Search

A pair of zinc(II)-based one-dimensional (1D) homologous coordination polymers, [Zn(Hdba)2(bib)]n (1) and [Zn(Hdba)2(bmib)]n (2), where H2dba = 3-hydroxybenzoic acid, bib = 1,4-bis(1-imidazolyl)benzene, and bmib = 1,4-bis(2-methyl-1H-imidazol-1-yl)benzene were hydrothermally synthesized and characterized through infrared spectroscopy (IR), elemental and thermal analysis (EA), powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction (SCXRD) analyses. The results revealed that 1 and 2 have the same zigzag infinite chain framework through the partially deprotonated Hdba– monodentate linkage and with μ2-bib bridging the Zn(II) atoms in 1, and with μ2-bmib bridges for the Zn(II) atoms in 2. For both 1 and 2, each zinc atom has a slightly twisted tetrahedral configuration with a N2O2 donor set. These chains of 1 and 2 are further connected into three-dimensional (3D) supramolecular structures through O–H···O, C–H···O hydrogen bonds and π···π, C–H···π stacking interactions for 1, and O–H···O, C–H···O hydrogen bonds for 2. Topologically, the 3D hydrogen-bonded organic framework or the 2D π-stacking structure of 1 can be simplified as a 4-connected dia Diamond type with a Schläfli symbol {66}, or as a 4-connected sql type with a Schläfli symbol {44·62} and a Shubnikov tetragonal plane net. The thermal stability and the solid-state fluorescence properties of 1 and 2 were investigated. [ABSTRACT FROM AUTHOR]

• The endophyte, Diaporthe sp. was isolated from Simarouba glauca for the first time. • Inhibition of α-glucosidase by endophytic fungal extract was superior to acarbose. • AGI active fraction had 3-hydroxybenzoic acid (3HBA) as a major compound. • Binding energy of 3HBA against yeast and human AG was good than the other compounds. • By satisfying the ADME/Toxicity rules, 3HBA could emerge as a potent AG inhibitor. Exploring new bioactive compounds from endophytic fungi with the anticipation of novel alpha-glucosidase inhibitors (AGIs) has led to the identification of few interesting small compounds. In the present study, the major chunk of purified fraction ('DFR8': Diaporthe sp. Fraction number 8) had a compound 3-hydroxybenzoic acid (compound 4), reported for the first time in an endophytic fungus Diaporthe sp. isolated from a medicinal plant, Simarouba glauca DC. The fraction ('DFR8') was purified from ethyl acetate extract of Diaporthe sp. using the activity-based column purification method, and the fraction showed the highest AG inhibition (IC 50 = 22.85 μg/mL). The fraction also showed significant antioxidant properties (DPPH: IC 50 =206.60 µg/mL and ABTS: IC 50 =59.65 µg/mL) and contained phenolic compounds. Apart from compound 4 , the GC–MS analysis of 'DFR8' revealed the presence of 16 other compounds at lesser concentrations, and some of them are already known for their antioxidant and alpha-glucosidase inhibition (AGI) activities. Interestingly, compound 4 (3-hydroxybenzoic acid) had the highest binding energy against both yeast and human AG enzymes when compared to the remaining compounds. Additionally, 3-hydroxybenzoic acid obeyed the crucial rules of drug-likeness properties during ADME/Toxicity evaluations, indicating that the compound could be developed into an effective AG inhibitor, which needs further detailed investigations. [ABSTRACT FROM AUTHOR]

• Two new cocrystals of berberine chloride (BCl) were discovered. • Bulk powders of both cocrystals were prepared and characterized. • The BCl-3HBA cocrystal exhibits faster dissolution over the commercial dihydrate. • BCl-3HBA is a suitable solid form for tablet development of BCl. In this study, two novel salt-cocrystals of berberine chloride (BCl) with structurally similar benzene derivatives, i.e., 3-hydroxybenzoic acid (3HBA) and isophthalic acid (IA), were prepared. Their solid-state properties were characterized by complementary techniques, including single-crystal and powder X-ray diffractometry, thermogravimetric-differential scanning calorimetry, Fourier-transformed infrared spectroscopy, and dynamic moisture sorption analysis. Both cocrystals had lower hygroscopicity than BCl. An analysis of the properties of these cocrystals along with a previously published berberine chloride-resorcinol cocrystal suggests that a greater number of hydroxyl groups in these cocrystal formers may favor faster dissolution, measured by both intrinsic dissolution rate and powder dissolution. [Display omitted] [ABSTRACT FROM AUTHOR]

