Synthesis and Physical Properties of New Ferroelectric Liquid Crystals Consisting of 2(S)-[2 (S)-Methylbutyloxy] Propanol

New ferroelectric liquid crystals containing two chiral centers, 4-(4′-n-alkyloxyphenyl)phenyl 4-{2(S)-[2(S)-methylbutyloxy]propoxy}benzoate ( 4a-4f ) and 4 -(n-alkyloxy)phenyl 4-{4′-[2(S)-(2(S)-methylbutyloxy)propoxy]phenyl}benzoate ( 5a-5f ) were synthesized and their physical properties studied. A phase-transition sequence of C-Sc*-N*-I was observed in most cases. Some homologues of them, 4a-4d , possess monotropic Sc * phase. Not only the Sc* phase-transition temperature of 5a-5f is lower than that of the corresponding 4a-4f , but their Sc * phase-transition temperature range is also wider than the corresponding 4a-4f . The Sc * phase temperature range can be up to 48 °C. The spontaneous polarization of 8-28 nC/cm² and the electric rise time of 240-420 μs were measured in FLCs 4a-5f .     

Synthesis and properties of O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl cellulose

In this article, a series of O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl celluloses with different degree of substitution (DS) values was synthesized by a homogeneous reaction of cellulose with 2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl chloride in a 10% (w/w) dimethylacetamide/lithium chloride solution, combined with pyridine as the acid acceptor. The total DS values of the derivatives in anhydroglucose units was determined by ¹H and ¹³C NMR spectra, and ranged from 0.4 to 3.0, depending on the amount of acid chloride in the reaction. The effects of the total DS values and the O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl substituent distribution on the solubility of the derivatives were investigated. The lowest limit of the DS value for water‐soluble O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl cellulose was approximately 0.5, which is lower than that of methylcellulose. The amphiphilic derivatives with higher DS values than 1.7 exhibited a good solubility in both water and organic solvents, such as dimethyl sulfoxide, tetrahydrofuran, and chloroform. Sol‐gel transition in aqueous solution was observed for the amphiphilic derivatives with a higher DS value than 1.7; the precipitation temperature (T_p) decreased as the DS value increased, showing that the derivatives are highly temperature sensitive. The thermal properties of the fully substituted derivative were measured using polarized microscopy, DSC, and X‐ray diffraction; and are discussed in terms of phase transition of the sample derivatives. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 376–382, 2001     

Crystallographic report: Bis{µ‐[O‐cyclopentyl(4‐methoxyphenyl)dithiophosphonato]1κ:S,2κ:S‐[O‐cyclopentyl(4‐methoxyphenyl)dithiophosphonato]‐1κ2S,S′}dicadmium(II)

The centrosymmetric title compound, [Cd₂{CH₃OC₆H₄P(OC₅H₉)S₂}₄], features an eight‐membered [? Cd? S? P? S? ]₂ ring owing to the presence of bridging dithiolate ligands. Tetrahedral coordination geometries for cadmium are completed by chelating ligands. Copyright © 2004 John Wiley & Sons, Ltd.     

Helical Carbon and Graphite Films Prepared from Helical Poly(3,4‐ethylenedioxythiophene) Films Synthesized by Electrochemical Polymerization in Chiral Nematic Liquid Crystals

Helical carbon and graphite films from helical poly(3,4‐ethylenedioxythiophene) (H‐PEDOT) films synthesized through electrochemical polymerization in a chiral nematic liquid‐crystal (N*‐LC) field are prepared. The microscope investigations showed that the H‐PEDOT film synthesized in the N*‐LC has large domains of one‐handed spiral morphology consisting of fibril bundles. The H‐PEDOT films exhibited distinct Cotton effects in circular dichroism spectra. The highly twisted N*‐LC with a helical pitch of smaller than 1 μm produced the H‐PEDOT film with a highly ordered morphology. The spiral morphologies with left‐ and right‐handed screws were observed for the carbon films prepared from the H‐PEDOT films at 800 °C and were well correlated with the textures and helical pitches of the N*‐LCs. The spiral morphologies of the precursors were also retained even in the graphite films prepared from the helical carbon films at 2600 °C.     

Crystallographic report: Bis{µ‐[O‐cyclopentyl(4‐methoxyphenyl) dithiophosphonato]1κ:S,2κ:S‐[O‐cyclopentyl(4‐methoxyphenyl)dithiophosphonato]1κ2S,S′} dizinc(II)

The centrosymmetric [Zn₂{CH₃OC₆H₄P(OC₅H₉)S₂}₄], features an eight‐membered Zn₂S₄P₂ ring as a result of two bidentate bridging thiolate ligands; the remaining ligands are chelating. Copyright © 2005 John Wiley & Sons, Ltd.     

