• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1471-1473
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• 2004

An efficient dynamic kinetic resolution of racemic ${\beta}$-hydroxyalkylferrocene and 1,1'-bis( ${\beta}$-hydroxyalkyl)-ferrocene derivatives was achieved using lipase/ruthenium-catalyzed transesterification in the presence of an acyl donor. The racemic ${\beta}$-hydroxyalkylferrocene derivatives were successfully transformed to the corresponding chiral acetates of high optical purities in high yields.

• KSBB Journal
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• 제9권3호
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• pp.306-311
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• 1994

유기용매상에서 Bacillus licheniformis에서 생산되는 protease를 이용하여 라세믹 ${\alpha}$-methylbenzy lamine의 광학분함을 행하였다. 이 반응은 아설 제 공자로 활성 에스대르를 샤용하여 라서l믹 아민을 광 학선택적으로 아마드로 변환시킨다. 이 반응의 반응 속도와 광학선택성을 증가시켜주기 위해 효소를 완 충액에 녹여 pH를 맞춘 후에 동결건조시키거나, 동결건조시 염이나 lyoprotectants를 첨가시키는 방 법, 적당한 유기용매의 선정, 에스테르 구조의 디자 인 등의 방법을 사용하였다. 그 결과. 30배의 초기 반응속도의 증가 및 12배의 광학선택성이 증가하는 결과를 보였다.

• KSBB Journal
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• 제17권6호
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• pp.543-548
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• 2002

Candida rugosa lipase를 이용하여 효소 농도, 반응온도, 알콜 농도 및 종류 등의 반응조건에 따른 racemic ibuprofen 에스테르화 반응의 초기반응속도, 전환율 그리고 입체 선택성 을 조사하였다. 제조된 S-(+)-ibuprofen alkyl ester는 황산을 촉매로 하는 가수분해반응에 의해 순수한 S-(+)-ibuprofen으로 전환되었다. 에스테르화 반응에서는 반응온도 6$0^{\circ}C$에서 최대 활성을 보였으며, 그 이상의 온도에서는 효소의 활성 저하로 전환율과 enantiomeric excess값이 동시에 현격하게 감소하는 경향을 보였다. 알코올 농도가 증가할수록 알콜의 효소반응 저해제작용으로 인하여 초기반응속도가 감소하는 경향을 보였으며, 최종 전환율은 Ibuprofen와 Alcohol의 몰 비가 1/1에서 최고 값을 나타냈다. 알콜 종류에 따른 알코올 체인 길이가(C$_2$~C$_{10}$) 증가할수록 전환율은 증가하였는데, 특히 알코올 체인길이가 가장 큰 데칸올이 가장 높은 전환율을 보였다. 반응온도가 6$0^{\circ}C$ 이상의 높은 경우를 제외하고 에스테르화 반응 조건에 따라 입체 선택성 즉 enantiomeric excess의 큰 변화는 없었다. 화학적 가수분해 반응은 비교적 짧은 반응시간(3시간)내에 평형반응에 도달하였으며 알코올 체인 길이에 관계없이 거의 95% 이상의 높은 전환율 및 입체 선택성을 나타냈다. Lipase에 의한 ibuprofen 에스테르화 반응의 최적 조건과 화학적인 가수분해 반응을 통해서 racemic ibuprofen으로부터 높은 수율의 S-(+)-ibuprofen을 확보할 수 있었다.

• 한국응용과학기술학회지
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• 제7권1호
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• pp.107-114
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• 1990

Optical resolution of aminoalcohols had been achived efficiently by use of (R)-2,2'-dihydroxy-l,1'-binaphtholphosphoric acid as the resolving agent in various organic solvents. Racemic aminoalcohols were resolved very easily and high enantiomer yield (about 70% e,e) in THF. On the other hand, absolute configuration of resolved aminoalcohol was (R)-configuration but one of the Valinnol and Phhenylglycinol was anti-type because of sterichindrance.Optical resolution of aminoalcohols had been achived efficiently by use of (R)-2,2'-dihydroxy-1,1'-binaphtholphosphoric acid as the resolving agent in various organic solvents. Racemic aminoalcohols were resolved very easily and high enantiomer yield (about 70% e,e) in THF. On the other hand, absolute configuration of resolved aminoalcohol was (R)-configuration but one of the Valinnol and Phhenylglycinol was anti-type because of sterichindrance.

• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1269-1275
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• 2003

The quaternary carbon-containing alcohols (1-6) were resolved enantioselectively by various lipases such as PFL (Pseudomonas fluorescens lipase), LAK (Pseudomonas fluorescens lipase), CRL (Candida rugosa lipase) and PCL (Pseudomonas cepacia lipase). The enzymatic resolution of racemic alcohol $({\pm})-2$ gave the excellent enantioselectivity in favor of (S)-2d in 99% ee, while those of the racemic alcohols (1, 3, 4, 5 and 6) gave the resolved alcohols with moderate to good enantioselectivity. Also, their absolute configurations were determined by chemical transformation to the known compounds.

• Bulletin of the Korean Chemical Society
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• 제19권8호
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• pp.819-821
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• 1998

• Bulletin of the Korean Chemical Society
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• 제10권6호
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• pp.618-619
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• 1989

• Bulletin of the Korean Chemical Society
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• 제18권3호
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• pp.336-339
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• 1997

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.285.1-285.1
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• 2003

ChiroSil RCA(+) and SCA(-) HPLC chiral stationary phases (CSPs) developed by covalently bonding (+)- and (-)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18-C-6-T A) to silica gel were employed for enantioresolution of racemic amino compounds, respectively. Also, these 18-C-6-TA covalently bonded CSPs were compared to a commercially available Crownpak CR CSP prepared by coating chiral crown ether as a chiral selector on ODS column. (omitted)

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.167-179
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• 2005

Chiral epoxides are highly valuable intermediates, used for the synthesis of pharmaceutical drugs and agrochemicals. They have broad scope of market demand because of their applications. A major challenge in modern organic chemistry is to generate such compounds in high yields, with high stereo- and regio-selectivities. Epoxide hydrolases (EH) are promising biocatalysts for the preparation of chiral epoxides and vicinal diols. They exhibit high enantioselectivity for their substrates, and can be effectively used in the resolution of racemic epoxides through enantioselective hydrolysis. The selective hydrolysis of a racemic epoxide can produce both the corresponding diols and the unreacted epoxides with high enantiomeric excess (ee) value. The potential of microbial EH to produce chiral epoxides and vicinal diol has prompted researchers to explore their use in the synthesis of epoxides and diols with high ee values.