• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.241-241
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• 2006

Absolute configuration of carboxylic acids, including amino acids can be determined by circular dichroism (CD) exciton chirality method. This method employs cyclic oligopyrroles able to form stable complexes with carboxylic acids. Addition of carboxylic acids to the oligopyrroles induce CD spectrum at the macrocycle absorption region and in which the sign of the $1^{st}$ Cotton effect is determined solely by the absolute configuration of the carboxylic acid. The basicity of the pyrrole nitrogen can be controlled by macrocycle substitution thus yielding more sensitive chirality sensors.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.381-385
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• 1999

Taq DNA polymerase from Thermus aquaticus has been shown to be very useful in a polymerase chain reaction. Taq DNA polymerase has a domain at the amino terminus (residues 1 to 290) that has 5'-3' exonuclease activity and a domain at the C-terminus that catalyzes the polymerase reaction. Taq DNA polymerase is classified into the Pol I family, which is represented by E. coli DNA polymerase I. The alignment of amino acid sequences for the 5'-3' exonuclease domains of the Pol I family DNA polymerases shows ten highly conserved carboxylic amino acids. Crystallographic studies suggested that six of the carboxylic amino acids are clustered within a 7 $\AA$ radius by chelating three metal ions in the active site. Those six carboxylic residues are mutagenized to alanines in order to better understand their function. All six carboxylic residues, Asp l8, Glu1l7, Asp1l9, Asp120, Asp142, and Aspl44, are crucial for catalysis of 5'-3' exonuclease.

• Proceedings of the PSK Conference
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• 2005.11a
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• pp.190-191
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• 2005

• YAKHAK HOEJI
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• v.38 no.2
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• pp.197-201
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• 1994

A number of 7-[(3-methylthio or methylthiomethyl)pyrrolidiny]qui nolone-3-carboxylic acids were synthesized by condensation of 7-fluoro substituted quinolone-3-carboxylic acid with 3-methylthiopyrrolidine or 3-methylthiomet hylpyrrolidne. 3-Methylthiopyrrolidine or 3-methylthio-methylpyrrolidine which was prepared from N-benzyl-3-hydroxy pyrrolidine or 3-hydroxymethylpyrrolidine. The in vitro antimicrobial activity of them were tested against twenty species of Gram-positive or Gram-negative microorganisms. It showed remarkable antibacterial activity, particularly against Gram-positive microorganisms. Among those 1-cyclopropyl-6,8-difluoro-7-(3-methylthiomethy-lpyrrolidinyl)-1,4-d ihydro-4-oxo-3-quinolinecarboxylic acid(7d) and 1-cyclopropyl-6- fluoro-8-chloro-7-(3-methylthiomethyl pyrrolidinyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (7f) showed the most potent in vitro antibacterial activity.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2529-2530
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• 2011

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.207-212
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• 2004

In this study, we attempted to prepare compounds with heterocyclic replacements for metabolically unstable esters of benzopyranyl indole-2-carboxylic esters, which showed good in vitro and in vivo cardioprotective efficacies possibly through the opening of mitochondrial ATP-sensitive potassium channel ($K_{ATP}$). Initially, we tried to construct indolin-2-yl-heterocycles using unprotected indoline-2-carboxylic acid, but the cyclization was proceeded with oxidation of the indoline ring to the indole, which didn't react with benzopyranyl epoxide. Thus we introduced N-Boc group to deplete the electron density of the indoline ring. We successfully prepared various indolin-2-yl-heterocycles by the cyclization of the building blocks including carboxamide, ${\beta}$-hydroxy amide, hydrazide, nitrile starting from N-Boc-indoline-2-carboxylic acid.

• Journal of the Korean Magnetic Resonance Society
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• v.21 no.4
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• pp.135-138
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• 2017

Titanium phenoxide and titanium carboxylate derivatives were prepared by ligand exchange of titanium tetraisopropoxide with the corresponding phenol and carboxylic acids. The substitution reactions were analyzed by NMR focused in the liberation of isopropylalcohol. The chemical shift of secondary proton of isopropyl group shifted to upfield after liberation; from 4.47 ppm at titanium-bound to 4.1~4.3 ppm at free alcohol state in $CDCl_3$. The substitution reaction of titanium tetraisopropoxide with carboxylic acid was applied to form dye-Ti complex for dye-sensitized solar cell.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.6
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• pp.386-394
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• 2001

Carboxylic acids are examples of compounds with wide industrial applications and high potential, This article presents the principles of reactive extraction along with the character-istics of tertiary amine extractants, while is given on considering the effect of the amine class and chain length, As such a brief overview the current research on reactive extraction, including the recovery of citric acid, selective amine-based extraction , and extractive fermentation is given. When discussing extractive fermentation strategies for reducing solvent toxicity are also suggested based on specific examples. Finally, solvent regeneration and stripping of extracted acid explained.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.384-388
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• 1988

New methods of the reduction of carboxylic acid salts to aldehydes with 2 equiv of thexylbromoborane-dimethyl sulfide (ThxBHBr${\cdot}SMe_2$) or 9-borabicyclo[3.3.1]nonane (9-BBN) are described. Both these reagents provide the corresponding aldehydes from various as sodium and lithium salts of carboxylic acids in high yields both at room temperature. Such facile reductions are explained as the simple substitution for the bromo group of ThxBHBr by a carboxylate to form thexyl(acyloxty)borane followed by reduction with excess reagent and the formation of an ate complex followed by reduction with excess 9-BBN.

• Parasites, Hosts and Diseases
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• v.48 no.2
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• pp.127-132
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• 2010

Biomphalaria alexandrina snails play an indispensable role in transmission of schistosomiasis. Infection rates in field populations of snails are routinely determined by cercarial shedding neglecting prepatent snail infections, because of lack of a suitable method for diagnosis. The present study aimed at separation and quantification of oxalic, malic, acetic, pyruvic, and fumaric acids using ion-suppression reversed-phase high performance liquid chromatography (HPLC) to test the potentiality of these acids to be used as diagnostic and therapeutic biomarkers. The assay was done in both hemolymph and digestive gland-gonad complex (DGG) samples in a total of 300 B. alexandrina snails. All of the studied acids in both the hemolymph and tissue samples except for the fumaric acid in hemolymph appeared to be good diagnostic biomarkers as they provide not only a good discrimination between the infected snails from the control but also between the studied stages of infection from each other. The most sensitive discriminating acid was malic acid in hemolymph samples as it showed the highest F-ratio. Using the Z-score, malic acid was found to be a good potential therapeutic biomarker in the prepatency stage, oxalic acid and acetic acid in the stage of patency, and malic acid and acetic acid at 2 weeks after patency. Quantification of carboxylic acids, using HPLC strategy, was fast, easy, and accurate in prediction of infected and uninfected snails and possibly to detect the stage of infection. It seems also useful for detection of the most suitable acids to be used as drug targets.