• KSBB Journal
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• v.18 no.1
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• pp.1-7
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• 2003

Screening of a strain was carried out to produce an enantioselective lipase toward the precursor of ltraconazole as azole-containg compounds, which are well known as antifungal drug agents. An Acinetobacter sp. SY-01 strain which can selectively hydrolyze the racemic substrates was isolated and the racemic substrate was resolved to the S-ester in 95.6% enantiomeric excess after 74.8% hydrolysis. The optimum temperature and pH for the conversion were $50^{\circ}C$, pH 7.0. However, the temperature and pH had no effect on the enantiomeric excess. Addition of solvents decreased the conversion and slightly increased the enantiomeric excess. However, the kind of solvents had no effect on enantiomeric excess. The substrate concentration decrease enantiomeric excess and this is confirmed by the products generated from hydrolysis, and also enantiomeric excess could be increased by the removal of reaction products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.874-880
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• 2006

The volatile compounds of Zingiber officinale Roscoe were extracted by simultaneous steam distillation and extraction (SDE) method and identified with gas chromatigraphy/mass spectrometer (GC/MS) analysis. Enantiomeric compositions of chiral compounds were determined by multidimensional gas chromatography/mass spectrometer (MDGC/MS). A total of 57 compounds were indentified and quantified, including zingiberene, ${\beta}-sesquiphellandrene$, ${\beta}-bisabolene$, $(E,E)-{\alpha}-farnesene$ and ${\alpha}-curcumene$. Among them, zingiberene (38.41%) was founds as the predominantly abundant component. ${\alpha}-Pinene$ and nerolidol in dried ginger were detected by high enantiomeric purity (>96%) for (S)-form, and ${\beta}-pinene$ was detected only (R)-form. The enantiomeric composition of ${\alpha}-terpineol$ revealed 72.0% for (R)-form, and linalool and 4-terpineol showed mixtures of both enantiomers. (S)-Enantiomer was the major enantiomer of limonene having enatiomeric excess of 17.2%. Hence the enantiomeric composition of these compounds can be used as parameter for authenticty control of Zingiber officinale.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.217-221
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• 2001

Pseudomonas sp. PA09 was isolated from farm soil and used for the optical resolution of D-pipecolic acid from DL-popecolic acid. The strain PA09 consumed L-pipecolic acid preferentially as the sole carbon and energy source, thus accumulating D-pipecolic acid in the culture broth. Optimization to improve the enantiomeric excess and yield was performed. The time course experiment showed that the strain OP09 consumed L-pipecolic acid almost to completion after 35h of cultivation, and the enantiomeric excess and the yield (% of residual D-pipecolic acid) were 99.8 and 96.0%, respectively.

• Microbiology and Biotechnology Letters
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• v.28 no.4
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• pp.223-227
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• 2000

A novel two-step acetone treatment method was developed to enhance the enantioselectivity of Candida rugosa lipase (CRL) toward the hydrolysis of racemic naproxen methyl ester. The acetone-teated CRL was considerably more enantioselective than the crude CRL, yielding an enantiomeric excess of 98~100%. The crude and acetone-treated CRLs were subjected to anion exchange chromatography, and their chromatography profiles were compared. In consequence, both chromatography profiles were found to be almost identical, resulting in two separate lipase peaks (lipase A and B). The lipase B, which is known to be less enantioselective, was treated with acetone using a two-step treatment method. The enantioselectivity of acetone-treated lipase B was dramatically increased, yielding an enantiomeric excess of 99%.

• Applied Chemistry for Engineering
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• v.5 no.1
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• pp.176-181
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• 1994

The hydrolysis of biochemical kinetic resolutions for 2-[1-(acetoxy-2, 2, 2-trifluoroethyl)]-5-trimethylsilylfuran(1) using kinds of Lifase(talpase, paratase, M1000L, SP398, SP435) was investigated. In the results SP435 of Novo Nordish comp any was confirmed to show the capacity of biochemical kinetic resolutions, and 2-(1-(2, 2, 2-trifluoro-1-hydroxyethyl)]-5-trimethylsilylfuran(2) to have the optical purity expressed as 92.4% enantiomeric excess(ee) was produced in this studies.

