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3 Hydroxybenzoic Acid

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Damian Pociecha – One of the best experts on this subject based on the ideXlab platform.

  • Bent-core liquid crystals with a 2-substituted 3Hydroxybenzoic Acid central core
    Liquid Crystals, 2017
    Co-Authors: Lenka Pallová, Michal Kohout, Jiří Svoboda, Vladimíra Novotná, Václav Kozmík, Damian Pociecha
    Abstract:

    ABSTRACTWe report the synthesis and study of the mesomorphic behaviour for a series of bent-core materials based on 2-substituted 3Hydroxybenzoic Acid as a central unit. Properties of the studied compounds are tuned by lateral substitution (F, Cl, CH3, NO2 and CN) in the position 2 of 3Hydroxybenzoic Acid and by the length of the terminal alkyl chain. All studied homologues exhibit at least one mesophase. Mesomorphic properties are established and compared with other 3-hyhroxybenzoic derivatives studied previously, with analogous orientation of ester linkages, laterally substituted at different position on the central core. The role of the substitution and the length of the terminal alkyl chain are discussed.

  • Bent-core liquid crystals based on 6-substituted 3Hydroxybenzoic Acid: the role of substitution and linkage group orientation on mesomorphic properties
    Liquid Crystals, 2016
    Co-Authors: Jiří Tůma, Michal Kohout, Jiří Svoboda, Vladimíra Novotná, Damian Pociecha
    Abstract:

    ABSTRACTWe have prepared and studied new series of bent-core liquid crystals based on laterally substituted 3Hydroxybenzoic Acid. The physical properties of the materials were tuned by the type of lateral substitution in the vicinity of the carboxylic unit. Further modification was achieved by reorientation of connecting ester linkages in the elongating side arms and by changing the length of terminal alkyl chains. The physical properties of the materials were determined by differential scanning calorimetry (DSC), polarising optical microscopy and for selected compounds by x-ray diffraction analysis. The introduction of fluorine as lateral substituent leads to the appearance of a lamellar or columnar mesophase. On contrary, methyl- or chlorine-substituted compounds are mostly crystalline. We have found a strong correlation between the size of the lateral substituent and the mesogenicity of the studied materials.

  • Bent-shaped liquid crystals based on 4-substituted 3Hydroxybenzoic Acid central core – Part II
    Liquid Crystals, 2016
    Co-Authors: Jiří Tůma, Michal Kohout, Jiří Svoboda, Vladimíra Novotná, Damian Pociecha
    Abstract:

    Hereby, we present synthesis and mesomorphic properties of bent-shaped liquid crystals with 3Hydroxybenzoic Acid central core. The mesomorphic properties were tuned by lateral substitution in the position 4 of the central unit and by the length of the terminal alkyl chains. For comparison, materials based on 4-fluoro and 4-methylresorcinol were prepared and studied. The mesomorphic properties of all compounds were analysed by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction. Depending on the molecular structure, the materials exhibited columnar, lamellar and nematic phases. The results for 3Hydroxybenzoic Acid central core are compared with 4-substituted resorcinol-based materials, taking into account also previously published derivatives. Unlike the naphthalene-based materials studied previously, the reversal of one ester linkage in the central unit (resorcinol versus 3Hydroxybenzoic Acid) exerts only slight changes in physical properties of these structurally rel…

Jiří Svoboda – One of the best experts on this subject based on the ideXlab platform.

  • Bent-core liquid crystals with a 2-substituted 3Hydroxybenzoic Acid central core
    Liquid Crystals, 2017
    Co-Authors: Lenka Pallová, Michal Kohout, Jiří Svoboda, Vladimíra Novotná, Václav Kozmík, Damian Pociecha
    Abstract:

    ABSTRACTWe report the synthesis and study of the mesomorphic behaviour for a series of bent-core materials based on 2-substituted 3Hydroxybenzoic Acid as a central unit. Properties of the studied compounds are tuned by lateral substitution (F, Cl, CH3, NO2 and CN) in the position 2 of 3Hydroxybenzoic Acid and by the length of the terminal alkyl chain. All studied homologues exhibit at least one mesophase. Mesomorphic properties are established and compared with other 3-hyhroxybenzoic derivatives studied previously, with analogous orientation of ester linkages, laterally substituted at different position on the central core. The role of the substitution and the length of the terminal alkyl chain are discussed.