The aroxyalkylaminoalcohol derivatives are a group of compounds known for their pharmacological action. The crystal structures of four new xylenoxyaminoalcohol derivatives having anticonvulsant activity are reported, namely, 2‐{[2‐(2,6‐dimethylphenoxy)ethyl]amino}‐1‐phenylethan‐1‐ol, C18H23NO2, 1, the salt N‐[2‐(2,6‐dimethylphenoxy)ethyl]‐1‐hydroxy‐1‐phenylethan‐2‐aminium 3‐hydroxybenzoate, C18H24NO2+·C7H5O3−, 2, and two polymorphs of the salt (R)‐N‐[2‐(2,6‐dimethylphenoxy)ethyl]‐1‐hydroxy‐1‐phenylethan‐2‐aminium chloride, C18H24NO2+·Cl−, 3 and 3p. Both polymorphs crystallize in the space group P21212 and each has two cations and two anions in the asymmetric unit (Z′ = 2). The molecules in the polymorphs show differences in their molecular conformations and intermolecular interactions. The crystal packing of neutral 1 is dominated by intermolecular O—H...N hydrogen bonds, resulting in the formation of one‐dimensional chains. In the crystal structures of the salt forms (2, 3 and 3p), each protonated N atom is engaged in a charge‐assisted hydrogen bond with the corresponding anion. The protonation of the N atom also influences the conformation of the molecular linker between the two aromatic rings and changes the orientation of the rings. The crystal packing of the salt forms is dominated by intermolecular O—H...O hydrogen bonds, resulting in the creation of chains and rings. Structural studies have been enriched by the calculation of Hirshfeld surfaces and the corresponding fingerprint plots. [ABSTRACT FROM AUTHOR]

This work describes the construction of a genosensor based on a graphite electrode modified with an reduced graphene oxide/poly(3‐hidroxybenzoic acid) nanocomposite with an specific DNA oligonucleotide for detection of cattle mitochondrial DNA, in order to certify beef purity. Electrochemical and morphological analyses indicate that the genosensor allows duplex formation with the DNA of pure sample of beef lysate. The genosensor was selective, identifying up to 1 % (w/w) of pork in beef samples, showing good reproducibility and stability within six weeks of storage, and can be reused four times, being a great tool for the evaluation of beef purity, with application in the meat production and marketing chain. [ABSTRACT FROM AUTHOR]

Pentaphenylantimony reacts on heating with 3-hydroxybenzoic acid in dioxane with the participation of carboxyl and hydroxyl groups to form tetraphenylantimony 3-tetraphenylstiboxybenzoate. Benzene-1,2,4,5-tetracarboxylic acid in the reaction with pentaphenylantimony acts as a polyfunctional compound and forms a tetranuclear complex – tetrakis(tetraphenylantimony) benzene-1,2,4,5-tetracarboxylate. Structural features of the synthesized compounds were determined by the X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

A characteristic feature of phytopathogenic Xanthomonas bacteria is the production of yellow membrane-bound pigments called xanthomonadins. Previous studies showed that 3-hydroxybenzoic 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 wildtype 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. [ABSTRACT FROM AUTHOR]

It has been established that pentaphenylantimony reacts with glutaric and 1,4-cyclohexanedicarboxylic acids to form bis(tetraphenylantimony) glutarate (I) and bis(tetraphenylantimony) 1,4-cycloxexanedicarboxylate (II, benzene solvate). According to X-ray diffraction data, the antimony atoms in molecules Ia and Ib have different coordination, one of which is distorted trigonal bipyramidal (CSbO axial angle, 178.67(9)° (179.63(9)°)); sum of СSbC equatorial angles, 358.02(11)° (357.13(11)°); Sb–O distance, 2.204(2) Å (2.215(2) Å)) and the other is distorted octahedral (CSbO angles, 149.49(9)°, 163.48(9)° (145.15(9)°, 169.18(9)°); CSbC angles, 157.58(11)° (157.70(11)°); Sb–O distances, 2.289(2), 2.413(2) Å (2.272(2), 2.417(2) Å)). In a centrosymmetric molecule of complex II, the antimony atoms have a distorted trigonal bipyramidal coordination (axial angle, 174.25(17)°; sum of equatorial angles, 356.7(2)°; Sb–O distance, 2.245(1) Å). The product of the reaction between pentaphenylantimony and 3-hydroxybenzoic acid (2 : 1 mol/mol) is the toluene solvate of the adduct of tetraphenylantimony 3-hydroxybenzoate and tetraphenylantimony 3-tetraphenylstiboxybenzoate (III) (toluene, 100°C) or the dioxane solvate of tetraphenylantimony 3-hydroxybenzoate (IV) (dioxane, 20°C). The antimony atoms in molecules of complexes III and IV have a trigonal bipyramidal coordination distorted to a different extent. [ABSTRACT FROM AUTHOR]

