• Title/Summary/Keyword: Active ester

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Metabolic fate of chloramphenicol-ester (Ester형 Chloramphenicol의 생체내 대사에 대하여)

  • 한병훈
    • YAKHAK HOEJI
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    • v.8 no.1
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    • pp.1-5
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    • 1964
  • Present experiment in vivo shows that some conversions of active groups in chloramphenicol residue of ester, that is hydrolytic cleavage of dichloracetamide and glucuronide formation, seem to take place prior to hydrolysis. This result suggest that the enzymatic hydrolysis rate in vitro, is not available as an index for the evaluation of the chlorampherical ester potency.

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Synthesis of Peptides Containing Optically Active 2-Amino-3-Phosphonopropionic Acid (광학 활성 2-Amino-3-Phosphonopropionic Acid의 새로운 합성 방법과 그를 포함하는 펩티드의 합성)

  • Kim Sang Bum;Cho Sung Ki;Han Jeong Sik;Kim Yong Joon;Hong Suk-In
    • Journal of the Korean Chemical Society
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    • v.38 no.7
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    • pp.516-520
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    • 1994
  • New synthetic method of optically active 2-amino-3-phosphonopropionic acid from L-serine was developed and their phosphonotripeptides, phthalylglycylglycyl-2-amino-3-(diethylphosphono)-propionic acid methyl ester and phthalylglycyl-L-phenylalanyl-2-amino-3-(diethylphosphono)propionic acid methyl ester, were synthesized by coupling reaction of amino acids with 2-amino-3-phosphonopropionic acid methyl ester.

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Development of an Isolable Active Ester, Diethyl Thiophosphoryl [(Z)-(2-Aminothiazol-4-yl)-2-(Methoxyimino)acetate (DAMA) for the Synthesis of Cefotaxime

  • Yoon, Man-Young;Lee, Hee-Bong;Shin, Hyun-Ik
    • Bulletin of the Korean Chemical Society
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    • v.32 no.2
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    • pp.407-410
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    • 2011
  • An isolable activated ester, diethyl thiophosphoryl [(Z)-(2-aminothiazol-4-yl)-2-(methoxyimino)acetate (9a, DAMA) was prepared in high purity, which was at least stable for 7 d at $25^{\circ}C$ and 6 months at $5^{\circ}C$. Its reaction with 7-ACA (4) in the presence of tributylamine in i-PrOH provided cefotaxime (1) of high purity in good yield. Preparation of DAMA and its reaction with 7-ACA (4) to 1 was performed in one-pot manner, respectively with minimal unit operations of stirring and filtration.

Antioxident components from Aralia continentalis

  • Kim, Ju-Sun;Kang, Sam-Sik;Park, Jae-Sue
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1998.11a
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    • pp.182-182
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    • 1998
  • The root of Aralia continentalis Kitagawa(Araliaceae) have been used as an analgesic and fever remedy, and for treatment of rheumatism in Chinese medicine, whereas the young leaves are used for salad. An antioxidant activity of the young leaves of A continentalis was determined by measuring lipid peroxide produced when a mouse liver homogenate was exposed to the air at 37$^{\circ}C$, using 2-thiobarbituric acid(TBA) and by evaluation the radical scavenging activity on 1,l-diphenyl-2 picrylhydrazyl (DPPH) radical. Bioassay guided fractionation of MeOH extract isolated six flavonoid compounds as active components from EtOAc fraction. Adenosine and two saponins were isolated from the weak active BuOH fraction. The antioxidant effect by DPPH radical scavenging activity showed that quercetin was the most active among these compounds. Hyperoside and kaempferol were also active, while 6"-O-acetyl astragalin, astragalin, trifolin, adenosine, oleanolic acid 28-O-glucosyl ester and salsoloside C methyl ester were almost inactive. All the compounds were identified by spectroscopic methods.

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Stereoselective Synthesis of (2S,3R)-3-Hydroxyhomoserine Lactone via anti Selective Dihydroxylation of an OBO Group-Protected Vinyl Glycine Analog ((2S,3R)-3-하이드록시호모세린락톤의 입체선택적 합성 : 바이닐글라이신 OBO Ester 유도체의 입체선택적인 이중알콜화 반응)

  • Koh, Moo-hyun;Jeon, Jongho;Kim, Young Gyu
    • Applied Chemistry for Engineering
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    • v.31 no.2
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    • pp.187-192
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    • 2020
  • (2S,3R)-3-hydroxyhomoserine lactone (HSL) has been used as a key intermediate for the synthesis of various biologically active compounds. In this study, we demonstrated an efficient synthesis of HSL via anti selective dihydroxylation of a protected vinyl glycine analog with an oxabicyclo[2.2.2]octyl orthoester (OBO) ester group. Because the acyclic conformation of the substrate was efficiently controlled by the bulky OBO ester group, a diastereoselectivity of > 10 : 1 was obtained in the dihydroxylation reaction without the use of a chiral reagent. By using this result, the target compound 1 can be obtained from commercially available N-Cbz-L-serine 2 in seven steps with an overall yeid of 34%. This result could be applied to the stereoselective synthesis of biologically active molecules containing a vicinal amino diol moiety.