  • Photosensitive bent-core liquid crystals based on methyl substituted 3Hydroxybenzoic Acid
    RSC Advances, 2017
    Co-Authors: Michal Kohout, Vladimíra Novotná, Mohamed Alaasar, Anna Poryvai, Silvio Poppe, Carsten Tschierske, Jiří Svoboda
    Abstract:

    Photosensitive liquid crystals are of contemporary interest not only from the scientific point of view but also for various applications. Herein we report the first photosensitive materials based on laterally substituted 3Hydroxybenzoic Acid. The molecular self-assembly of these new materials was characterized using different physical techniques including differential scanning calorimetry (DSC), X-ray diffraction (XRD) measurements, electro-optical investigations and dielectric spectroscopy. We show that the number and position of azo units with respect to the lateral substitution on the molecular core significantly influence mesomorphic properties of the materials. Based on the position of the substituent, either non-polar or polar smectic C phases are formed. The optimum combination of both the structural elements results in an achiral material which shows a broad polymorphism and exhibits a stable dark-conglomerate crystalline phase with macroscopically chiral domains at room temperature. The structure of this phase differs from the previously described fluid sponge-like distorted smectic phases as well as from helical nano-filament phases, thus, adding new information on the possible variations in the nanostructures of this kind of phase. Moreover, the photosensitivity of these materials has been studied using 1H NMR specspectroscopy.

  • Bent-core liquid crystals based on 6-substituted 3Hydroxybenzoic Acid: the role of substitution and linkage group orientation on mesomorphic properties
    Liquid Crystals, 2016
    Co-Authors: Jiří Tůma, Michal Kohout, Jiří Svoboda, Vladimíra Novotná, Damian Pociecha
    Abstract:

    ABSTRACTWe have prepared and studied new series of bent-core liquid crystals based on laterally substituted 3Hydroxybenzoic Acid. The physical properties of the materials were tuned by the type of lateral substitution in the vicinity of the carboxylic unit. Further modification was achieved by reorientation of connecting ester linkages in the elongating side arms and by changing the length of terminal alkyl chains. The physical properties of the materials were determined by differential scanning calorimetry (DSC), polarising optical microscopy and for selected compounds by x-ray diffraction analysis. The introduction of fluorine as lateral substituent leads to the appearance of a lamellar or columnar mesophase. On contrary, methyl- or chlorine-substituted compounds are mostly crystalline. We have found a strong correlation between the size of the lateral substituent and the mesogenicity of the studied materials.

Michal Kohout – One of the best experts on this subject based on the ideXlab platform.

  • Bent-core liquid crystals with a 2-substituted 3Hydroxybenzoic Acid central core
    Liquid Crystals, 2017
    Co-Authors: Lenka Pallová, Michal Kohout, Jiří Svoboda, Vladimíra Novotná, Václav Kozmík, Damian Pociecha
    Abstract:

    ABSTRACTWe report the synthesis and study of the mesomorphic behaviour for a series of bent-core materials based on 2-substituted 3Hydroxybenzoic Acid as a central unit. Properties of the studied compounds are tuned by lateral substitution (F, Cl, CH3, NO2 and CN) in the position 2 of 3Hydroxybenzoic Acid and by the length of the terminal alkyl chain. All studied homologues exhibit at least one mesophase. Mesomorphic properties are established and compared with other 3-hyhroxybenzoic derivatives studied previously, with analogous orientation of ester linkages, laterally substituted at different position on the central core. The role of the substitution and the length of the terminal alkyl chain are discussed.

