientation of ferro- and antiferroelectric liquid crystalline molecules, we synthesized the partially deuteriated chiral compounds, (S)-(^-)-2-methylbutyl 4-(4-(d₁₃)-hexyloxy- and (S)-(^-)-2-methylbutyl 4-(4-(d₁₇)-octyloxy-phenyl)benzoates. Fundamental physical properties such as phase transition temperatures, spontaneous polarization and tilt angle were determined. Polarized FTIR measurements were also made to provide information on molecular structure and orientation.     

Smectic A and smectic C materials: partially deuteriated chiral liquid crystals (S)-(-)-2-methylbuty 4-(4-(d13)-hexyloxyphenyl)benzoate and (S)-(-)-2-methylbutyl 4-(4-(d17)-octyloxyphenyl)benzoate

In order to study the difference in microscopic orientation of ferro- and antiferroelectric liquid crystalline molecules, we synthesized the partially deuteriated chiral compounds, (S)-(^-)-2-methylbutyl 4-(4-(d₁₃)-hexyloxy- and (S)-(^-)-2-methylbutyl 4-(4-(d₁₇)-octyloxy-phenyl)benzoates. Fundamental physical properties such as phase transition temperatures, spontaneous polarization and tilt angle were determined. Polarized FTIR measurements were also made to provide information on molecular structure and orientation.     

Synthesis and characterization of new ferroelectric liquid crystals containing a (2S)-2-[6-(4-hydroxybiphenyl-4'-carbonyloxy)-2'- naphthyl] propionate mesogenic group and oligo(oxyethylene) spacers

Three series of ferroelectric liquid crystals containing a (2S)-2-(6-(4-hydroxybiphenyl-4'-carbonyloxy)-2'-naphthyl)propionate mesogenic group and oligo(oxyethylene) spacers were synthesized. These obtained liquid crystal compounds were characterized by NMR, differential scanning calorimetry (DSC), optical polarized microscopy (POM), and X-ray powder diffraction measurements. Some of these materials containing four phenyl rings of ester cores (i.e. -Ph-Ph-COO-naph-) and chiral heptyl tail exhibited a rich mesomorphic behaviour, a blue phase (BP), a cholesteric phase (Ch), a smectic A (S_A), a twist grain boundary A (TGB_A), and a chiral smectic C (S_C*) phase. Another series containing four phenyl rings of ester cores and chiral butyl and pentyl chain tails revealed only a S_A phase and a S_C* phase. Moreover, a crystal E phase was observed in the short spacer chain (n = 0 or 1) homologues of three series of compounds. Also, the mesomorphism properties were discussed as a function of spacer units, numbers of aromatic rings of core, and different terminal asymmetric moieties.     

Structural and temperature effects in the high-performance liquid chromatographic enantioseparation of 1-(alpha-aminobenzyl)-2-naphthol and 2-(alpha-aminobenzyl)-1-naphthol analogs

The enantiomers of 1-(alpha-aminobenzyl)-2-naphthol and 2-(alpha-aminobenzyl)-1-naphthol analogs were separated isothermally on a cellulose-tris-3,5-dimethylphenyl carbamate-based chiral stationary phase (Chiralcel OD-H), at 10 degrees C increments in the range of 5-35 degrees C, using n-hexane/2-propanol/diethylamine as mobile phase. The mobile phase composition and temperature were varied to achieve baseline resolutions in a single chromatographic run. The dependence of the natural logarithms of selectivity factors, In alpha, on the inverse of temperature, 1/T, was used to determine the thermodynamic data of the enantiomers. The thermodynamic data revealed that all the compounds in this study separate via the same enthalpy-driven chiral recognition mechanism.     

2-(9-蒽基)-2-甲氧基乙酸乙酯的高效液相色谱手性拆分

以键合在5 μm硅胶上的纤维素-三(二甲基苯基氨基甲酸酯)为色谱柱的手性固定相,采用高效液相色谱(HPLC)法对外消旋的2-(9-蒽基)-2-甲氧基乙酸乙酯进行了手性拆分.对影响2-(9-蒽基)-2-甲氧基乙酸乙酯拆分的三个重要因素:流动相组成、流速、色谱柱温度进行了研究.实验结果表明,在流动相组成为正已烷-异丙醇(94/6,V/V),流速1.0 mL/min,柱温20℃的条件下,2-(9-蒽基)-2-甲氧基乙酸乙酯对映体得到很好的分离,分离度为3.63.     

