• Journal of the Korean Chemical Society
• /
• v.55 no.3
• /
• pp.392-399
• /
• 2011

Two conformations of benzoic acid derivatives ($NH_2$, OH, H, F, Cl, CN, NO, $NO_2$) have been investigated at MP2, DFT and HF level using the 6-311++G(d,p) basis set. It was found that the cis isomers are more stable. Hydrogen bonding formation of benzoic acids has been estimated from stabilization energies. The calculated hydrogen-bonding energies of dimers showed a cooperative interaction in the cyclic ones. It was found that an electron-releasing group (ERG) into the phenyl rings resulted in the formation of more stable hydrogen bonding. Red shift of O-H bond was found from -565.3 to -589.3 for dimers. The natural bond orbital (NBO) analysis was applied to characterize nature of the interaction.

• Journal of the Korean Chemical Society
• /
• v.35 no.3
• /
• pp.196-203
• /
• 1991

The $pK_a$ values of benzoic acid and meta, para-halogen substituted benzoic acids in MeOH-$H_2O$ mixtures (0∼80% of MeOH) have been determined at 25$^{\circ}$C using a conductometric method on the basis of the Fuoss-Kraus equation, and further verified using modified conductometric method of Gelb. The dependence of $pK_a$ on halogen substituents has been discussed in terms of substituent-constant (${\sigma}$), which is devided into electron-withdrawing inductive contribution (${\sigma}_1$) and electron-donating ${\pi}$-resonance one (${\sigma}_R$). The linear-dependence of ${\sigma}_1$'s on $D^{-1}$ with positive slope and that of ${\sigma}_R$'s on $D^{-1}$ with negative slope have been interpreted on the basis of field effect and through-space interaction of ${\pi}$-lone pair of halogen substituent and ionization center via ${\pi}$-system of benzene ring.

• Asian Journal of Turfgrass Science
• /
• v.12 no.3
• /
• pp.237-248
• /
• 1998

The soil pH favored by Korean wild plants is 5.33~7.20, while naturalized invader species prefer soils of pH 3.95~6.48. The germination rate of Zoysia japonica was inhibited sharply, up to 60%, in extracts of naturalized plants of concentrations over 50%. Erigeron canadensis extract most strongly inhibited germination, while the Korean wild species, Cassia mimosoides var. nomame increased germination rates in concentrations of 30% and 50%. The seedling growth of Zoysia japonica in extracts of Korean wild species and naturalized species did not show differences, but was inhibited strongly, up to 60%, in the extract of Cassia mimosoides var. nomame concentration of over 15%. Analysis of the extract from Cassia mimosoides var. nomame identified procatechuic acid, $\rho$-hydroquinone, $\rho$-coumaric acid and ferulic acid at 254nm; and vanillic acid, hydroquinone, benzoic acid and cinnamic acid were discovered at 284nm. The seed germination and seedling growth of Zoysia japonica were investigated under different concentrations of phenolic compounds. Ferulic acid and vanillic acid were associated with an increased germination rate, while $\rho$-coumaric acid appeared to inhibit seedling growth.

• YAKHAK HOEJI
• /
• v.32 no.3
• /
• pp.182-186
• /
• 1988

Binding of four cephalosporins(cefaclor, cefpiramide, ceftazidime, ceforanide) to bovine serum albumin was studied. Difference spectrophotometry was employed to evaluate the nature and the degree of association of cephalosporin-albumin complex. 2-(4'-hydroxybenzen azo) benzoic acid was used as the uv spectrophotometric probe for measuring the binding of cephalosporins to bovine serum albumin. Competitive bindings between cephalosporins and probe were observed. For the binding of cephalosporins to bovine serum albumin, three binding sites were identified. The binding constants of cefaclor, ceforanide, ceftazidime and cefpiramide were $12.57\;{\times}\;10^{-2}M^{-1}$, $6.49\;{\times}\;10^{-2}M^{-1}$, $4.70\;{\times}\;10^{-2}M^{-1}$ and $6.20\;{\times}\;10^{-2}M^{-1}$ respectively.

