• KSBB Journal
• /
• 제15권6호
• /
• pp.541-547
• /
• 2000

Simulated moving bed (SMB) chromatography has been investigated in order to separate chiral compounds for pharmaceutical use. SMB utilizes the principle of true moving bed (TMB) chromatography, and has the advantages of low solvent usage, flexible configuration of columns and hardwares, and high productivity of the chiral compounds over the TMB. Large scale separation of xylene isomers and saccharides has been conducted since 1960s. However, the application of SMB in the fine chemical industries is still in the infant stage. The study of SMB for the chiral compounds production was initiated in the mid 1990s and further researches are actively undergoing. This review summarizes the principle of SMB as well as the chemistry of chiral stationary phase and chiral compounds.

• Bulletin of the Korean Chemical Society
• /
• 제16권6호
• /
• pp.489-492
• /
• 1995

A new synthetic route to chiral liquid crystal dopant, 4-[2-(7S-methylnonanyl)oxy-5-pyrimidinyl]phenyl(2S,3S)-2-chloro-3-methylpentanoate (1), starting from 4-nitrophenylacetic acid is described. The key intermediate methylthiopyrimidine compound (8) has been synthesized from 4-nitrophenylacetic acid by Vilsmyer-Haack reaction followed by the formation of pyrimidine ring, and then converted to chiral ester (1) by the replacement of nitro group by (2S,3S)-2-chloro-3-methylpentanoic acid 2 through the formation of diazonium salt.

• 공업화학
• /
• 제17권6호
• /
• pp.565-574
• /
• 2006

광학순도가 높은 이성체의 응용은 최근 들어 크게 증가되고 있는 추세이다. 여러 가지 방법 중에서도 비대칭 촉매합성반응을 통하여 선택적으로 순수한 광학이성체를 합성하는 것이 가장 매력적인 방법이다. 특히 키랄화합물을 합성하는 비대칭촉매반응에 있어서는 가격이 비싼 촉매를 소량 사용하면서도 활성이나 광학선택성 및 촉매수명을 높이도록 하는 조건이 매우 중요하게 대두된다. 활성이 큰 키랄촉매를 고정화시키면 반응 후에 반응혼합물을 여과법으로 쉽게 제거할 수 있다는 등의 취급상 용이한 점을 제공한다. 키랄촉매반응에서 생성물의 광학선택성을 향상시키고 여러 번 촉매를 재사용할 수 있도록 하려는 다양한 방법이 연구되고 있다. 본 총설에서는 여러 종류의 광학선택적인 불균일촉매에 관한 연구의 현황과 제한점 등을 주로 다루었다.

• Bulletin of the Korean Chemical Society
• /
• 제30권12호
• /
• pp.2938-2942
• /
• 2009

New receptors 1-3 that bind stereoselectively amino alcohols and convert chirality of amino acidsvia imine bond formation were synthesized. The receptors have uryl (1), thiouryl (2) and guanidinium (3) groups all with additional phenylcarbonyl motifs, which are effective hydrogen bonding donors and play a key role in the stereoselective recognitions. The stereoselectivities were measured from the integration of $^1HNMR$ peaks. Compound 1 and 2 showed the stereoselectivities for the imine formation with amino alcohols ($K_R/K_S$) in the range of 2${\sim}$4, and compound 3 in the range of 4${\sim}$8. Chirality conversion efficienciesof 1-3 for amino acids, i.e. D/L ratio at equilibrium, are in the range of 1.5${\sim}$5.6, showing a little higher efficiency with 3. The additional phenylcarbonyl motifs in 1-3 were revealed not to contribute to significant enhancement of the selectivities.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.363.1-363.1
• /
• 2002

Costunolide. a sesquiterpene lactone is isolated from Magnolia Sieboldi. It is known to possess antitumour and anti-inflammatory activities. This compound is synthesized from Ihe easily available decalin dione using the ring cleavage approach to construct the ten-membered ring system. The two keys points in this work are the chiral inductionon the allyl alcohol moiety using Sharpless epoxidation reaction and opening of the eopxide with an organocuprate reagent which leads to a $\alpha$-exomethylene lactone. (omitted)

