- Synthesis and characterization of bent-rod liquid crystals
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Two series of diesters with bend-rod shapes were synthesized and their thermal properties characterized by POM and DSC. The central group conformational mobility and polarity as well as the length of the mesogenic groups were varied in order to correlate these parameters with mesophase stability. Results indicate that series II diesters are enantiotropic and that their mesophase sensitivity to central group structural changes is limited.
- Del Rosso, Pablo,Hernandez, Sandra A.,Garay, Raul O.
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- Anisotropic and magnetic properties in non-metal and non-radical organic aggregates of tri-substituted phenyl derivatives
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A new series of tri-substituted phenyl derivatives containing an aromatic imine unit and biphenyl ester possessing various numbers of carbon atoms at the terminal alkoxy chain, OCnH2n+1 (n = 7-12), along with a lateral o-ethoxy substituent have been successfully prepared and characterised by CHN microanalysis along with spectroscopic techniques (FTIR, 1H- and 13C-NMR). The texture observation under polarized light revealed that all the soft condensed materials exhibited an enantiotropic nematic (N) phase. The current studies have shown that the mesomorphic behaviour is greatly influenced by the length of the alkoxy chains wherein the thermal stability of a tri-substituted phenyl derivative will decrease if the terminal alkoxy chain is increased from n = 7 to 12. For the first time, these materials which do not possess any magnetic species in their structure, demonstrate magnetic interaction through naked eye observation as well as quantitative measurement using a SQUID magnetometer.
- Tun Nur Iskandar, Nur Amanina Juniasari,Guan-Yeow, Yeap,Maeta, Nobuyuki,Ito, Masato M.,Nakamura, Yoshiyuki,Gas, Katarzyna,Sawicki, Maciej
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p. 210 - 217
(2019/12/25)
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- Photo and electrically switchable B7 mesophase exhibiting asymmetric bent-core liquid crystals
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The first bent-core liquid crystal materials with a photo-active azo linkage exhibiting the B7 mesophase are reported. The lower homologues of the bent-core compounds display the B1 phase and higher homologues show the B7 mesophase. The mesomorphic properties were characterized using polarized optical microscopy, differential scanning calorimetry and X-ray diffraction. The B7 phase of these materials establishes ferroelectric switching characteristics with anticlinic organization (SmCAPF) of the molecules in the layers. The bent-core molecules with an azo linkage are important for photoisomerization studies, which indicate trans to cis isomerization at 30 s, whereas the reverse processes take place over 40 s in chloroform.
- Srinivasan, Murugesan Vijay,Kannan, Palaninathan,Roy, Arun
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p. 1584 - 1590
(2013/06/04)
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- Total synthesis and structure-activity relationships of caspofungin-like macrocyclic antifungal lipopeptides
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The echinocandins represent a well-known class of macrocyclic antifungal lipopeptides that can be used for treatment of invasive fungal infections. Due to their complex chemical structures and synthetic difficulties, the structure-activity relationships (SARs) of them are still limited. A total synthetic approach was developed to synthesize structurally diverse caspofungin-like antifungal cyclic lipopeptides, allowing for systemically investigating their SARs. Most of the designed cyclic lipopeptides showed potent antifungal activities with broad spectrum. In particular, several compounds (e.g., 30a, 30e-h, 31a-d, 32c, and 33a,b) were more active in vitro against Candida albicans or Aspergillus fumigatus than caspofungin. The findings in this work indicated that the 'left' tripeptide segment of cyclic lipopeptide scaffold might be suitable for a hydrophilic structural motif, whereas the 'right' lipotripeptide segment was preferred as a hydrophobic core. The alkoxy-naphthoyl was found to be optimal side chain and alkyl length could affect the SARs of alkoxy-aroyl side chains.
- Yao, Jianzhong,Liu, Hongming,Zhou, Ting,Chen, Hai,Miao, Zhenyuan,Dong, Guoqiang,Wang, Shengzheng,Sheng, Chunquan,Zhang, Wannian
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supporting information; experimental part
p. 3074 - 3085
(2012/06/01)
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- Synthesis and optical properties of luminescent naphthalene-based liquid crystals
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Luminescent naphthalene-based liquid crystals were newly synthesized and changes of the luminescent color through the phase transitions were characterized. We prepared the compounds by combining naphthalene and known mesogenic cores, oxadiazole and fluoro
- Mori, Takeshi,Kijima, Masashi
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experimental part
p. 246/[572]-256/[582]
(2010/03/30)
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- Synthesis and mesomorphic properties of low molar mass phosphorus derivatives
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New liquid crystalline phosphorus derivatives were synthesized as a core model compound and/or a model compound of the component for semiflexible liquid crystalline polymers. Alkoxy, oligo ethylene oxide, or chiral moieties were introduced into the terminal group of rigid moiety in order to investigate the effect of the terminal group on the thermal properties of the phosphorus derivatives. A nematic phase appears for the phosphorus derivative with alkoxy moieties or oligo ethylene oxide chain, while a mesophase is observed for the phosphorus derivative with a chiral moiety. Some phosphorus derivatives were thermally stable until more than 300°C.
