• Bulletin of the Korean Chemical Society
• /
• 제16권4호
• /
• pp.305-309
• /
• 1995

The enantiomeric separation of several amino acid derivatives by reversed-phase liquid chromatography using two (R)-and (S)-naphthylethylcarbamate-β-cyclodextrin(NEC-β-CD) bonded stationary phases was studied to illustrate the chiral recognition model of the enantiomeric separation. The retention and enantioselectivity of the chiral separations with (R)-and (S)-NEC-β-CD bonded phases were compared with similar separations with the native β-CD stationary phases. Especially, the enantioselectivity and elution orders between the derivatized amino acid enantiomers are carefully examined. These results can be illustrated by the chiral recognition models involving inclusion complexation, π-π interaction, and/or hydrophobic interaction. Inclusion complexation and hydrophobic interaction of the naphthyl group of the NEC moiety seem to be major chiral recognition components in the enantiomeric separation of 2,4-dinitrophenyl amino acids and dabsyl amino acids on (R)-and (S)-NEC-β-CD columns. For dansyl amino acids, only the inclusion complexation is the dominant factor. Three different chiral recognition models containing π-π interaction, inclusion complexation and hydrogen bonding were proposed for the separation of the 3,5-dinitrobenzoyl amino acid enantiomers, depending on the size and shape of amino acids.

• Journal of Microbiology and Biotechnology
• /
• 제11권2호
• /
• pp.281-286
• /
• 2001

Since the number of amino groups which are exposed by deacetylation of acetyl-D-glucosamine influences antimicrobial activity, a chitosan oligosaccharide (COS) derivative by N-conjugation of COS with asparagine, an amino acid with two amino groups, was synthesized and the antimicrobial effect on E. coli growth was compared with other COS derivatives which were N-conjugated with glycine, alanine, aspartic acid, cysteins, an methionine, and unmodified COS. The structure of asparagine N-conjugated COS (Asn-COS) derivative was identified by using a FT-IR, $^{13}C\;FT-NMR$, and an elemental analyzer. The antimicrobial activity of Asn-COS against E. coli growth was significantly improved as compared to the other COS derivatives as well as COS itself. This means that Asn-COS with two positive charges strongly interacts with the carboxyl negative charges on the bacteria cell wall. The results for Asn-COS were as follows: 100% bactericidal activity, 0.002% MIC, and no growth of E. coli during 3 days of culture time, suggesting that Asn-COS may be useful as a new antibiotic agent.

• 약학회지
• /
• 제32권4호
• /
• pp.245-250
• /
• 1988

Naphthoquinone derivatives have been found to be anticoagulant. In this report, several new 2-chloro-3-(N-arylamino)-naphthoquinone derivatives were synthesized in oder to develope mild anticoagulant. 2, 3-dichloro-1, 4-naphthoquinone was reacted with p-aminobenzoic acid, m-aminobenzoic acid, toluidine, m-nitroaniline, sulfanilamide, sulfathiazole, sulfaguanidine, phenetidine, 2-aminopyrimidine and 3-amino-5-methylisoxazole in EtOH or AcOH afford 2-chloro-3-(p-carboxy anilino)-naphthoquinone (1), 2-chloro-3-(m-carboxyanilino)-naphthoquinone (2),2-chloro-3-(toluidino)-naphthoquinone (3),2-chloro-3-(m-nitroanilino)-naphthoquinone (4), 2-chloro-3-(4-sulfanilanilino)-naphthoquinone (5), 2-chloro-3-(4-sulfathiazolino)-naphthoquinone (6),2-chloro-3-(4-sulfaguanidino)-naphthoquinone (7),2-chlro-3-(phenetidino)-naphthoquinone (8), 2-chloro-3-(pyrimidine-2-amino)-naphthoquinone (9) and 2-chloro-3-(5-methylisoxazole-3-amino)-naphthoquinone (10) in good yield.