• KSBB Journal
• /
• 제19권4호
• /
• pp.263-268
• /
• 2004

최근 생체 내에서 다른 약리활성을 보이는 키랄물질의 고순도 제조에 관심이 증가되고 있다. 현재 널리 사용되고 있는 것은 키랄고정상을 이용한 기존 분리방법에 비해서, 제조 후 안정성과 환경적인 측면을 고려한 초임계유체를 이용한 분리방을 시도하였다. 본 연구에서는 키랄물질인 ibuprofen의 최적의 분리 조건을 구하기 위해서 온도와 압력, 첨가되는 IPA의 양에 따른 체류인자와 분리도의 영향을 고찰하였다. 온도가 감소하고 압력이 증가할수록 체류인자는 감소하였다. IPA의 양에 따라 더 큰 영향을 받아서 IPA의 양이 많을수록 분리도는 감소하는 경향을 보였다. 실험으로부터 정한 최적의 분리조건은 130 bar, 311.15 K, 4% IPA (vol.)일 때이었다. 동일한 주입량에서 액체 크로마토그래피에서는 비선형의 용출곡선을 보였지만, 초임계유체 크로마토그래피에서는 선형의 용출곡선을 얻었다.

• 한국자기공명학회논문지
• /
• 제22권4호
• /
• pp.115-118
• /
• 2018

Dipyrromethane 2 functionalized with 3-chloropropyl group on the meso carbon undergoes an unusual intramolecular electrophilic aromatic substitution reaction in the presence of $NaN_3$ instead of a simple nucleophilic substitution reaction. As a result, a new chiral dipyrromethane 1 was synthesized. In this reaction, the ${\beta}$-carbon of the pyrrole ring functions as a nucleophile while the carbon next to the chlorine atom acts as an electrophile. Interestingly, this reaction progresses even in the absence of an acid catalyst. Compound 1 was fully characterized by $^1H-^1H$ and $^1H-^{13}C$ COSY NMR spectroscopic analyses and the high resolution EI mass spectrometry.

• 한국결정학회지
• /
• 제11권2호
• /
• pp.89-94
• /
• 2000

A crystallographic unit cell can be transformed into another one by a 3×3 transformantion matrix. If the determinant of the transformation matrix has a negative value, the newly transformed unit cell becomes a left-handed cell. The best way of transforming the left-handed cell to the right-handed one is to multiply each element of the transformation matrix by-1, and its corresponding transformation matrix must be applied tot he atomic coordinates of a noncentrosymmetric crystal so as to maintain the absolute configuration unchanged. The behaviour of absolute configuration caused by transforming the crystallographic unit cell was examined theoretically and experimentally on the compound (S)-(+)-4-phenyl-1-[4-aminobenzoyl) indoline-5-sulfonyl]-4,5-dihydro-2-imidazolone hydrochloride.

• Bulletin of the Korean Chemical Society
• /
• 제34권5호
• /
• pp.1371-1377
• /
• 2013

A new synthetic route to N-Cbz-cis-(3R,4R)-3-methylamino-4-methylpiperidine, key intermediate for CP-690,550, was disclosed with L-malic acid as the chiral pool starting material. The title compound was obtained in 16 steps with a total yield of 26% and more than 98% ee.

• Journal of Microbiology and Biotechnology
• /
• 제23권10호
• /
• pp.1395-1402
• /
• 2013

Reductases convert some achiral ketone compounds into chiral alcohols, which are important materials for the synthesis of chiral drugs. The Saccharomyces cerevisiae reductase YOR120W converts ethyl-4-chloro-3-oxobutanoate (ECOB) enantioselectively into (R)-ethyl-4-chloro-3-hydroxybutanoate ((R)-ECHB), an intermediate of a pharmaceutical. As YOR120W requires NADPH as a cofactor for the reduction reaction, a cofactor recycling system using Bacillus subtilis glucose dehydrogenase was employed. Using this coupling reaction system, 100 mM ECOB was converted to (R)-ECHB. A homology modeling and site-directed mutagenesis experiment were performed to determine the NADPH-binding site of YOR120W. Four residues (Q29, K264, N267, and R270) were suggested by homology and docking modeling to interact directly with 2'-phosphate of NADPH. Among them, two positively charged residues (K264 and R270) were experimentally demonstrated to be necessary for NADPH 2'-phosphate binding. A mutant enzyme (Q29E) showed an enhanced enantiomeric excess value compared with that of the wild-type enzyme.