- Tokushige,Mihara,Koide
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- Cyclohexapeptidyl amine compounds
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Cyclohexapeptidyl amine compounds are disclosed of the formula: or its acid addition salt, wherein: R1is H or OH; R2is H or OH; R3is QCnH2nNRVRVI, QCnH2nNRVRVIRVII+Y?, or Q(CH2)1-3CRVIIIRIXNHRX. R4is H or OH; R5is H, OH or CH3; R6is H or CH3; RIis wherein Rais C1-C10alkyl; or (CH2)qNRbRcwherein Rband Rcare independently H, C1-C10alkyl or Rband Rctaken together are wherein Rdis C1-C16alkyl, phenyl or benzyl; RIIis H, C1-4alkyl or benzyl; RIIIis H, C1-4alkyl or benzyl; RIVis RIIand RIIItaken together as —(CH2)4— or —(CH2)5—; RVis H, C1-C4alkyl or benzyl; RVIis H, C1-C4alkyl or benzyl or RVand RVItogether is —(CH2)4— or —(CH2)5—; RVIIis H or C1-C4alkyl; RVIIIis H, (CH2)mH, (CH2)mOH, (CH2)mNH2or COX wherein X is NH2, OH or O(CH2)mH; RIXis H, (CH2)mH, or together with RVIIIis ═O (carbonyl); RXis H (except when RVIIIand RIXare H, C(═NH)NH2, C(═NH)CH2)0-3H, CO(CH2)0-3H, CO(CH2)mNH2, (CH2)2-4OH or (CH2)2-4NH2; Q is O or S; Y is an anion of a pharmaceutically acceptable salt each m is independently an integer from 1 to 3, inclusive; n is an integer from 2 to 4, inclusive; p is an integer from 1 to 2, inclusive and q is an integer from 2 to 4, inclusive.
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- Mesomorphic trigonal bipyramidal iron(0) isocyanide complexes
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The synthesis, characterization and mesomorphic properties of three series of isocyanides and their trigonal bipyramidal iron(0) complexes [Fe(CO)4(CNR)] (R= C6H4O(O)CC6H4C6H4OC(n)H2(n)+1, C6H4C(O)OC6H4C6H4OC(n)H2(n)+1, C6H4C6H4O(O)CC6H4OC(n)H2(n)+1, n = 6, 8, 10, 12) are described. The free isocyanides exhibit nematic and/or smectic A phases for shorter chains (n = 6, 8) and only smectic A phases for longer chains, except the isocyanides CNC6H4O(O)CC6H4C6H4OC(n)H2(n)+1 which melt with extensive decomposition and do not produce mesophases. Their coordination to give the iron complexes [Fe(CO)4(CNR)] produces a slight decrease of their transition temperatures. The iron isocyanide complexes prepared show only a smectic C phase. The relationship between the molecular structure of the complexes and their thermal behaviour is discussed.
- Coco, Silverio,Espinet, Pablo,Marcos, Eva
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p. 1297 - 1302
(2007/10/03)
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- Cyclohexapeptidyl propanolamine compounds
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Certain propanolamine compounds are described which have a cyclohexapeptidyl nucleus and which possess antibiotic activity with physical properties suitable for direct use in therapeutic compositions. A process for their preparation is also described.
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- Cyclohexapeptidyl aminoalkyl ethers
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There are disclosed compounds of the general formula STR1 wherein all substituents are defined herein. The compounds are useful as antibiotic and antifungal agents.
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- Carboxylate compounds, liquid crystal materials liquid crystal compositions and liquid crystal elements
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There is provided a carboxylic acid compound represented by the following formulae (I) to (IV): STR1 a liquid crystal material consisting of the carboxylic acid ester compound, a liquid crystal composition comprising the carboxylic acid ester compound, and a liquid crystal element using the carboxylic acid ester compound. There can be obtained advantages such as low operating temperature, high speed switching, very small electric power consumption, and high-stable contrast.
