• 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.

• 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.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.646-651
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• 1990

New optically active phosphonodipeptides were synthesized by coupling reaction of amino acids with 2-amino-3-(diethylphosphono)propionic acid methyl ester, prepared from L-serine.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• Bulletin of the Korean Chemical Society
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• v.18 no.11
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• pp.1208-1210
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• 1997