Crystallographic report: Chloro[1,3‐bis[2‐[2‐[(4‐methoxybenzyl) amino]ethylamino]]‐2‐propanol]zinc(II) chloride hydrate, [(C23H36N4O3)ZnCl]Cl·H2O

The zinc(II) center in the molecule of [(C₂₃H₃₆N₄O₃)ZnCl]Cl·H₂O is coordinated by four nitrogen atoms of HL (1,3‐bis[2‐[2‐[(4‐methoxybenzyl) amino]ethylamino]]‐2‐propanol) and one chloro anion. The coordination moieties are connected by hydrogen bonds to form a one‐dimensional structure. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis,Characterization, and DNA‐Binding Properties of the Chiral Ruthenium(II) Complexes Δ‐ and Λ‐[Ru(bpy)2(dmppd)]2+ (dmppd = 10,12‐Dimethylpteridino[6,7‐f] [1,10]phenanthroline‐11,13(10H,12H)‐dione; bpy = 2,2′‐Bipyridine)

Two novel chiral ruthenium(II) complexes, Δ‐[Ru(bpy)₂(dmppd)]²⁺ and Λ‐[Ru(bpy)₂(dmppd)]²⁺ (dmppd = 10,12‐dimethylpteridino[6,7‐f] [1,10]phenanthroline‐11,13(10H,12H)‐dione, bpy = 2,2′‐bipyridine), were synthesized and characterized by elemental analysis, ¹H‐NMR and ES‐MS. The DNA‐binding behaviors of both complexes were studied by UV/VIS absorption titration, competitive binding experiments, viscosity measurements, thermal DNA denaturation, and circular‐dichroism spectra. The results indicate that both chiral complexes bind to calf‐thymus DNA in an intercalative mode, and the Δ enantiomer shows larger DNA affinity than the Λ enantiomer does. Theoretical‐calculation studies for the DNA‐binding behaviors of these complexes were carried out by the density‐functional‐theory method. The mechanism involved in the regulating and controlling of the DNA‐binding abilities of the complexes was further explored by the comparative studies of [Ru(bpy)₂(dmppd)]²⁺ and of its parent complex [Ru(bpy)₂(ppd)]²⁺ (ppd = pteridino[6,7‐f] [1,10]phenanthroline‐11,13 (10H,12H)‐dione).     

Synthesis of New Chiral Calix [4] crown Containing (R)‐Cysteine

Three new chiral heterocalix [4] crowns containing aza thio atoms bearing two chiral sites provided by (R)‐cysteine ester were synthesized. All new compounds were characterized by ¹H NMR, MS and elemental analysis.     

Enantioselective determination of (R)‐ and (S)‐lansoprazole in human plasma by chiral liquid chromatography with mass spectrometry and its application to a stereoselective pharmacokinetic study

A simple and enantioselective method was developed and validated for the simultaneous determination of (R)‐ and (S)‐lansoprazole in human plasma by chiral liquid chromatography with tandem mass spectrometry. Lansoprazole enantiomers and internal standard (esomeprazole) were extracted from plasma using acetonitrile as protein precipitating agent. Baseline chiral separation was achieved within 9.0 min on a Chiralpak IC column (150 mm × 4.6 mm, 5 μm) with the column temperature of 30°C. The mobile phase consisted of 10 mM ammonium acetate solution containing 0.05% acetic acid/acetonitrile (50:50, v/v). The mass spectrometric analysis was performed using a QTrap 5500 mass spectrometer coupled with an electrospray ionization source in positive ion mode. The multiple reactions monitoring transitions of m/z 370.1→252.1 and 346.1→198.1 were used to quantify lansoprazole enantiomers and esomeprazole, respectively. For each enantiomer, no apparent matrix effect was found, the calibration curve was linear over 5.00–3000 ng/mL, the intra‐ and inter‐day precisions were below 10.0%, and the accuracy was –3.8 to 3.3%. Analytes were stable during the study. No chiral inversion was observed during sample storage, preparation procedure and analysis. The method was applied to the stereoselective pharmacokinetic studies in human after intravenous administration of dexlansoprazole or racemic lansoprazole.     