  • Photosensitive bent-core liquid crystals based on methyl substituted 3Hydroxybenzoic Acid
    RSC Advances, 2017
    Co-Authors: Michal Kohout, Vladimíra Novotná, Mohamed Alaasar, Anna Poryvai, Silvio Poppe, Carsten Tschierske, Jiří Svoboda
    Abstract:

    Photosensitive liquid crystals are of contemporary interest not only from the scientific point of view but also for various applications. Herein we report the first photosensitive materials based on laterally substituted 3Hydroxybenzoic Acid. The molecular self-assembly of these new materials was characterized using different physical techniques including differential scanning calorimetry (DSC), X-ray diffraction (XRD) measurements, electro-optical investigations and dielectric spectroscopy. We show that the number and position of azo units with respect to the lateral substitution on the molecular core significantly influence mesomorphic properties of the materials. Based on the position of the substituent, either non-polar or polar smectic C phases are formed. The optimum combination of both the structural elements results in an achiral material which shows a broad polymorphism and exhibits a stable dark-conglomerate crystalline phase with macroscopically chiral domains at room temperature. The structure of this phase differs from the previously described fluid sponge-like distorted smectic phases as well as from helical nano-filament phases, thus, adding new information on the possible variations in the nanostructures of this kind of phase. Moreover, the photosensitivity of these materials has been studied using 1H NMR spectroscopy.

  • Bent-core liquid crystals based on 6-substituted 3Hydroxybenzoic Acid: the role of substitution and linkage group orientation on mesomorphic properties
    Liquid Crystals, 2016
    Co-Authors: Jiří Tůma, Michal Kohout, Jiří Svoboda, Vladimíra Novotná, Damian Pociecha
    Abstract:

    ABSTRACTWe have prepared and studied new series of bent-core liquid crystals based on laterally substituted 3Hydroxybenzoic Acid. The physical properties of the materials were tuned by the type of lateral substitution in the vicinity of the carboxylic unit. Further modification was achieved by reorientation of connecting ester linkages in the elongating side arms and by changing the length of terminal alkyl chains. The physical properties of the materials were determined by differential scanning calorimetry (DSC), polarising optical microscopy and for selected compounds by x-ray diffraction analysis. The introduction of fluorine as lateral substituent leads to the appearance of a lamellar or columnar mesophase. On contrary, methyl- or chlorine-substituted compounds are mostly crystalline. We have found a strong correlation between the size of the lateral substituent and the mesogenicity of the studied materials.

Vladimíra Novotná – One of the best experts on this subject based on the ideXlab platform.

  • Bent-core liquid crystals with a 2-substituted 3Hydroxybenzoic Acid central core
    Liquid Crystals, 2017
    Co-Authors: Lenka Pallová, Michal Kohout, Jiří Svoboda, Vladimíra Novotná, Václav Kozmík, Damian Pociecha
    Abstract:

    ABSTRACTWe report the synthesis and study of the mesomorphic behaviour for a series of bent-core materials based on 2-substituted 3Hydroxybenzoic Acid as a central unit. Properties of the studied compounds are tuned by lateral substitution (F, Cl, CH3, NO2 and CN) in the position 2 of 3Hydroxybenzoic Acid and by the length of the terminal alkyl chain. All studied homologues exhibit at least one mesophase. Mesomorphic properties are established and compared with other 3-hyhroxybenzoic derivatives studied previously, with analogous orientation of ester linkages, laterally substituted at different position on the central core. The role of the substitution and the length of the terminal alkyl chain are discussed.

  • Photosensitive bent-core liquid crystals based on methyl substituted 3Hydroxybenzoic Acid
    RSC Advances, 2017
    Co-Authors: Michal Kohout, Vladimíra Novotná, Mohamed Alaasar, Anna Poryvai, Silvio Poppe, Carsten Tschierske, Jiří Svoboda
    Abstract:

    Photosensitive liquid crystals are of contemporary interest not only from the scientific point of view but also for various applications. Herein we report the first photosensitive materials based on laterally substituted 3Hydroxybenzoic Acid. The molecular self-assembly of these new materials was characterized using different physical techniques including differential scanning calorimetry (DSC), X-ray diffraction (XRD) measurements, electro-optical investigations and dielectric spectroscopy. We show that the number and position of azo units with respect to the lateral substitution on the molecular core significantly influence mesomorphic properties of the materials. Based on the position of the substituent, either non-polar or polar smectic C phases are formed. The optimum combination of both the structural elements results in an achiral material which shows a broad polymorphism and exhibits a stable dark-conglomerate crystalline phase with macroscopically chiral domains at room temperature. The structure of this phase differs from the previously described fluid sponge-like distorted smectic phases as well as from helical nano-filament phases, thus, adding new information on the possible variations in the nanostructures of this kind of phase. Moreover, the photosensitivity of these materials has been studied using 1H NMR spectroscopy.