Studies on the Polymeric Surface Active Agent (II);Synthesis Activities of Sodium ${\alpha}-Sulfo$ Fatty Acid Vinyl Ester Oligomers (고분자(高分子) 계면활성제(界面活性劑)에 관(關)한 연구(硏究) (제(第) 2 보(報));나트륨 알파 술폰 지방산(脂肪酸) 비닐에스테르 올리고머류(類)의 계면활성(界面活性))

  • Jeong, No-Hee;Nam, Ki-Dae;So, Boo-Young;So, Hee-Jun
    • Journal of the Korean Applied Science and Technology
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    • v.6 no.1
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    • pp.51-57
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    • 1989
  • A series of four sodium ${\alpha}-sulfo$ fatty vinyl ester oligomers including sodium ${\alpha}-sulfo$ lauric acid vinyl ester oligomer, sodium ${\alpha}-sulfo$ myristic acid vinyl ester oligomer, sodium ${\alpha}-sulfo$ palmitic acid vinyl ester oligomer and sodium ${\alpha}-sulfo$ stearic acid vinyl ester oligomer were examined for surface activities such as surface tension, foaming power, foam stability, emulsifying power, dispersion effect, solubilization of orange OT. The critical micelle concentration(CMC) was also evaluated. Consequently, these sodium ${\alpha}-sulfo$ fatty acid vinyl ester oligomers were shown to have a good cohesive power and dispersion effect.

Studies on the Polymeric Surface Active Agent (I);Synthesis of Sodium ${\alpha}-Sulfo$ Fatty Acid Vinyl Ester Oligomers (고분자(高分子) 계면활성제(界面活性劑)에 관(關)한 연구(硏究)(제(第) 1 보(報));나트륨 알파 술폰 지방산(脂肪酸) 비닐에스테르 올리머고류(類)의 합성(合成))

  • Jeong, No-Hee;No, Sueng-Ho;Nam, Ki-Dae;So, Boo-Young
    • Journal of the Korean Applied Science and Technology
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    • v.6 no.1
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    • pp.21-26
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    • 1989
  • Four fatty acid vinyl esters were synthesized by transesterification between vinyl acetate and lauric acid, myristic acid, palmitic acid, stearic acid, respectively. Fatty acid vinyl ester oligomers were prepared from polymerization of four fatty acid vinyl esters in the presence of potassium persulfate in methanol. The ${\alpha}-sulfonation$ of these four fatty acid vinyl ester oligomer were carried by direct addition of sulfur trioxide. Especially, molecular weights of sodium ${\alpha}-sulfo$ fatty acid vinyl ester oligomers were measured by boiling point method.

Synthesis and Biopharmaceutical Studies of Cefazolin Butyrolactone Ester, a Novel Prodrug of Cefazolin (Cefazolin Butyrolactone Ester의 합성 및 생물약제학적 연구)

  • 이진환;조행남;최준식
    • YAKHAK HOEJI
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    • v.47 no.5
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    • pp.331-338
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    • 2003
  • A butyrolactone ester of cefazolin (CFZ-BTL) was synthesized by the esterification of cefazolin (CFZ) with $\alpha$-bromo-${\gamma}$-butyrolactone. The synthesis was confirmed by the spectroscopic analysis. The CFZ-BTL was more lipophilic than the CFZ when assessed by n-octanol/water partition coefficients at various pH. The CFZ-BTL itself did not show any antimicrobial activity in vitro, but after oral administration of CFZ-BTL to rabbits, exerted significant anti-microbial activity in serum samples when measured by the inhibion zone method in nutrient agar plates, due to conversion of CFZ-BTL to an active metabolite, probably CFZ, in the body. The CFZ-BTL was also converted into CFZ as confirmed by in vitro incubation study, with tissue homogenates (liver, blood and intestine) of rabbits. The liver showed the fastest conversion rate, probably via the hydrolysis mechanism. In vivo metabolism of CFZ-BTL to CFZ was also confirmed in vivo serum samples by HPLC. The oral bioavailability of CFZ-BTL in rabbits was 1.6-fold increased when compared to CFZ, resulting from followed by enhanced lipophilicity increased passive absorption in the intestine.