• 통합자연과학논문집
• /
• 제8권2호
• /
• pp.111-116
• /
• 2015

Liquid chromatographic enantiomer separation of ${\alpha}$-amino acid esters as nitrobenzoxadiazole (NBD) derivatives was performed using several chiral stationary phases (CSPs) based on polysaccharide derivatives under fluorescence detection. For enantiomer separation by normal HPLC, the non-aqueous derivatization method of ${\alpha}$-amino acid esters for NBD analytes was introduced. Among the six CSPs used in this study, the performance of Chiralpak IA was superior for enantiomer resolution of NBD derivatives of several ${\alpha}$-amino acid methyl esters. Also the convenient analytical method using polysaccharide-derived CSPs developed in this study was applied to determine the optical purity of ${\alpha}$-amino acids esters. It was investigated that the enantiomeric impurity levels of 0.02-1.73% were found after determination of enantiomeric purities of several commercially available L-amino acid methyl esters. It is expected to be quite useful for enantiomer separation of other ${\alpha}$-amino acid esters as NBD derivatives by normal HPLC.

• KSBB Journal
• /
• 제28권6호
• /
• pp.423-427
• /
• 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
• /
• 제27권3호
• /
• pp.167-171
• /
• 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.

• 한국응용과학기술학회지
• /
• 제28권4호
• /
• pp.438-448
• /
• 2011

Chitosan is widely used in cosmetics and medical fields. Special emphasis has been put on the chemical modification of chitosan to explore its full potential. We have described the synthesis and biological activity of novel peptide amino acid derivatives. The polyamino acid derivatives were synthesized by introducing alkylamine functional group on chitosan at C-6. The poor aqueous solubility of chitosan derivatives hinder both pharmacological studies and pharmaceutical development. To make amino acid coupled chitosan derivatives with improved biological effect and solubility, some attempts have been taken to consist of amino peptide group like aspartic acid and phenylalanine-aspartic acid derivatives onto chitosan C-6. The resultingly substituted chitosan was characterized by solubility in various solvents. We measured chitosan derivatives with $^1H$-NMR and $^{13}C$-NMR. Also, We were investigated on the physical properties and biological activities of these products.

• Archives of Pharmacal Research
• /
• 제15권2호
• /
• pp.130-133
• /
• 1992

A series of copper complexes of some amino acid derivatives of 6-methoxy 3-methyl-coumarilic acid were prepared. The infrared, visible spectra and magnetic susceptibility of these compounds were reported. All copper complexes were foundt to have antimicrobial activity against gram-positive bacteria only.

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

• 한국식품영양과학회지
• /
• 제32권3호
• /
• pp.320-324
• /
• 2003

단백질 구성 아미노산 분석을 위한 효과적인 가수분해 방법을 찾기 위하여 0.3% tryptamine을 함유한 6M formic acid와 6M HCI을 표준 아미노산과 단백질 표준품인 bovine serumn albumin 가수분해에 적용하여 표준아미노산의 회수율과 bovine serum albumin의 아미노산 조성을 분석하였고 GC에 의한 효과적인 아미노산 분석을 위하여 새로운 유도체인 butylthiocarbamyl-trimethylsilyl(BTC-TMS)유도체를 개발하여 분석한 결과는 다음과 같았다 표준아미노산의 회수율은 6M formic acid에 의한 가수분해방법이 6M HCI에 의한 가수분해 방법보다 상당히 정확하였고 특히 산 가수분해에서 tryptamine의 존재하에서도 잘 파괴되는 tryptophan의 경우 formic acid가수분해가 HCI가수분해보다 1.5배정도 높은 회수율을 보였다. Bovine serum albumin의 아미노산 조성을 583 아미노산 잔기로 환산하여 나타내었을 경우도 formic acid에 의한 가수분해가 HCI가수분해 경우보다 훨씬 정확하였고 이 때 tryptophan의 회수율도 훨씬 높게 나타났다. 다만 서열분석에서 분석되지 않는 cystine이 formic acid 가수분해시 분석되고 있어 이에 대한 정확한 검정이 필요하였다. BTC-TMS 유도체는 GC분석시 극성이 다소 낮은 DB-l7 column으로 분리가 잘되었고 재현성도 좋았으나 GC분석을 위한 대부분의 유도체에서와 마찬가지로 몇 가지 아미노산에서 두 개의 peak로 나타나는 결점이 있었다.