Converting renewable feedstocks to aromatic compounds using engineered microbes offers a robust approach for sustainable, environment‐friendly, and cost‐effective production of these value‐added products without the reliance on petroleum. In this study, rationally designed E. coli–E. coli co‐culture systems were established for converting glycerol to 3‐hydroxybenzoic acid (3HB). Specifically, the 3HB pathway was modularized and accommodated by two metabolically engineered E. coli strains. The co‐culture biosynthesis was optimized by using different cultivation temperatures, varying the inoculum ratio between the co‐culture strains, recruitment of a key pathway intermediate transporter, strengthening the critical pathway enzyme expression, and adjusting the timing for inducing pathway gene expression. Compared with the E. coli mono‐culture, the optimized co‐culture showed 5.3‐fold improvement for 3HB biosynthesis. This study demonstrated the applicability of modular co‐culture engineering for addressing the challenges of aromatic compound biosynthesis. [ABSTRACT FROM AUTHOR]

The reaction of 3-hydroxybenzoic (m-hydroxybenzoic) acid (MHBA), triethanolamine (TEA) and Ni(NO3)2 in aqueous solution led to formation of the hydrated title salt, [Ni(C6H15NO3)2](C7H5O3)·4H2O. In the complex cation, the Ni2+ ion is located on an inversion centre. Two symmetry-related TEA ligands occupy all coordination sites in an N,O,O′-tridentate coordination, leading to a slightly distorted NiN2O4 octahedron. Two ethanol groups of each TEA ligand form two five-membered chelate rings around Ni2+, while the third ethanol group does not coordinate to the metal atom. Two MHBA− anions in the benzoate form are situated in the outer coordination sphere for charge compensation. An intricate network of hydrogen bonds between the free and coordinating hydroxy groups of the TEA ligands, the O atoms of the MHBA− anions and the water molecules leads to the formation of a two-dimensional structure extending parallel to (010).

Copyright of Karaelmas Science & Engineering Journal / Karaelmas Fen ve Mühendislik Dergisi is the property of Karaelmas Science & Engineering Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report the synthesis and study of the mesomorphic behaviour for a series of bent-core materials based on 2-substituted 3-hydroxybenzoic acid as a central unit. Properties of the studied compounds are tuned by lateral substitution (F, Cl, CH3, NO2and CN) in the position 2 of 3-hydroxybenzoic 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. [ABSTRACT FROM PUBLISHER]

Vibrational modes of pyrazinamide (PZA), 3-hydroxybenzoic acid (3-hBA), and their cocrystal were characterized using terahertz time-domain (THz-TDS) and Raman vibrational spectroscopic techniques. In experimental THz spectra, the cocrystal has characteristic absorption bands at around 0.81, 1.47, and 1.61 THz, respectively, meanwhile the raw materials are absolutely different in this region. Raman spectra also show similar results about differences between the cocrystal and corresponding starting parent materials. Density functional theory (DFT) was used to simulate both optimized structures and vibrational modes of the cocrystal formed between PZA and 3-hBA. The vibrational modes of such cocrystal are assigned through comparing the simulation DFT frequency results with experimental vibrational spectra. The calculation of the theoretical THz spectrum shows that the hydrogen bonding effect established between H11⁻N12⁻H13 and the carboxyl group -COOH makes contributions to the formation of absorption peaks in 0.49, 0.62, 0.83, and 1.61 THz, which agrees pretty well with experimental results. The theoretical Raman result also matches well with experimental observations. The results provide a fundamental benchmark for the study of pharmaceutical cocrystal formation and also inter-molecular hydrogen bonding interactions between active pharmaceutical ingredients and various cocrystal coformers based on Raman and terahertz vibrational spectroscopic techniques combined with theoretical simulations.

