• 생명과학회지
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• 제14권1호
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• pp.91-97
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• 2004

앞선 연구의 구조적 특성을 근거로 하여, 한 분자내에 MES 유발경련에 작용하는 cyclicimide의 구조를 포함하면, 그들의 구조가 경련 유발 수용체들에 상호 보완적으로 작용, MES및 PTZ유발 경련에 모두 작용할 수 있는 적용 범위가 넓은 항경련성 화합물이 될 수 있을 것으로 생각하여 N-acyl-$\alpha$-aminosuccinimide 1과 N-acyl-$\alpha$-aminoglutar- imide 2 유도체를 합성하였다. 먼저 (R)-2-benzyloxy carbonylamino-succinic acid 3을 출발 물질로 하여 N-acyl-a-aminosuccinimide 1 유도체인 (R)-Benzoic acid 4-benzyloxycarbonyl-amino-2-oxo-pyrrolidin-l-yl ester 6a, (R)4-nitro-benzoic acid 4-benzyloxycarbon-ylamino-2-oxo-pyrrolidin-1-yl ester 6b, (R)-4-nitro-benzoic acid 4-benzyloxycarbonylamino-2-oxo-pyrrolidin-1-yl ester 6c, 그리고 (R)-propionic acid 4-benzyloxycarbonylamino-2-oxo-pyrrolidin-1-yl ester 64를 합성하였다 또한 (R)-3-car-bobenzyloxy-aminoglutarrnic acid 7를 출발물질로 하여 N-acyl-$\alpha$-aminoglutarimide 2유도체인 (R)-(3-Benzyloxycarbonyl-amino-2,6-dioxo-piperidin-1-yloxy)-acetic acid methyl ester 10a, (R)-(3-benzyloxyarbonylamino-2,6-dioxo-piperidin-1-yloxy)-acetic acid ethyl ester l0b, 그리고 (R)-2-(3-benzylox-ycarbonylanino-2,6-dioxo-piperidin-1-yloxy)-propionic acid methyl ester l0c를 합성하였다. 합성된 화합물 6a, 6b, 6c, 6d, 10a, lOb, l0c에 대한 활성평가는 각 단계별 MES test와 PTZ test의 항경련 활성 시험 방법을 가지고 실험할 예정이다.

• KSBB Journal
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• 제27권3호
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• pp.167-171
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• 2012

A convenient liquid chromatographic enantiomer separation of several ${\alpha}$-amino acid esters as benzophenone Schiff base derivatives on covalently immobilized chiral stationary phases (CSPs) derived from polysaccharide derivatives was developed. The benzophenone imine derivatives of ${\alpha}$-amino acid esters were readily prepared by stirring benzophenone imine and the ${\alpha}$-amino acid ester hydrochloride salts in 2-propanol. The chromatographic conditions used on all CSPs were 0.5% or 5% 2-propanol/hexane (V/V) as the mobile phases at 1 mL/min of flow rate and UV 254 nm detection. The performance of Chiralpak IC among all CSPs was superior to that of the other CSPs for resolution of benzophenone imine derivatives of ${\alpha}$-amino acid esters. It is expected that the developed analytical method will be useful for enantiomer resolution of other ${\alpha}$-amino acid esters as benzophenone Schiff base derivatives.

• Bulletin of the Korean Chemical Society
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• 제26권6호
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• pp.989-992
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• 2005

Dynamic kinetic resolution of $\alpha$-bromo carboxylic acid derivatives in nucleophilic substitution with chiral $\alpha$-amino ester nucleophiles in the presence of TBAI and DIEA has been investigated for stereoselective syntheses of 1,1'-iminodicarboxylic acid derivatives. Nucleophilic substitutions with various chiral $\alpha$-amino esters gave iminodiacetates 2-8 with stereoselectivities up to 87 : 13 dr. Also, the reactions of N-($\alpha$-bromo-$\alpha$-phenylacetyl)-L-alanine methyl ester with L-alanine, D-alanine and glycine methyl ester nucleophiles afforded N-carboxyalkyl dipeptide analogues 10-12 up to 90 : 10 dr.

• KSBB Journal
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• 제28권6호
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• pp.423-427
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• 2013

A new convenient derivatization method of ${\alpha}$-amino acid esters as nitrobenzoxadiazole (NBD) derivatives for chiral resolution was introduced and the enantiomer separation of ${\alpha}$-amino acid esters as NBD derivatives was performed by normal HPLC using chiral columns based on polysaccharide derivatives. The NBD derivatives were readily prepared by stirring NBD-Cl and ${\alpha}$-amino acid methyl ester HCl with $NaHCO_3$ in ethanol. The performance of Chiralpak IA was superior to the other chiral stationary phases for enantiomer resolution of NBD derivatives of several ${\alpha}$-amino acid methyl esters. Owing to fluorescence detection as well as strong UV absorption, it is expected that the convenient analytical method developed in this study will be very useful for enantiomer separation of ${\alpha}$-amino acid esters as NBD derivatives on polysaccharide-derived chiral columns.