• 한국조리학회지
• /
• 제23권7호
• /
• pp.42-49
• /
• 2017

This study was conducted to determine the nutritional value of domestic cherry tomato varieties (Summerking, Qutiquti, and Minichal). The levels of amino acids, amino acid derivatives, and ${\gamma}-aminobutyric-acid$ (GABA) were analyzed using ion chromatography. In domestic cherry tomatoes, eighteen free amino acids were found including L-glutamic acid (L-Glu), L-glutamine (L-Gln), and L-aspartic acid (L-Asp). L-Glu was the most abundant amino acid, ranging from 1,533.17 mg/100 g to 1,920.65 mg/100 g (dry weight). The next abundant amino acids were L-Gln, ranging from 784.68 mg/100 g to 1,164.36 mg/100 g and L-Asp, ranging from 320.73 mg/100 g to 387.22 mg/100 g. Domestic cherry tomatoes contained eight essential amino acids except tryptophan and the total essential amino acid content was 297.30~432.43 mg/100 g (dry weight), which was 8.92~10.61% of total free amino acid. Several amino acid derivatives were found: L-carnitine (L-Car), hydroxylysine (Hyl), o-phosphoethanolamine (o-Pea), phosphoserine (p-Ser), ${\beta}-alanine$ (${\beta}-Ala$), N-methyl-histidine (Me-His), ethanolamine ($EtNH_2$), and L-citrulline (L-Cit). L-Car, transporting long-chain fatty acid into mitocondrial matrix, was the most abundant amino acid derivative in all domestic cherry tomatoes. A high level of GABA (313.18~638.57 mg/100 g), known as a neurotransmitter, was also found in all three domestic cherry tomatoes. These results revealed that domestic cherry tomatoes have a good balance of nutrient and bioactive compounds. Therefore, cherry tomatoes can be used as a functional food material.

• KSBB Journal
• /
• 제30권4호
• /
• pp.197-201
• /
• 2015

Liquid chromatographic enantiomer separation of ${\alpha}$-amino acids and their methyl and ethyl esters as fluorenylmethoxycarbonyl (FMOC) derivatives was performed using a recently developed chiral column (Chiralpak IE) based on polysaccharide derivative under simultaneous UV detection and fluorescence detection. The degree of enantiomer separation of ${\alpha}$-amino acid esters as FMOC derivatives is generally higher than that of the corresponding ${\alpha}$-amino acids. Especially, ${\alpha}$-amino acid methyl esters showed the greatest enantioseparation. As this method developed in this study can be applied to determine the chemical and optical purity of ${\alpha}$-amino acids and esters, it is expected to be quite useful for their chiral separation using Chiralpak IE.

• Bulletin of the Korean Chemical Society
• /
• 제17권4호
• /
• pp.314-321
• /
• 1996

Isoxazolidine derivatives 7 and 8 were synthesized from N-benzyl-C-(2-benzyloxyethyl)nitrones by 1,3-dipolar cycloaddition with ethyl crotonate. The isoxazolidine derivatives were converted to β-amino acid esters 9a and 9b by reduction with zinc in acetic acid. The β-amino acid esters were reacted with methylmagnesium bromide to give the 2-azetidinones (13a, 13b). The benzyl group of 2-azetidinones were removed by Birch reduction. The products were oxidized with PDC to give 3-[1-(t-butyldimethylsilyloxy)ethyl]-4-carboxymethyl-2-azetidinone derivatives (2a, 2c).