Four new metal-organic supramolecular networks, namely, [Zn(Hpdc)(HO)]·2HO·bbi ( 1), {[Cd(Hpdc)]·2HO·Hbbi} ( 2), [Zn(BA)(bbi)] ( 3), and {[Cd(BA)(bbi)]·HO} ( 4) (Hpdc = 3,5-pyrazoledicarboxylic acid, HBA = 3-hydroxybenzoic acid and bbi = 1,1′-(1,4-butanediyl)bis(imidazole)) have been synthesized under hydrothermal conditions and characterized by IR spectra, elemental analyses, and single-crystal X-ray diffraction analyses. Compound 1 possesses zero-dimensional (0D) structure, which is finally extended into a two-dimensional (2D) supramolecular network via O-H···O and C-H···O hydrogen bonds. Complex 2 displays a 2D network structure built from Cd atoms interconnected by Hpdc ligands. The adjacent networks are further assembled into three-dimensional (3D) supramolecular structure through O-H···O hydrogen bonds. Compounds 3 and 4 show similar one-dimensional (1D) chains, in which four-coordinated Zn(II) atoms and six-coordinated Cd(II) atoms are bridged by bbi ligands. Through O-H···O and C-H···O hydrogen bonding interactions, the 1D chains are further packed into 2D and 3D supramolecular frameworks for 3 and 4, respectively. Obviously, the structural differences among compelxes 1- 4 are attributed to the different central metal atoms and organic ligands. In addition, compounds 1- 4 exhibit blue fluorescent emission in the solid state at room temperature. [ABSTRACT FROM AUTHOR]

The synthesis and mesomorphic properties of new series of bent-shaped liquid crystals are presented. The properties of the materials were tuned by the character of the lateral substituent in position 4 of the central aromatic ring and length of terminal alkyl chains. Further modification of physical properties was achieved by the introduction of an additional ester unit in the terminal alkyl chain. The physical properties of the studied materials were determined by differential scanning calorimetry, polarising optical microscopy and for selected compounds by x-ray diffraction. The influence of structural changes as well as the orientation of ester linkages (in comparison with previously described materials) is discussed. The addition of the fifth ester unit into the structure of the studied compounds leads to significant changes in their mesomorphic behaviour. [ABSTRACT FROM PUBLISHER]

Hereby, we present synthesis and mesomorphic properties of bent-shaped liquid crystals with 3-hydroxybenzoic 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 3-hydroxybenzoic 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 3-hydroxybenzoic acid) exerts only slight changes in physical properties of these structurally related materials. [ABSTRACT FROM AUTHOR]

Abstract: The excited-state proton transfer of 3-hydroxybenzoic acid and 4-hydroxybenzoic acid was studied by time-resolved laser-induced fluorescence spectroscopy with ultra-short laser pulses. The excited-state reactions were identified in aqueous media as a function of the pH value. Apart from the well-known inversion of the ordinary dissociation properties of these compounds, new species were found which exist only in the excited-state resulting from a temporal and reversible annihilation of the aromatic bond system. These species and their reaction mechanisms were detected by their absorption and fluorescence spectra. [Copyright &y& Elsevier]

Abstract: Solution and solid-state properties of m-hydroxybenzoic acid have been investigated. Two polymorphs were found where the monoclinic modification exhibits a higher stability than the orthorhombic form. The solubility of the monoclinic polymorph was determined between 10 and 50°C in methanol, acetonitrile, acetic acid, acetone, water and ethyl acetate. The solubility of the orthorhombic polymorph was determined between 10 and 50°C in acetonitrile, acetic acid, acetone and ethyl acetate. A thermodynamic analysis revealed a marked correlation between the molar solubility and the van’t Hoff enthalpy of solution at constant temperature. In addition, in each solvent increased temperature resulted in increased van’t Hoff enthalpy of solution. It is shown that the solubility data can be used to estimate melting properties for both polymorphs. The solubility ratio of the two forms and the DSC thermogram of the orthorhombic form strongly suggest that the system is monotropic. However, according to the polymorph rules of Burger and Ramberger, the estimated higher melting enthalpy and lower melting temperature of the orthorhombic form points towards an enantiotropic system. Hence, this system appears to be an exception to the Burger and Ramberger melting enthalpy rule, and the probable reason for this is found in the difference in the heat capacity of the two solid forms. [Copyright &y& Elsevier]