• Journal of Environmental Science International
• /
• v.16 no.2
• /
• pp.143-149
• /
• 2007

The effect of precoating of silica with polyamine surfactants on the adsorption of five model compounds containing asphalt-like functionalities was studied. Hexadecyltrimethylammonium chloride (HDTMA) and 1-hexadecylamine were used for silica precoating. The model compounds representing five asphalt functionalities were benzoic acid, phenol, benzylbenzoate, benzophenone, and quinoline. All the adsorption isotherms conformed well to the Langmuir adsorption model. All the model compounds showed decreased adsorption with the HDTMA precoating. However, two acidic compounds, benzoic acid and phenol, showed enhanced adsorption on the silica precoated with 1-hexadecylamine. In aqueous solutions, the adsorption of the acidic compounds were in the following order: silica precoated with 1-hexadecylamine > silica precoated with HDTMA > uncoated silica.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.3
• /
• pp.543-545
• /
• 2007

4-Hydroxy-3-(3'-methyl-2'-butenyl)-benzoic acid (HMBA) was previously isolated from Curvularia sp. KF119 as a cell-cycle inhibitor. However, the present study used a novel and practical synthetic method to prepare a large quantity of HMBA. The synthetic HMBA was found to inhibit the cell-cycle progression of HeLa cells with a comparable potency to the natural fungal metabolite. The inhibition of the cell-cycle progression by the synthetic HMBA involved both the activation of $p21^{WAF1}$ and the inhibition of cyclin D1 expression in the cells. Consequently, this new synthetic procedure provides an easy and convenient way to produce or manipulate the original fungal metabolite.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.6
• /
• pp.1230-1238
• /
• 1999

To identify antimicrobial activities of soybean paste, studies have been carried out with laboratory manufactured soybean paste, traditional and improved type soybean paste purchased on the market. The soybean paste fermented with Aspergillus oryzae and Rhizopus tamari and commercial soybean paste were shown antimicrobial activities for Bacillus cereus, Escherichia coli, Listeria monocytogenes, Staphy lococcus aureus, Streptococcus faecalis, Escherichia coli O157:H7, Bacillus subtilis and Salmonella typhimurium. Non fermented soybean paste did not show antimicrobial activities against Bacillus cereus, Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Streptococcus faecalis. The extract of soybean paste extracted by 80% methanol showed the highest antimicrobial activities of in ethyl acetate fraction and followed butanol fraction, respectively. Antimicrobial activities of traditional and improved type soybean paste were shown against all tested microorganisms and clear zone length of traditional soybean paste was slightly larger than that of improved type. Components of antimicrobial fractions of soybean paste were guessed peptides, 4 hydroxy benzoic acid, benzoic acid by GC MS.

• Molecular & Cellular Toxicology
• /
• v.1 no.4
• /
• pp.262-267
• /
• 2005

Using genetic engineering, the Vitreoscilla (bacterial) hemoglobin gene (vgb) was integrated stably into the chromosomes of and Burkholderia cepacia. Similar to previous results, the wild type VHb improved growth for Burkholderia cepacia and degradation of benzoic acid under both normal and low aeration conditions. The stable expression of VHb enhanced these parameters. The results demonstrate the possibility that the positive effects provided by VHb may be augmented by protein engineering.

• Journal of the Korean Chemical Society
• /
• v.18 no.5
• /
• pp.358-362
• /
• 1974

The anion exchange separation of a number of benzoic acid and its derivatives has been studied in various concentrations of $NiCl_2-methanol$ solvent medium. The volume distribution coefficients with Amberlite CG-400, $Cl^-$form have been measured in these medium. Several synthetic mixtures of organic acids were separated quantitatively by elution with a suitable concentration of $NiCl_2-MeOH$ solution suggested by the distribution data. The concentration of organic acids were determined by UV spectrophotometry.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.6
• /
• pp.528-533
• /
• 1995

Metallic iridium and rhodium powders prepared from the reactions of [M(COD)(PhCN)2]ClO4 (M=Ir(1), Rh(2); COD=1,5-cyclooctadiene) with hydrogen at room temperature in methylene chloride show catalytic activities for hydrogenation of arenes at room temperature under atmospheric pressure of hydrogen. Most substituents (CH3, COOH, NO2, CH2OH, CHO, OPh, OCH3, C=C, halogens and CH2Cl) on aromatic ring suppress the rate of the hydrogenation of the aromatic ring while the aromatic ring hydrogenation of phenol and 1,4-dihydroxobenzene is faster than that of benzene over these metallic powders. Hydrogenation of benzoic acid occurs only at the aromatic ring leaving the COOH group intact over iridium metal powders while benzoic acid is not hydrogenated at all over rhodium metal powders. Carbonyl, nitro, acetylenic and olefinic groups on an aromatic ring are hydrogenated prior to the aromatic ring hydrogenation. Hydrogenolysis of OH groups of phenol, benzyl alcohol and 1,4-dihydroxobenzene, and hydrodehalogenation of halobenzenes, benzyl halides and cinnamyl chloride also occur along with the hydrogenation of aromatic ring.