• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.803-804
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• 1995

• Bulletin of the Korean Chemical Society
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• v.21 no.10
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• pp.1000-1004
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• 2000

• 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

• Bulletin of the Korean Chemical Society
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• v.21 no.2
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• pp.207-210
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• 2000

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.339-341
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• 1992

• Archives of Pharmacal Research
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• v.27 no.8
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• pp.811-815
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• 2004

Coumarin and its derivatives occur widely in nature. Many attempts were made for synthesis of various coumarin derivatives because of their interesting biological activities. In this study, solid phase synthetic approach of 3-(4-hydroxyphenyl)coumarin was achieved for combinatorial synthesis of substituted 3-phenylcoumarin analogues. Starting from 4-hydroxyphenylacetic acid methyl ester, release of 3-(4-hydroxypnehyl)coumarin from polymer support was accom-plished.

• The Korean Journal of Zoology
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• v.39 no.3
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• pp.266-272
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• 1996

Experiments were carried out to ascertain whether gonadotropin or a phorbol ester (12-O-tetradecanoyl phorbol-13-acetate, TPA) induces oocyte ovulation and stimulates prostaglandin synthesis by Rana ovarian follicles in vitro. Rana nigromaculata collected from underground in spring were utilized for the present experiment. Treatment of frog pituitary homogenate (FPH) or TPA to ovarian fragments in culture induced oocyte ovulation in a dose dependent manner and stimulated prostaglandin F2a (PGF$_2$$\alpha$ synthesis. Both treatruents were more effective in inducing the ovulation and PGF$_2$$\alpha$ secretion by the follicles obtained in May than those in April. A Protein kinase C inactivator, 1-(5-isoquinolinyl-sulfonyl)-2-methyl-piperazine (H-7), or cyclooxygenase inhibitor, indomethacin (IM) suppressed the FPH- or TPA-induced PGF$_2$$\alpha$ production, but IM failed to suppress the FPH- or TPA-induced ovulation. Time course of oocyte ovulation and PGF$_2$$\alpha$ secretion by FPH and TPA treatments were very similar to each other. FPH stimulated progesterone secretion by the follicle but TPA failed to do so. Taken together, the data presented here suggest that protein kinase C (PKC) in follicle play a role in the ovulation process of Rana nigromaculata, probably via prostaglandin synthesis.

• Journal of the Korean Chemical Society
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• v.19 no.5
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• pp.367-374
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• 1975

Glycine residue in N-X-glycylphenylalanine methyl ester(X = trifluoroacetyl or acetyl) was converted into aspartic acid derivative by a photoalkylation reaction. The reaction was induced with 350 nm lamp using a combination of diacetyl/di-t-butyl peroxide (DBP) as the photoinitiator, and acetic anhydride as the alkylating agent. In the thermal reaction with DBP and acetic anhydride, the same alkylation reaction of the dipeptide was observed. From this thermal alkylation reaction the photoalkylation reaction is also thought to undergo via free radical mechanism.

• Journal of the Korean Applied Science and Technology
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• v.6 no.2
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• pp.53-58
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• 1989

A series of four sodium ${\alpha}-sulfo$ fatty acid allylester oligomers such as sodium ${\alpha}-sulfo$ lauric acid allylester oligomer, sodium ${\alpha}-sulfo$ myristic acid allyl ester oligomer, sodium ${\alpha}-sulfo$ palmitic acid allyl ester oligomer and sodum ${\alpha}-sulfo$ stearic acid allyl ester oligomer were examined for surface tension, defloculation effect and emulsifying power. Also critical micelle concentration (cmc) was evaluated. Consequently, these sodium allyl ${\alpha}-sulfo$ aliphatic carboxylate aligomers show o/w type emulsifying agent and dispersion effect in 1g/100ml soulution.

• 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.