• Journal of the Korean Society of Industry Convergence
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• v.12 no.3
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• pp.143-147
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• 2009

The enantioselective reduction of representative prochiral alkyl-aryl ketones with a new chiral alkoxy-amine-aluminum derivatives from aluminum hydride and ${\alpha},{\alpha}$-diphenyl-${\beta}$-amino alcohols, such as (S)-(-)-2-amino-3-methyl-1,1-diphenylbutan-1-ol(AMDPB) and (S)-(-)-2-(diphenylhydroxy-methyl)pyrrolidine(DPHMP), in THF at $0^{\circ}C$ was studied. In the reduction of alkoxy-amine-aluminum derivatives, acetophenone, propiophenone, isopropiophenone, and butyrophenone are reduced to corresponding aromatic secoundary alcohols with 34~60 % enantiomeric excess of (S)-isomers. For such ketones, the optical induction was enhanced by increasing a size of alkyl groups.

• Journal of the Korean Chemical Society
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• v.59 no.6
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• pp.488-492
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• 2015

In this study, the effective preparation method of (S)-(+)-pranidipine, the active component of antihypertensive drug as a calcium channel blocker, was developed using optical resolution. The racemic monocarboxylic acid 5 obtained by the hydrolysis of (±)-pranidipine was mixed with optically active quinidine to form salts, and the insoluble diastereomeric salt was collected and successive treatment with base and acid furnished (R)-(-)-carboxylic acid 7. (S)-(+)-Pranidipine was prepared by esterification of this acid with cinnamyl alcohol, and the analysis by chiral HPLC showed 100% enantiomeric excess (ee). This process would be industrially very useful to prepare chiral (S)-(+)-pranidipine, since the use of strong base and anhydrous solvents, and ultra-low temperature condition were excluded in this process.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.18-24
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• 2009

The volatile compounds of dried sancho (Zanthoxylum schinifolium), an aromatic plant were extracted by simultaneous distillation and extraction (SDE) method and identified by gas chromatograph-mass spectrometry (GC-MS). Selected chiral constituents of sancho oil were characterized by enantiodifferentiation using multidimensional gas chromatograph (MDGC)-MS. A total of 57 compounds were identified and quantified, and the major compounds were identified estragole, nonanoic acid, octanoic acid, $\beta$-phellandrenene, and limonene. Among them, estragol (63.9%) was found as the predominantly abundant component of sancho. $\alpha$-pinene and nerolidol, and $\beta$-pinene and linalool were determined to be enantiomerically pure (100%) for their (S)-form and (R)-form, respectively. The enantiomeric composition of limonene in sancho revealed 83.9% purity for the (S)-enantiomer, whereas (E)- and (Z)-rose oxides showed mixtures of both enantiomers. The enantiomeric excess (%) for citronellal was 22.6% with the (R)-enantiomer as major enantiomer. The enantiomeric composition of these compounds can be used as parameter for authenticity control of sancho.

• Journal of the Korean Chemical Society
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• v.34 no.2
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• pp.159-164
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• 1990

Absolute configuration of optically active [Co(EDDS)]- (EDDS = ethylenediaminedisuccinate) complex was determined as Λ-form by octant rule and spectroscopic data, and the stereoselective ionic association of Λ-[Co(EDDS)]- and racemic-$[Co(en)^3]_{3+}$ occurs preferrentially between Λ$-[Co(EDDS)]-$ and Δ$-[Co(en)3]3+$. The stereoselective electron-transfer reaction between Λ-[Co(EDDS)]- and racemic-$[Co(en)_3]^{2+}$ has produced 14% e.e (e.e = enantiomeric excess) of Δ$[Co(en)_3]^{3+}$ through the stereoselective ion pairing.

• Polymer(Korea)
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• v.28 no.4
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• pp.352-359
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• 2004

Membrane technology was used for the optical resolution of the various racemic compounds such as tryptophan, tyrosine and phenylalanine, using enantioselective membranes prepared from sodium alginate (SA) and glutaraldehyde as a membrane material and crosslinking agent, respectively, The chemical structure of the membranes was characterized with FT-IR spectrophotometry and 3D molecular structure modeling study was done to figure out the optical resolution mechanism through the membrane. Effects of degree of crosslinking, feed concentration, operating pressure and different kinds of feed solution on the membrane performances were studied. As results, it was found that with increasing degree of crosslinking and membrane thickness, and decrease in the concentration of the feed solution and smaller size of solutes, the enantinselectivity of the membrane was improved. When the sodium alginate membranes with 80% of swelling index and 79${\mu}{\textrm}{m}$ of thickness were used, 77% of enantiomeric excess was obtained.