Chiral stationary phases based on chitosan bis(4‐methylphenylcarbamate)‐(alkoxyformamide)

Highly N‐deacetylated chitosan was chosen as a natural chiral origin for the synthesis of the selectors of chiral stationary phases. Therefore, chitosan was firstly acylated by various alkyl chloroformates yielding chitosan alkoxyformamides, and then these resulting products were further derivatized with 4‐methylphenyl isocyanate to afford chitosan bis(4‐methylphenylcarbamate)‐(alkoxyformamide). A series of chiral stationary phases was prepared by coating these derivatives on 3‐aminopropyl silica gel. The content of the derivatives on the chiral stationary phases was nearly 20% by weight. The chiral stationary phases prepared from chitosan bis(4‐methylphenylcarbamate)‐(ethoxyformamide) and chitosan bis(4‐methylphenylcarbamate)‐(isopropoxyformamide) comparatively showed better enantioseparation capability than those prepared from chitosan bis(4‐methylphenylcarbamate)‐(n‐pentoxyformamide) and chitosan bis(4‐methylphenylcarbamate)‐(benzoxyformamide). The tolerance against organic solvents of the chiral stationary phase of chitosan bis(4‐methylphenylcarbamate)‐(ethoxyformamide) was investigated, and the results revealed that this phase can work in 100% ethyl acetate and 100% chloroform mobile phases. Because as‐synthesized chiral selectors did not dissolve in many common organic solvents, the corresponding chiral stationary phases can be utilized in a wider range of mobile phases in comparison with conventional coating type chiral stationary phases of cellulose and amylose derivatives.     

Synthesis,Structure, and Properties of Cadmium(II) Centered Chiral Coordination Polymer based on (R)‐6‐(1‐Carboxyethoxy)‐2‐naphthoic Acid

A cadmium chiral coordination polymer, formulated as [Cd(R‐cna)]_n ( 1 ‐D) was constructed under hydrothermal method. Single‐crystal X‐ray diffraction analysis indicated that 1 ‐D exhibited a 2D layered structure with a point symbol of (4⁷ · 6³). 1 ‐D was further characterized by infrared spectra, powder X‐ray diffraction (PXRD), elemental analysis, thermogravimetric analysis (TGA), and circular dichroism spectra (CD). The second‐harmonic generation (SHG) property was investigated. It was also found that the luminescence of 1 ‐D can be quenched by iron ions and trinitrotoluene, indicating its potential application as luminescence sensing material.     

Neutral 4‐phenyl‐1‐[phenyl(pyridin‐2‐yl)methylidene]semicarbazide and its salt forms with inorganic anions

Semicarbazones can exist in two tautomeric forms. In the solid state, they are found in the keto form. This work presents the synthesis, structures and spectroscopic characterization (IR and NMR spectroscopy) of four such compounds, namely the neutral molecule 4‐phenyl‐1‐[phenyl(pyridin‐2‐yl)methylidene]semicarbazide, C₁₉H₁₆N₄O, (I), abbreviated as HBzPyS, and three different hydrated salts, namely the chloride dihydrate, C₁₉H₁₇N₄O⁺·Cl^?·2H₂O, (II), the nitrate dihydrate, C₁₉H₁₇N₄O⁺·NO₃^?·2H₂O, (III), and the thiocyanate 2.5‐hydrate, C₁₉H₁₇N₄O⁺·SCN^?·2.5H₂O, (IV), of 2‐[phenyl({[(phenylcarbamoyl)amino]imino})methyl]pyridinium, abbreviated as [H₂BzPyS]⁺·X^?·nH₂O, with X = Cl^? and n = 2 for (II), X = NO₃^? and n = 2 for (III), and X = SCN^? and n = 2.5 for (IV), showing the influence of the anionic form in the intermolecular interactions. Water molecules and counter‐ions (chloride or nitrate) are involved in the formation of a two‐dimensional arrangement by the establishment of hydrogen bonds with the N—H groups of the cation, stabilizing the E isomers in the solid state. The neutral HBzPyS molecule crystallized as the E isomer due to the existence of weak π–π interactions between pairs of molecules. The calculated IR spectrum of the hydrated [H₂BzPyS]⁺ cation is in good agreement with the experimental results.     

Enantiomers of a selective gelatinase inhibitor: (R)‐ and (S)‐2‐[(4‐phenoxyphenyl)sulfonylmethyl]thiirane

The compound 2‐[(4‐phenoxyphenyl)sulfonylmethyl]thiirane, C₁₅H₁₄O₃S₂, a selective gelatinase inhibitor, was synthesized and structurally characterized. Two crystals were analyzed, one each for the R and S enantiomers, and the results were compared with the previously reported structure of the racemate. The enantiomerically pure compounds both crystallize with Z′ = 2 in the space group P2₁, while the racemic mixture crystallizes with Z′ = 1 in the space group P2₁/c, with disorder in the position of the thiirane group. This disorder accommodates both molecules for each of the enantiomerically pure crystals, showing good overlap of the molecules of the pure enantiomorphs with the components of the centrosymmetric structure.     