3-Hydroxybenzoic acid (3-HBA) was studied for possible use as a AISI 316L stainless steel (SS) corrosion inhibitor in an environmental-friendly aqueous pickling solution of 75 g l-1 sulphuric acid (H2SO4), 25 g l-1 hydrofluoric acid (HF) and 30 g l-1 hydrogen peroxide (H2O2). 3-HBA was tested in concentrations from 5 × 10-5 to 5 × 10-1Mat 298 and 313 K temperature. Inhibition efficiency increased with the 3-HBA concentration. The inhibitor mechanism is discussed in terms of the properties of the isotherm equations of Frumkin, Hill-de Boer and Kastening-Holleck mainly. The shape, the trend of the slopes along the curve and the existence of inflection points, were analysed as the characteristics that differentiate one adsorption equation from another. The best fit was obtained using the Frumkin isotherm model. The projected molecular area of 3-HBA was calculated as a structural parameter to elucidate its optimal inhibition mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new DNA sensor for Alicyclobacillus acidoterrestris detection was developed. • RGO/poly(3-hydroxybenzoic acid) nanocomposite was developed as platform. • Hoechst 33,258 was effectively used in the detection of DNA hybridization. • There was no need for DNA purification or amplification. • Orange juice has been shown not to interfere with detection. Alicyclobacillus acidoterrestris is an acidophilic and thermophilic bacterium present in the soil, often associated with the spoilage of acidic juices, such as orange juice. Their spores resist pasteurization and, when reactivated, modify the organoleptic properties of the juice, making it unsuitable for consumption, due mainly to production of guaiacol. Biosensors are detection devices that respond quickly and are easy to handle, with great potential for use in the juice production chain. In this context, this work reports an electrochemical genosensor for detection of A. acidoterrestris, based on a graphite electrode modified with electrochemically reduced graphene oxide, a polymer derived from 3-hydroxybenzoic acid and a specific DNA probe sequence complementary with the genomic DNA of A. acidoterrestris. Detection of the target was performed by monitoring the oxidation peak of the Hoechst 33258, a common DNA stainer. The genosensor detection limit was 12 ng mL−1 and it kept 77% of response after ten weeks, and a test showed that orange juice does not interfere with bacteria lysate detection. This biosensor is the first platform for electrochemical detection of the genomic DNA of A. acidoterrestris in the literature, and the first to use Hoechst 33258 as indicator with whole genomic DNA molecules. [ABSTRACT FROM AUTHOR]

Vibrational modes of pyrazinamide (PZA), 3-hydroxybenzoic acid (3-hBA), and their cocrystal were characterized using terahertz time-domain (THz-TDS) and Raman vibrational spectroscopic techniques. In experimental THz spectra, the cocrystal has characteristic absorption bands at around 0.81, 1.47, and 1.61 THz, respectively, meanwhile the raw materials are absolutely different in this region. Raman spectra also show similar results about differences between the cocrystal and corresponding starting parent materials. Density functional theory (DFT) was used to simulate both optimized structures and vibrational modes of the cocrystal formed between PZA and 3-hBA. The vibrational modes of such cocrystal are assigned through comparing the simulation DFT frequency results with experimental vibrational spectra. The calculation of the theoretical THz spectrum shows that the hydrogen bonding effect established between H11–N12–H13 and the carboxyl group -COOH makes contributions to the formation of absorption peaks in 0.49, 0.62, 0.83, and 1.61 THz, which agrees pretty well with experimental results. The theoretical Raman result also matches well with experimental observations. The results provide a fundamental benchmark for the study of pharmaceutical cocrystal formation and also inter-molecular hydrogen bonding interactions between active pharmaceutical ingredients and various cocrystal coformers based on Raman and terahertz vibrational spectroscopic techniques combined with theoretical simulations. [ABSTRACT FROM AUTHOR]

Chorismate-converting enzymes are involved in many biosynthetic pathways leading to natural products and can often be used as tools for the synthesis of chemical building blocks. Chorismatases such as FkbO from Streptomyces species catalyse the hydrolysis of chorismate yielding (dihydro)benzoic acid derivatives. In contrast to many other chorismate-converting enzymes, the structure and catalytic mechanism of a chorismatase had not been previously elucidated. Here we present the crystal structure of the chorismatase FkbO in complex with a competitive inhibitor at 1.08Å resolution. FkbO is a monomer in solution and exhibits pseudo-3-fold symmetry; the structure of the individual domains indicates a possible connection to the trimeric RidA/YjgF family and related enzymes. The co-crystallised inhibitor led to the identification of FkbO's active site in the cleft between the central and the C-terminal domains. A mechanism for FkbO is proposed based on both interactions between the inhibitor and the surrounding amino acids and an FkbO structure with chorismate modelled in the active site. We suggest that the methylene group of the chorismate enol ether takes up a proton from an active-site glutamic acid residue, thereby initiating chorismate hydrolysis. A similar chemistry has been described for isochorismatases, albeit implemented in an entirely different protein scaffold. This reaction model is supported by kinetic data from active-site variants of FkbO derived by site-directed mutagenesis., (© 2013.)