  • Bent-core liquid crystals based on 6-substituted 3Hydroxybenzoic Acid: the role of substitution and linkage group orientation on mesomorphic properties
    Liquid Crystals, 2016
    Co-Authors: Jiří Tůma, Michal Kohout, Jiří Svoboda, Vladimíra Novotná, Damian Pociecha
    Abstract:

    ABSTRACTWe have prepared and studied new series of bent-core liquid crystals based on laterally substituted 3Hydroxybenzoic Acid. The physical properties of the materials were tuned by the type of lateral substitution in the vicinity of the carboxylic unit. Further modification was achieved by reorientation of connecting ester linkages in the elongating side arms and by changing the length of terminal alkyl chains. The physical properties of the materials were determined by differential scanning calorimetry (DSC), polarising optical microscopy and for selected compounds by x-ray diffraction analysis. The introduction of fluorine as lateral substituent leads to the appearance of a lamellar or columnar mesophase. On contrary, methyl- or chlorine-substituted compounds are mostly crystalline. We have found a strong correlation between the size of the lateral substituent and the mesogenicity of the studied materials.

Lian Zhou – One of the best experts on this subject based on the ideXlab platform.

  • Genetic Interference Analysis Reveals that Both 3Hydroxybenzoic Acid and 4-Hydroxybenzoic Acid Are Involved in Xanthomonadin Biosynthesis in the Phytopathogen Xanthomonas campestris pv. campestris.
    Phytopathology, 2020
    Co-Authors: Xue-qiang Cao, Lian Zhou, Bole Jiang, Jiliang Tang, Bo Chen, Xing-yu Ouyang, Kai Song, Alan R. Poplawsky
    Abstract:

    A characteristic feature of phytopathogenic Xanthomonas bacteria is the production of yellow membrane-bound pigments called xanthomonadins. Previous studies showed that 3Hydroxybenzoic Acid (3-HBA) was a xanthomonadin biosynthetic intermediate and also, that it had a signaling role. The question of whether the structural isomers 4-HBA and 2-HBA (salicylic Acid) have any role in xanthomonadin biosynthesis remained unclear. In this study, we have selectively eliminated 3-HBA, 4-HBA, or the production of both by expression of the mhb, pobA, and pchAB gene clusters in the Xanthomonas campestris pv. campestris strain XC1. The resulting strains were different in pigmentation, virulence factor production, and virulence. These results suggest that both 3-HBA and 4-HBA are involved in xanthomonadin biosynthesis. When both 3-HBA and 4-HBA are present, X. campestris pv. campestris prefers 3-HBA for Xanthomonadin-A biosynthesis; the 3-HBA-derived Xanthomonadin-A was predominant over the 4-HBA-derived xanthomonadin in the wild-type strain XC1. If 3-HBA is not present, then 4-HBA is used for biosynthesis of a structurally uncharacterized Xanthomonadin-B. Salicylic Acid had no effect on xanthomonadin biosynthesis. Interference with 3-HBA and 4-HBA biosynthesis also affected X. campestris pv. campestris virulence factor production and reduced virulence in cabbage and Chinese radish. These findings add to our understanding of xanthomonadin biosynthetic mechanisms and further help to elucidate the biological roles of xanthomonadins in X. campestris pv. campestris adaptation and virulence in host plants.