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.     

Phosphorus NMR and Ab Initio Modelling of P–N Bond Rotamers of a Sterically Crowded Chiral β‐P4S3 Diamide

Reaction of bicyclic β‐P₄S₃I₂ with enantiomerically pure (R)‐Hpthiq (1‐phenyl‐1,2,3,4‐tetrahydroisoquinoline) and Et₃N gave a solution of a single diastereomer of the unusually stable diamide β‐P₄S₃(pthiq)₂, accounting for 83 % of the phosphorus content. Despite the steric bulk of the substituents, each amide group of this could adopt either of two rotameric positions about their P–N bonds, so that, at 183 K, ³¹P NMR multiplets for four rotamers could be observed and the spectra of three of them analysed fully. The large ²J(P–P–P) coupling became greater (253, 292, 304 Hz) with decreasing abundance of the individual rotamers. The rotamers were modelled at the ab initio RHF/3–21G* level, and relative NMR chemical shifts predicted by the GIAO method using a locally dense basis set, allowing the observed spectra to be assigned to structures. Calculations at the same level for the model compound α‐P₄S₃(pthiq)Cl confirmed the assignments of low‐temperature rotamers of α‐P₄S₃(pthiq)I reported previously. Changes in observed P–P coupling constants and ³¹P chemical shifts, on rotating a pthiq substituent, could then be compared between β‐P₄S₃(pthiq)₂ and α‐P₄S₃(pthiq)I, confirming both sets of assignments. The most abundant rotamer of β‐P₄S₃(pthiq)₂ was not the one with the least sterically crowded sides of both pthiq substituents pointing towards the P₄S₃ cage, because of interaction between the two substituents. Only by using a DFT method could relative abundances of rotamers of β‐P₄S₃(pthiq)₂ be predicted to be in the observed order. Use of racemic Hpthiq gave also the two diastereomers of β‐P₄S₃(pthiq)₂ with C_s symmetry, for which the room temperature ³¹P{¹H} NMR spectra were analysed fully.     

Chiral recognition in molecular and macromolecular pairs of (S)‐ and (R)‐1‐cyano‐2‐methylpropyl‐4′‐ {[4‐(8‐vinyloxyoctyloxy)benzoyl]oxy}biphenyl‐4‐ carboxylate enantiomers

(S)‐1‐Cyano‐2‐methylpropyl‐4′‐{[4‐(8‐vinyloxyoctyloxy)benzoyl]oxy}biphenyl‐ 4‐carboxylate [ (S)‐11 ] and (R)‐1‐cyano‐2‐methylpropyl‐4′‐{[4‐(8‐vinyloxyoctyloxy)benzoyl]oxy}biphenyl‐4‐carboxylate [( R)‐11 ] enantiomers, both greater than 99% enantiomeric excess, and their corresponding homopolymers, poly[ (S)‐11 ] and poly[ (R)‐11 ], with well‐defined molecular weights and narrow molecular weight distributions were synthesized and characterized. The mesomorphic behaviors of (S)‐11 and poly[ (S)‐11 ] are identical to those of (R)‐11 and poly[ (R)‐11 ], respectively. Both (S)‐11 and (R)‐11 exhibit enantiotropic S_A, S, and S_X (unidentified smectic) phases. The corresponding homopolymers exhibit S_A and S phases. The homopolymers with a degree of polymerization (DP) less than 6 also show a crystalline phase, whereas those with a DP greater than 10 exhibit a second S_X phase. Phase diagrams were investigated for four different pairs of enantiomers, (S)‐11 /( R)‐11 , (S)‐11 /poly[ (R)‐11 ], and poly[ (S)‐11 ]/poly[ (R)‐11 ], with similar and dissimilar molecular weights. In all cases, the structural units derived from the enantiomeric components are miscible and, therefore, isomorphic in the S_A and S phases over the entire range of enantiomeric composition. Chiral molecular recognition was observed in the S_A and S_X phases of the monomers but not in the S_A phase of the polymers. In addition, a very unusual chiral molecular recognition effect was detected in the S phase of the monomers below their crystallization temperature and in the S phase of the polymers below their glass‐transition temperature. In the S phase of the monomers above the melting temperature and of the polymers above the glass‐transition temperature, nonideal solution behavior was observed. However, in the S_A phase the monomer–polymer and polymer–polymer mixtures behave as an ideal solution. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3631–3655, 2000     