• Bulletin of the Korean Chemical Society
• /
• 제22권9호
• /
• pp.958-962
• /
• 2001

The chiral amine auxiliary mediated stereoselective alkylation reactions of glycinamides 1-6 and 15-17 using phase transfer catalyst (PTC) for liquid-solid extraction are described. The secondary N-(diphenylmethylene) glycinamides 1, 2 and 3 give better selectivities and yields than tertiary N-(diphenylmethylene) glycinamides 4, 5 and 6. Alkylation of the glycinamide 1 and 2 using 18-Crown-6 as a PTC in toluene at $-40^{\circ}C$ gives best selectivities and yields. Alkylations of N-(4-chlorophenylmethylene)glycinamides 15, 16 and 17 under same PTC conditions give $\alpha$, $\alpha-disubstituted$ amino acid derivatives 18, 19 and 20 with low diastereoselectivities.

• 한국응용과학기술학회지
• /
• 제3권1호
• /
• pp.43-47
• /
• 1986

1.2-bis(aminoacyl)hydrazine derivatives and dipeptides were synthesized by conventional peptide synthesis procedures. Their antioxidant activity were inverstigated by over-storage test using corn oil as substrte. 1.2-bis (aminoacyl) hydrazine derivatives and dipetides containing hydrophobic side chain amino acid showed higher antioxidant activity. A free N-terminal amino group was also found to be important for the appearance of antioxidant activity. 1.2-bis (aminoacyl) hydrazine derivatives showed higher antioxidant activity than dipeptides. Antimicrobial activites of dipeptides and 1.2-bis (aminoacyl) hydrazine derivatives were also examined by the paper disc method. All of these compounds had shown no antimicrobial activity.

• Archives of Pharmacal Research
• /
• 제23권6호
• /
• pp.564-567
• /
• 2000

The use of amino acid derivatives as building blocks in peptide synthesis is increasingly being recognized as a potential route for the development of pharmaceutical agents. Side chain protection of polyfunctional amino acids such as Ser, Thr, Tyr is viewed as being particularly important. Although these derivatives are commercially listed, they are expensive and not widely available. We describe here a practical large-scale synthesis of t-butyl introduced D-serine, one of the building blocks of zoladex, a peptide drug.

• Applied Biological Chemistry
• /
• 제35권2호
• /
• pp.132-138
• /
• 1992

Methylisothiocyanate에 의한 단백질의 아미노산 배열 결정시 순차적으로 분리되어 나오는 methylthiohydantion 아미노산을 기체 크로마토그라피로 효과적으로 정성 및 정량하기위하여 새로운 silylating reagent인 N-methyl-N-(tert.-butyldimethylsily)trifluoroacetamide를 사용하여 N-tert.-butyldimethylsily MTH 유도체로 silylation 한 후 HP-1 capillary column으로 분석하였다. Cystine을 제외한 21개의 단백질 구성 아미노산을 동정할 수 있었고 지금까지 packed column에서 TMS 유도체로 동정할 수 없었던 arginine도 분리 동정되었다. 2개 이상의 peak를 나타낸 것으로는 hydroxyproline, proline, isoleucine, glycine 및 tyrosine이었고 이중 hydroxyproline은 많은 수의 peak들로 분리되었다. Lysine, histidine 및 arginine은 주입량 $5.0\;nmole{\sim}15.0\;nmole$의 범위에서 나머지는 $2.5\;nmole{\sim}7.5\;nmole$의 범위에서 상관관계를 측정한 결과 고도의 직선 상관관계를 나타내었다(p<0.001). TMS 유도체에 의한 분석은 많은 불순 peak들 때문에 정량분석에 이용할 수 없었다.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.339.1-339.1
• /
• 2002

Since two selective COX-2 inhibitors. celecoxib and rofecoxib, showed good biological activity as antiinflammatory agents. many medicinal chemists are interested in specific COX-2 inhibitors. The distinguished feature of these drugs is that the 5-membered heterocycle ring is substituted with two aryl groups. Therefore, in this study, we designed a new hydantoin derivatives via the reaction of unnatural amino acids as selective COX-2 inhibitors, In systematically steps. 5-phenyl-1 (or substituted) hydantoin derivatives were prepared through esterification. bromination, C-N bond formation, cyclization from phenyl acetic acid. Particularly. a novel hydantoin ring was converted from unnatural amino acids with potassium isoyanate. In last step. the final analogs were synthesized the substitution at 3-position with alkyl reagents.

• Bulletin of the Korean Chemical Society
• /
• 제20권1호
• /
• pp.106-108
• /
• 1999

• Bulletin of the Korean Chemical Society
• /
• 제19권7호
• /
• pp.715-717
• /
• 1998