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- New chiral side chains for ferro- and antiferro-electric liquid crystals derived from the preen-gland wax of the domestic goose
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(2R,4R,6R,8R)-2,4,6,8-Tetramethyldecanoic acid and (2R,4R,6R,8R)-2,4,6,8-tetramethyldecanol, as well as the (2R,4R,6R,8R) and the (2S,4R,6R,8R) diastereomers of 4,6,8-trimethyldecan-2-ol, have been obtained from the preen-gland wax of the domestic goose.
- Heppke, Gerd,Loetzsch, Detlef,Morr, Michael,Ernst, Ludger
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p. 1993 - 1999
(2007/10/03)
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- Aza cyclohexapeptide compounds
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The present invention relates to aza cyclohexapeptide compounds of the formula (Seq ID Nos. 1-10) STR1 which may be useful as antibiotics, antifungal agents and for the treatment of Pneumocystis carinii infections.
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- Aza cyclohexapeptide compounds
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The present invention is directed to novel aza cyclohexapeptide compounds of the formula STR1 where all substituents are defined herein, which are useful as antifungal agents and for the treatment of Pneumocystis carinii infections. Compositions containing the compounds of the invention are also disclosed.
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- Synthesis and characterization of ferroelectric and antiferroelectric liquid crystals derived from (2S)-2-(6-hydroxy-2-naphthyl)propionic acid
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A new series of chiral materials, hexyl(2s)-2-(6-(-4-(4′-alkoxyphenyl)benzoyloxy)-2′-naphthyl) propionates (HmPBNP; m = 6-18) had been prepared and their liquid crystalline properties were investigated as a function of alkyl chain length. These chiral materials exhibited novel ferroelectric Sc* and antiferroelectric ScA* phases and a propensity to the formation of the ScA* phase was found at longer alkyl chain lengths (m = 10, 12-18). An odd-even effect of the threshold voltage as a function of alkyl chain length for compounds HmPBNP (m = 12-16) possessing antiferroelectricity was observed. Spontaneous polarization and transverse dipole moment were also measured and are discussed in terms of the elongated alkyl chain length.
- Wu,Chen,Chen,Wang,Shy,Hsiue
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- Semisynthetic Chemical Modification of the Antifungal Lipopeptide Echinocandin B (ECB): Structure-Activity Studies of the Lipophilic and Geometric Parameters of Polyarylated Acyl Analogs of ECB
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Echinocandin B (ECB) is a lipopeptide composed of a complex cyclic peptide acylated at the N-terminus by linoleic acid.Enzymatic deacylation of ECB provided the peptide "nucleus" as a biologically inactive substrate from which novel ECB analogs were generated by chemical reacylation at the N-terminus.Varying the acyl group revealed that the structure and physical properties of the side chain, particularly its geometry and lipophlicity, played a pivotal role in determining the antifungal potency properties of the analog.Using CLOGP values to describe and compare the lipophlicities of the side chain fragments, it was shown that values of >3.5 were required for expression of antifungal activity.Sercondly, a linearly rigid geometry of the side chain was the most effective shape in enhancing the antifungal potency.Using these parameters as a guide, a variety of novel ECB analogs were synthesized which included arylacyl groups that incorporated biphenyl, terphenyl, tetraphenyl, and arylethynyl groups.Generally the glucan synthase inhibition by these analogs correlated well with in vitro and in vivo activities and was likewise influenced by the structure of the side chain.These structural variations resulted in enhancement of antifungal activity in both in vitro and in vivo assays.Some of these analogs, including LY303336 (14a), were effective by the oral route of administartion.
- Debono, Manuel,Turner, William W.,LaGrandeur, Lisa,Burkhadt, Fred J.,Nissen , Jeffrey S.,et al.