  • Biosynthesis of the yellow xanthomonadin pigments involves an ATP-dependent 3Hydroxybenzoic Acid: acyl carrier protein ligase and an unusual type II polyketide synthase pathway.
    Molecular microbiology, 2018
    Co-Authors: Xue-qiang Cao, Lian Zhou, Jia-yuan Wang, Bo Chen, Yu Jin
    Abstract:

    Xanthomonadins are yellow pigments that are produced by the phytopathogen Xanthomonas campestris pv. campestris (Xcc). A pig cluster is responsible for xanthomonadin biosynthesis. Previously, Xcc4014 of the cluster was characterized as a bifunctional chorismatase that produces 3Hydroxybenzoic Acid (3-HBA) and 4-HBA. In this study, genetic analysis identified 11 genes within the pig cluster to be essential for xanthomonadin biosynthesis. Biochemical and bioinformatics analysis suggest that xanthomonadins are synthesized via an unusual type II polyketide synthase pathway. Heterologous expression of the pig cluster in non-xanthomonadin-producing Pseudomonas aeruginosa strain resulted in the synthesis of chlorinated xanthomonadin-like pigments. Further analysis showed that xanC encodes an acyl carrier protprotein (ACP) while xanA2 encodes a ATP-dependent 3-HBA:ACP ligase. Both of them act together to catalyse the formation of 3-HBA-S-ACP from 3-HBA to initiate xanthomonadin biosynthesis. Finally, we showed that xanH encodes a FabG-like enzyme and xanK encodes a novel glycosyltransferase. Both xanH and xanK are not only required for xanthomonadin biosynthesis, but also required for the balanced biosynthesis of extracellular polysaccharides and DSF-family quorum sensing signals. These findings provide us with a better understanding of xanthomonadin biosynthetic mechanisms and directly demonstrate the presence of extensive cross-talk among xanthomonadin biosynthetic pathways and other metabolic pathways.

  • The rice bacterial pathogen Xanthomonas oryzae pv. oryzae produces 3Hydroxybenzoic Acid and 4-Hydroxybenzoic Acid via XanB2 for use in xanthomonadin, ubiquinone, and exopolysaccharide biosynthesis.
    Molecular plant-microbe interactions : MPMI, 2013
    Co-Authors: Lian Zhou, Jia-yuan Wang, Tin-wei Huang, Shuang Sun, Gongyou Chen, Alan R. Poplawsky
    Abstract:

    Xanthomonas oryzae pv. oryzae, the causal agent of rice bacterial blight, produces membrane-bound yellow pigments, referred to as xanthomonadins. Xanthomonadins protect the pathogen from photodamage and host-induced perioxidation damage. They are also required for epiphytic survival and successful host plant infection. Here, we show that XanB2 encoded by PXO_3739 plays a key role in xanthomonadin and coenzyme Q8 biosynthesis in X. oryzae pv. oryzae PXO99A. A xanB2 deletion mutant exhibits a pleiotropic phenotype, including xanthomonadin deficiency, producing less exopolysaccharide (EPS), lower viability and H2O2 resistance, and lower virulence. We further demonstrate that X. oryzae pv. oryzae produces 3Hydroxybenzoic Acid (3-HBA) and 4-Hydroxybenzoic Acid (4-HBA) via XanB2. 3-HBA is associated with xanthomonadin biosynthesis while 4-HBA is mainly used as a precursor for coenzyme Q (CoQ)8 biosynthesis. XanB2 is the alternative source of 4-HBA for CoQ8 biosynthesis in PXO99A. These findings suggest that the roles of XanB2 in PXO99A are generally consistent with those in X. campestris pv. campestris. The present study also demonstrated that X. oryzae pv. oryzae PXO99A has evolved several specific features in 3-HBA and 4-HBA signaling. First, our results showed that PXO99A produces less 3-HBA and 4-HBA than X. campestris pv. campestris and this is partially due to a degenerated 4-HBA efflux pump. Second, PXO99A has evolved unique xanthomonadin induction patterns via 3-HBA and 4-HBA. Third, our results showed that 3-HBA or 4-HBA positively regulates the expression of gum cluster to promote EPS production in PXO99A. Taken together, the results of this study indicate that XanB2 is a key metabolic enzyme linking xanthomonadin, CoQ, and EPS biosynthesis, which are collectively essential for X. oryzae pv. oryzae pathogenesis.