• KSBB Journal
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• 제26권2호
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• pp.139-142
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• 2011

The chromatographic enantiomer separation of 9-anthraldimine derivatives of ${\alpha}$-amino acid methyl and ethyl esters on four polysaccharide based chiral columns was performed. The 9-anthraldehyde Schiff base derivatives of ${\alpha}$- amino acid esters were readily synthesized by stirring the ${\alpha}$- amino acid ester hydrochloride salts with 9-anthraldehyde in the presence of 1,8-diazabicyclo [5.4.0]undec-7-ene as a base and anhydrous $MgSO_4$. Chiralcel OD or Chiralcel OD-H showed the greatest enantiomer resolution of 9-anthraldimine derivatives of ${\alpha}$-amino acid methyl and ethyl esters. The L-enantiomers of all the analytes were preferentially retained on Chiralcel OD or Chiralcel OD-H. This analytical method was applied in the determination of optical purities of several commercially available D- or L-${\alpha}$-amino acid methyl esters.

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.329-332
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• 2001

It has been known that, in enzymatic synthesis of cephalexin, the conversion yield was reduced by high loading of ampicillin acylase. In order to elucidate this phenomena, pH-controlled synthesis of cephalexin was examined using a purified Acetobacter turbidans acylase. When the pH of the reaction mixture was maintained at $6.20{\pm}0.04$, the reduction of the maximal conversion rate was not observed even with high enzyme loading. The kinetic parameters also suggest that pH drop during the enzymatic synthesis of cephalexin was mainly attributed to the rapid hydrolysis of D-${\alpha}$-phenylglycine methyl ester to D-${\alpha}$-phenylglycine, rather than the disappearance of 7-amino-3-deacetoxycephalosporanic acid for cephalexin synthesis. At higher molar ratio of two substrates, [D-${\alpha}$-phenylglycine methyl ester]/[7-amino-3-deacetoxycephalosporanic acid], the conversion rate was also elevated under pH-controlled enzymatic synthesis, which implies that the main reason for the pH drop is due to the production of D-${\alpha}$-phenylglycine methyl easter, the effect of a water-methanol cosolvent system on the ester, the effect of a water-methanol cosolvent system on the conversion profile was also examined. Even the though the conversion rate was increased in 10% methanol solution, a higher than 16% methanol in the reaction mixture caused an inactivation of enzyme.

• 약학회지
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• 제41권5호
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• pp.575-581
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• 1997

The 6,7-dichlorquinoline-5,8-dione was reacted with ${alpha}$-cyanoacetic acid ethyl ester in ammonia solution to yield 6-(${alpha}$-cyano-${alpha}$-ethoxycarbonyhnethyl)-7-chloroquinoline- 5,8-dione (compound I). When this compound was reacted with some alkyl amines (methylamine, ethylamine, isopropylamine, etc) 2-amino-3-ethoxycarbonyl-N-alkyl-pyridino[2,3-f]indole-4,9-diones (compounds II a-e) were obtained.

• KSBB Journal
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• 제27권4호
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• pp.232-236
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• 2012

Comparative liquid chromatographic enantiomer separation of ${\alpha}$-amino acids, their esters and primary amino compounds was performed using two chiral stationary phases (CSPs) prepared by covalently bonding (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18-C-6-TA) of the same chiral selector. In general, the separation factors and resolution factors for these analytes on CSP 1 were greater than on CSP 2, while these capacity factors on CSP 2 were quite greater than on CSP 1. Except for leucine methyl ester and phenylalanine methyl ester, the elution orders of all analytes including ${\alpha}$-amino ${\alpha}$-alkyl acids and phenylglycine alkyl esters on CSP 1 are identical to those on CSP 2. This study showed that different connecting structures for these two CSPs might influence their ability to resolve the analytes depending on their structures related to the chiral recognition mechanism.

• 대한화학회지
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• 제8권4호
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• pp.135-141
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• 1964

아밀아이오다이드를 디메칠홀움아마이드 存在下에서 弗化加里와 低溫反應시켜 본 結果 弗化物과 데칸을 生成하였음. ${\alpha}$, ${\beta}$-디크로로-${\beta}$-페닐-푸로피온酸과 같은 多鹽素化物은 ${\alpha}$-크로로스타이렌, 弗化스타이렌 及 弗化酸을 生成하였음. 이 酸의 에칠에스텔은 弗化物을 生成하지 않고 各種 쌍合物의 混合物을 얻었음. 디부롬스타이렌은 부롬스타이렌과 弗化物을 生成하고 沃度를 含有한 有機酸, 메-타요드벤젠익酸은 有機酸의 鹽과 微量의 쌍合物을 生成하였음. 메타요드토류엔 及 1-아미노-4-요-드-2-메칠벤젠과 같은 沃化物은 弗化物은 弗化加里에 對하여 反應을 나타내지 않었음. 本報에는 各 反應條件과 弗化反應, 脫炭酸反應 及 쌍合反應에 關하여 論義하였음.

• 대한화학회지
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• 제53권2호
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• pp.137-143
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• 2009

공유결합된 다당유도체에서 유도된 카이랄 칼럼인 Chiralpak IC을 사용하여 N-BOC $\alpha$-amino acid와 그들의 ethyl ester 유도체의 액체크로마토그래피 거울상 이성질체의 분리를 수행하였다. 다양 한 이동상에서 공유결합된 카이랄 칼럼인 Chiralpak IC에서 거울상 이성질체가 분리된 실험결과를 나 타내었으며, 광학분할의 선택성과 분리인자가 이동상에 따라 크게 영향을 받았다. 또한 동일한 이동 상에서 분석물질의 녹이는 용매에 따라 거울상 이성질체의 분리에 미치는 영향과 분석용 컬럼에서 거울상 이성질체의 분리의 여러 예를 나타내었다.