HPLC Enantioseparation of 1-(α-Aminobenzyl)-2-naphthol and 2-(α-Aminobenzyl)-1-naphthol Analogs on a β-Cyclodextrin-Based Chiral Stationary Phase

The enantiomers of 1-(α-aminobenzyl)-2-naphthol and 2-(α-aminobenzyl)-1-naphthol analogs were separated isothermally on a 3,5-dimethylphenylcarbamoylated β-cyclodextrin-based chiral stationary phase (Cyclobond DMP), with an n-hexane/alcohol modifier as mobile phase. Optimization of the separation was achieved by variation of combinations of the polar mobile phase additives ethanol and methanol. The nature and position of the α-aminobenzyl substituent of the 1- and 2-naphthol analogs influenced the retention and the selectivity.     

Mesomorphic properties of 2-acyloxy5-(4-alkoxyphenylazo)tropones, 2-acyloxy-5-(4-alkylphenylazo)tropones,and 2-acyloxy-5-(4-alkoxycarbonylphenylazo)tropones

Three series of mesomorphic 2-acyloxy-5-phenylazotropones with alkoxy, alkyl, and alkoxycarbonyl groups at C-4 on the phenyl ring were prepared. It was known that the corresponding 5-phenylazotropolone derivatives and their methyl ethers were not mesomorphic. 2-Acetyl-5-(4-hexyloxyphenylazo)tropone, however, shows a monotropic smectic A phase. Even an acetyl group is therefore able to induce a mesophase. The effects of terminal substitution of the tropone ring by groups such as alkoxy, alkoxycarbonyl, and alkyl on the clearing points are discussed.     

反相高效液相色谱法测定1-(对偶氮苯)-3-(5-氯-2-吡啶)-三氮烯

采用ZORBAX Ec lipse XDB-C8(4.6 mm i.d.×150 mm,5μm)色谱柱,乙腈流动相,流速0.70 mL.m in-1,检测波长407 nm,建立了测定1-(对偶氮苯)-3-(5-氯-2-吡啶)-三氮烯的反相高效液相色谱法.该方法线性范围0.5-8.0 mg.L-1,相对标准偏差为2.5%(c=5.0 mg.L-1,n=5),回收率在95.7%-105%之间.     

Polymesomorphism in a homologous series of 2-(4-alkoxyphenyl)-5-(4-methylphenyl)pyridines

A new series of 2-(4- n -alkoxyphenyl)-5-(4-methylphenyl)pyridines (CH C H C H NC HOC H , n 1-10) (APMPP), which are teraryl compounds containing a pyridine ring in n 2 m 1 the centre position of the rigid core, was synthesized and the phase transitions of the homologues were studied using DSC measurements, polarizing optical microscopy and miscibility tests with terephthalylidene-bis-4- n -pentylaniline (TBPA). Only a nematic phase was found for the shorter alkoxy homologues with n 4. The longer alkoxy homologues with n 4 showed the sequence of enantiotropic phase transitions CrG-SmF-SmC-SmA-N-I, while a monotropic CrH phase was observed for the n 5-10 homologues. Interestingly, the polymesomorphisms appear when n is larger than 4. 3 6 4 5 3 6 4     

Mesomorphic properties of 2-acyloxy5-(4-alkoxyphenylazo)tropones, 2-acyloxy-5-(4-alkylphenylazo)tropones, and 2-acyloxy-5-(4-alkoxycarbonylphenylazo)tropones

Three series of mesomorphic 2-acyloxy-5-phenylazotropones with alkoxy, alkyl, and alkoxycarbonyl groups at C-4 on the phenyl ring were prepared. It was known that the corresponding 5-phenylazotropolone derivatives and their methyl ethers were not mesomorphic. 2-Acetyl-5-(4-hexyloxyphenylazo)tropone, however, shows a monotropic smectic A phase. Even an acetyl group is therefore able to induce a mesophase. The effects of terminal substitution of the tropone ring by groups such as alkoxy, alkoxycarbonyl, and alkyl on the clearing points are discussed.     