Preparation and Application of Cholesteryl‐Benzo‐15‐Crown‐5/Cholesteryl Mixed Liquid Crystals

Various mixed liquid crystals containing crown ether‐cholesteryl liquid crystal, benzo‐15‐crown‐5‐COO‐C₂₇H₄₅ (B15C5‐COOCh), with various common cholesteric liquid crystals, e.g., cholesteryl chloride, cholesteryl benzoate and cholesteryl palmitate, were prepared and studied using polarizing microscopy and differential scanning calorimetry. Investigating the concentration effect of B15C5‐COOCh in mixed liquid crystals revealed that the addition of B15C5‐COOCh resulted in wider phase transition temperature ranges of these cholesteryl liquid crystals. The stability of these B15C5‐COOCh/cholesteryl mixed liquid crystals was studied using comprehensive graphic molecular modeling computer programs (Insight II and Discover) to calculate their molecular energy and stability energy. The effect of salts, e.g. Na⁺, Co³⁺, Y³⁺ and La³⁺, on the transition temperature range of the mixed liquid crystals was also investigated. The crown ether cholesteric liquid crystal B15C5‐COOCh was applied both as a surfactant and an ion transport carrier to transport metal ions through liquid membranes. Cholesteryl benzo‐15‐crown‐5 exhibited distinctive characteristics of a surfactant and the critical micellar concentration (CMC) of the surfactant was investigated by the pyrene fluorescence probe method. Cholesteryl benzo‐15‐crown‐5 was successfully applied as a good ion transport carrier (Ionophore) to transport various metal ions, e.g. Li⁺, Na⁺, La³⁺, Fe³⁺ and Co³⁺, through organic liquid membranes. The transport ability of the cholesteryl benzo‐15‐crown‐5 surfactant for these metal ions was in the order: Co³⁺ ≥ Li⁺ > Fe³⁺ > Na⁺ > La³⁺.     

Reaktion von (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamin mit Me2MCl (M = Ga,In)

Reaction of (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamine with Me₂MCl (M = Ga, In) (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamine (H₂L) was reacted with Me₂GaCl and Me₂InCl in boiling toluene, respectively. In both cases the salt [Me₂M(H₂L)][Me₂MCl₂] [M = Ga ( 1 ), In ( 2 )] was formed. 1 and 2 were characterized by NMR and vibrational spectroscopy. In addition, an X‐ray structure determination was applied on 2 . According to the spectroscopical and structural findings 1 and 2 consist of cations [Me₂M(H₂L)]⁺ and anions [Me₂MCl₂]^?.     

Enantioselective determination of 1‐[4‐(2‐methoxyethyl)phenoxy]‐3‐[2‐(2‐methoxyphenoxy)ethylamino]‐2‐propanol hydrochloride,a novel antihypertensive agent,in rat plasma and tissues by liquid chromatography–tandem mass spectrometry

Enantioselective biodistribution studies of 1‐[4‐(2‐methoxyethyl)phenoxy]‐3‐[2‐(2‐methoxyphenoxy)ethylamino]‐2‐propanol hydrochloride (TJ0711), a novel antihypertensive agent, require the accurate and precise quantification of each TJ0711 enantiomer in biological fluids and tissues. Here we report a simple and sensitive liquid chromatography with tandem mass spectrometry method for simultaneous determination of (R )‐TJ0711 and (S )‐TJ0711 in rat plasma and tissue samples using protein precipitation. The influence of column type, temperature, mobile phase composition, and flow rate on the retention and enantioselectivity was evaluated. The separation of the TJ0711 enantiomers was ultimately achieved on a SUMICHIRAL OA‐2500 column in 15 min using isocratic elution with ethanol/hexane (40:60) at a flow rate of 0.8 mL/min. Good linearities of spiked analyte concentration from 5 to 2000 ng/mL were achieved and the correlation coefficients (R ) were greater than 0.99. The intra‐ and inter‐day accuracy and precision for both analytes were <15% at all concentration levels, and the extraction recoveries were consistent among the five quality control concentrations. This assay was successfully applied to quantify plasma and tissue concentrations of TJ0711 enantiomers in a preclinical study.     

Crystallographic report: Tris{2‐[2‐(1‐methyl)imidazolyl]methyliminoethyl}aminezinc(II) dihexafluorophosphate

The cation in the title compound has crystallographic threefold symmetry. The zinc atom is in a distorted octahedral geometry, being coordinated by three nitrogen atoms of the imine and three nitrogen atoms of imidazole. Copyright © 2004 John Wiley & Sons, Ltd.