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p. 3271 - 3281
(2007/10/02)
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- Tilt Angle Variation as a Function of Chain Length and Temperature in the Smectic C Phases of p,Alkoxyphenyl-p,Alkoxybenzoates
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The variation of the tilt angle with temperature in the smectic C phase has generally been shown to be non-existent or very slow for compounds or mixtures with the nematic-smectic C transition, while in the case of systems with the smectic A-smectic C transition, a relation between the steepness of this variation, near the transition, and the width of the smectic A domain has been observed.In this work, the variation of tilt angle in the smectic C phase is described for p-alkoxyphenyl-p-alkoxybenzoate homologous series, for which the evolution of polymorphism can be controlled systematically, by varying stepwise the length of the aliphatic chains, and for which large domains can be obtained for each type of phase sequence, nematic-, smectic A- and isotropic-smectic C.After completing the discussion made previously on the incidence of chain length on polymorphism, we confirm that the variation of tilt angle with temperature is slowest for compounds with intermediate chain lengths corresponding to the largest smectic A temperature range; this variation becomes continuously steeper when the smectic A domain becomes narrow.In addition, we show that the same description can be extended to the other types of phase sequences, by using the hypothesis of a virtual smectic A-smectic C transition above the observed nematic- or isotropic-smectic C transition.In fact, short chain lengths for homologues with a nematic/smectic C transition, or long chain lengths for homologues with an isotropic/smectic C transition, lead to an increase of the tilt angle at the phase transition and to a decrease of the amplitude of its variation with temperature; in our description, this behaviour corresponds to an increase of the temperature range between the real and virtual transitions.As a consequence, the homologues with very short and very long chain lengths show a quasi temperature-independent tilt angle, while the other homologues present a tilt angle variation similar to that observed for compounds exhibiting a smectic C/smectic A transition.This feature indicates that there is no need to distinguish between different types of smectic C phase.
- Heinrich, B.,Guillon, D.
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- Optically active alcohol and derivatives thereof, liquid crystal composition containing same and liquid crystal device
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Optically active compounds of general formulae STR1 wherein A is O or S, R1 is a hydrogen atom, an alkyl group having 1-22 carbon atoms, a hydroxy containing alkyl group, para-alkyl substituted phenyl, para-alkyl substituted biphenyl, hydroxyphenyl, hydroxybiphenyl or tosyl; R2 is an alkyl group having 2-8 carbon atoms; m is an integer of 0-5, n is 0 or 1, where when m=0, n is not 1; p is 0 or 1; q is 0 or 1; D and E are independently H or a halogen atom; R3 is a linear alkyl group having 1 to 22 carbon atoms; and * and ** are asymmetric centers.
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- Polypeptide compound and a process for preparation thereof
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A polypeptide compound having antimicrobial activity of the following general formula: STR1 wherein R1 is hydrogen or acyl group, R2 is hydroxy or acyloxy, R3 is hydroxysulfonyloxy, and R4 is hydrogen or carbamoyl, with proviso that R1 is not palmitoyl, when R2 is hydroxy, R3 is hydroxysulfonyloxy and R4 is carbamoyl, and a pharmaceutically acceptable salt thereof.
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- Novel halogen-containing ester compounds, and their intermediates, and method of producing the same as well as liquid crystal compositions containing the same and light switching elements
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This invention provides a novel halogen-containing ester compound represented by the following general formula (I): STR1 (wherein R is an alkyl group, A is selected from a single bond, --O--, --COO-- and --CO--, both of X and Y are halogen atoms or either one of X and Y is a halogen atom and the other is a hydrogen atom, each of m and n is 0 or 1, m+n=0 or 1, each of k and l is an integer of 1 or more, provide kl), a liquid crystal composition and a light switching element each containing the above compound as well as a novel fluorophenol compound represented by the following general formula (II): STR2 (wherein each of k and l is an integer of 1 or more, provided kl) as an intermediate for the synthesis of the above ester compound and a method of producing the same.
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- Alkanoyl ester compounds and their intermediates and method of producing the same
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This invention provides a novel alkanoyl ester compound represented by general formula (I): STR1 (wherein A is of --, --O--, STR2 B is STR3 l and m are 1 or 2 provided that both are not simultaneously 2, k and n are an integer of 1 or more, respectively, provided that k>n, and R is an alkyl group), a liquid crystal composition containing this compound, a novel alkanoylphenyl compound or a novel alkanoylbiphenyl compound as an intermediate for the production of the above compound, and a method of producing the same. These novel alkanoyl ester compounds are excellent in the stability against light and the like and can take a liquid crystal state at a wide temperature range. Particularly, these compounds form liquid crystals of ferroelectricity having a large spontaneous polarization and a fast response rate by introducing an optically active group into the compound, so that they develop a very excellent effect as a starting material for optoelectronics and its related elements.
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- Biphenyl esters and liquid crystalline mixtures comprising them
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Biphenyl esters of the formula STR1 wherein X is --CO--O-- or --O--CO-- and R1 and R2 each are alkyl or alkoxy of 1 - 8 carbon atoms, enlarge significantly the temperature range of the nematic phase of liquid-crystalline compositions without adversely affecting other properties.
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