一种合成聚(2-甲氧基-5-(2′-乙基-己氧基)-对苯乙炔)的新方法

聚对苯乙炔 (ＰＰＶ)及其衍生物是制备聚合物发光二极管的最重要的聚合物之一[1] .这主要是因为它们具有优越的电致发光性能 ,易于合成以及良好的环境稳定性[2 ] .而聚 (2 甲氧基 5 (2′ 乙基 己氧基 ) 对苯乙炔 ) (ＭＥＨ ＰＰＶ)由于其可溶性好 ,发光效率和亮度高 ,在电致发光领域广受关注 .现在有许多ＭＥＨ ＰＰＶ的多步化学合成方法以及电化学合成方法 .但是 ,这些方法常常产率低 ,成本高且产品不纯 .本文报道一种固 液两相反应一步合成分子量大、溶解性好的ＭＥＨ ＰＰＶ的新方法 .1　主要原料对甲氧基苯酚 (纯度≥ 98% ,Ａｌｄｒ…     

Synthesis of 2-(4-n-alkylphenyl)-5-n-alkylpyridines

New liquid-crystalline 2-(4-alkylphenyl)-5-alkylpyridines were synthesized by the reaction of 2-(4-alkylphenyl)-1-lithio-1, 2-dihydrophyridines with alkyl bromides. The compounds obtained have relatively low melting points and narrow temperature ranges of the existence of a nematic meso phase; the thermal stability of the meso phase is determined by the length of the alkyl group in the pyridine and benzene parts of the molecule.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1389–1391, October, 1985.     

High-performance liquid chromatographic determination of 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl)uracil and its metabolite (E)-5-(2-bromovinyl)uracil in serum.

A high-performance liquid chromatographic method was developed to assay 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl)uracil and its metabolite (E)-5-(2-bromovinyl)uracil in serum. The chloro analogue of the parent drug is used as internal standard. Human serum samples were assayed to establish the pharmacokinetic parameters. Acetonitrile, used as a protein precipitant, was evaporated to dryness and the residue, containing the analytes and internal reference, was dissolved in mobile phase prior to chromatographic analysis. The minimum quantifiable level was 0.02 micrograms of each analyte per ml of serum.     

Further studies on the anti-ulcerogenic effects of compound, 2-(E-2-decenoylamino)ethyl 2-(cyclohexylethyl) sulfide.

Tha anti-ulcerogenic mechanism of 2-(E-2-decenoylamino)ethyl 2-(cyclohexylethyl) sulfide (compd. III-1a) was investigated in various gastric defensive factors. Compound III-1a maintained the high molecular glycoprotein (relative content of Fr. I hexose) and accelerated hexosamine synthesis which were reduced by water immersion stress. But plaunotol did not have these actions. The lipid peroxide level in the gastric mucosa from water immersion stressed rat was lowered by the administration of compd. III-1a. Compound III-1a maintained prostaglandin E2 (PGE2) and PGI2 contents which were reduced in the early phase of the stress and accelerated PGs synthesis in the late phase of the stress. Furthermore, compd. III-1a maintained phospholipase A2 (PLA2) activity which was reduced by the stress. The plaunotol treated group showed the same tendency as the compd. III-1a treated group on the lipid peroxide level, PGE2 and PGI2 contents, and PLA2 activity, but the potency of plaunotol was less than that of compd. III-1a. Compound III-1a accelerated gastric cell proliferation in pyloric glands of hydrocortisone treated rats. Tetragastrin accelerated significantly the cell proliferation in fundic glands. The sucralfate treated group showed the same tendency as the compd. III-1a treated group but the potency of sucralfate was less than that of compd. III-1a. The results in the present study suggest that compd. III-1a has a protective action on gastric mucosa.     

Synthesis and ferroelectric properties of chiral swallow-tailed liquid crystals derived from (S)-2-[1-(2-ethylbutoxy)]propanol

(S)-2-[1-(2-Ethylbutoxy)]propanol was designed and synthesized as a chiral building block for the preparation of chiral liquid crystals. Its derivatives, the (S)-2-[1-(2-ethylbutoxy)]propyl 4-[4-(4-alkoxyphenyl)phenoyloxy]benzoates, EPmPPB (m = 8-12), were prepared and their mesomorphic phases investigated. The results showed that the chiral materials displayed enantiotropic SmA* and SmC* phases, while those with shorter alkyl chains (m = 8-10) displayed an additional unidentified SmX* phase. The switching current, spontaneous polarization, tilt angle, dielectric constant and electro-optical response for the materials in the ferroelectric SmC* phase were measured. The electro-optic responses of the materials in polyimide film-coated, homogeneously aligned cell exhibit thresholdless, V-shaped switching in the ferroelectric phase.     

New liquid crystal compounds ( )-4-[5-(2-Methylbutyl)-1,3-dioxan-2-yl]phenyl 4-alkoxybenzoate

New liquid crystal compounds, (+)-4-[5-(2-methylbutyl)-1,3-dioxan-2-yl] phenyl 4-alkoxybenzoates (5), were synthesized. The mesomorphic behaviour of these compounds is compared with that of (+)-4-(5-alkyl-1,3-dioxan-2-yl)-phenyl 4-(2-methylbutoxy)benzoates (6). While compounds 6 exhibited a chiral smectic C phase, the corresponding compounds 5 did not. This might mean that for the appearance of a chiral smectic C phase in these types of compounds, it is necessary that the carbonyl and the chiral groups exist at nearby positions. Transition temperatures to those isotropic state for compounds 5 were lower than those for compounds 6. This result is common in both cases of (+)-4-alkoxycarbonylphenyl-4-[5-(2-methylbutyl)-1,3-dioxan-2-yl]benzoates (7), and (+)-4-(2-methylbutoxy-carbonyl)phenyl 4-(5-alkyl-1,3-dioxan-2-yl)-benzoates (8).     

Colorimetric determination of zirconium with 1-(2-pyridylazo)-2-naphthol

A method is described for the determination of as little as 50 ppm of zirconium in uranium-fission element alloys and zinc magnesium-uranium-fission element alloys. Zirconium is extracted from a nitric acid-aluminium nitrate medium with dibutyl phosphate in toluene. The uranium co-extracted with the zirconium is removed by scrubbing with hydrochloric acid-ammonium thiocyanate solution. A portion of the organic phase is mixed with pyridine-toluene solution of 1-(2-pyridylazo)-2-naphthol to develop the colour.     

2-(2-甲基烯丙基)-3-(3-甲基-1,2-丁二烯基)环己-2-烯酮重排生成八元环化合物反应机理的理论研究

采用密度泛函理论B3LYP/6-31G(d,p)方法研究了2-(2-甲基丙烯基)-3-(3-甲基-1,2-丁二烯基)环己-2-烯酮重排生成八元环化合物在气相中的反应机理. 考虑了两条可能的反应途径: 途径1包含5个过程, 途径2包含两个过程. 从能量上看, 两条途径的决定速度步均是[1,5]氢迁移. 采用自洽反应场极化连续模型(PCM模型)和极化导体模型(CPCM模型)研究了反应体系在甲苯溶液中的溶剂效应. 结果表明, 气相和溶液中途径2均是较优途径, 并且甲苯对该反应的溶剂化效应不明显. 理论研究结果与实验观察结果一致, 并很好地解释了有关实验现象.     

Comparison of liquid chromatographic behaviors on N-methylimidazolium functionalized ZrO(2)/SiO(2)-4 and N-methylimidazolium functionalized SiO(2) stationary phases

A new stationary phase N-methylimidazolium functionalized ZrO(2)/SiO(2)-4 (Zr/SilprMim) has been prepared. The chromatographic property of this stationary phase is investigated by ion chromatography (IC) with inorganic and organic anions, and normal phase HPLC with basic compounds and hydroxybenzenes. The effects of pH and the strength of Lewis base of eluent on separation of anions are studied. This new stationary phase is also compared with a N-methylimidazolium functionalized SiO(2) stationary phase (SilprMim). The results show that this new stationary phase can be used in analysis of inorganic anions with great prospects. At the same time, successful separations of some organic anions can be obtained by using phosphate buffer solution as mobile phase. This new stationary phase also has a distinct advantage in the separation of basic compounds in normal phase. But due to the presence of Lewis acid sites on the surface of ZrO(2)/SiO(2)-4, Lewis bases such as hydroxybenzenes adsorb very strongly on this new stationary phase, and Lewis acid sites can be masked or modified by the eluent that contain Lewis base groups.     

2-Hydroxy-5-(ethanolamino)-3-(10'-Z-pentadecenyl)-1,4-benzoquinone, new microbial phase II metabolite of maesanin

The use of microbial models for biotransformation of the natural benzoquinone, maesanin (1), resulted in the isolation of an ethanolamine conjugate (5) from the culture broth of Debaryomyces polymorphus ATCC 20280. Metabolite 5 was characterized as 2-hydroxy-5-(ethanolamino)-3-(10'-Z-pentadecenyl)-1,4-benzoq uinone. The production of 5 represents a new type of phase II conjugation reaction in microbial systems. The results of preliminary mammalian metabolism of 1 in rats were inconclusive.