• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.454-458
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• 2002

Furo[3,2-h]quinoline derivatives were synthesized as a gastric $H^+$/$K^+$-ATPase inhibitors. The oxycyclization of 7 and 8-positions in quinoline potentiated the inhibitory activity, while no significant changes in biological activity were observed by the variation of substituents in furan ring. The several furo[3,2-h]quinoline derivatives were worthy of in vivo investigation for their anti-secretory and anti-ulcer activity.

• YAKHAK HOEJI
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• v.45 no.6
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• pp.570-574
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• 2001

In order to discover new useful NSAIDs, novel N-substituted 1,2-benzisothiazoline-3-one 1,1- dioxide derivatives, which can exhibit potentially antiinflammatory activity were synthesized. 1,2-Benz-isothiazoline-3-one-N-acetic acids 6a, b were obtained from monochloroacetic acid and sodium 1,2-benz-isothiazoline-3-ones in DMF by N-alkylation reaction. N-Substituted 1,2-benzisothiazoline-3-one 1,1-dioxide derivatives 7a-e were synthesized through the coupling of compound 6a, b and several amines (aniline, 2- aminopyridine , 2-aminothiazole, 2-aminotetrazole) with dicyclohexylcarbodiimide in methyl e no chloride.

• YAKHAK HOEJI
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• v.45 no.1
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• pp.1-6
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• 2001

Nine cinmetacin derivatives as potential nonsteroidal analgesic and antiinflammatory compounds were prepared and their analgesic-antiinflammatory activity was compared with cinmetacin. Salicylic acid and phenols were reacted with dicyclohexyl carbodiimide (DCC) to give phenol salicylates (1-4). Cinmetacin was treated with DCC and phenol derivatives to yield cinmetacin esters (5-13). Compounds (5, 7, 8, 10, 12, and 13) showed stronger analgesic activity than cinmetacin, but only compound (5) showed comparable antiinflammatory activity to cinmetacin.

• Archives of Pharmacal Research
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• v.29 no.2
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• pp.123-130
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• 2006

1,4-Naphthoquinones are widely distributed in nature and many clinically important antitumor drugs containing a quinone moiety, such as anthracyclines, mitoxantrones and saintopin, show excellent anticancer activity. In this study, 2- or 6-substituted 5,8-dimethoxy-1,4-naphthoquinone (DMNQ) and 5,8-dihydroxy-1,4-naphthoquinone (DHNQ) derivatives were synthesized, and their cytotoxic activity against L1210 and P388 cancer cells was examined. Their antitumor activity was also assessed in mice bearing S-180 cells in the peritoneal cavity. In comparison with the DMNQ derivatives, the DHNQ derivatives exhibited more potent bioactivities than the DMNQ derivatives against both L1210 and P388 cells in vitro and S-180 cells in vivo. The $ED_{50}$ values of the DHNQ derivatives against P388 cells were in the range of 0.18-1.81 ${\mu}g/mL$ whereas those of the DMNQ derivatives were in the range of 0.26-40.41 ${\mu}g/mL$. The T/C ($\%$) values of the DHNQ derivatives, 8, 17, 18, 19, and 20, were found to be comparable to or even better than that of adriamycin. It was also observed that the 2-substituted derivatives (8, 19, 20) showed better antitumor activity than the 6-substituted derivatives (7, 17, 18) in the mice bearing S-180 cells in the peritoneal cavity.

• Journal of Life Science
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• v.33 no.2
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• pp.169-175
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• 2023

As a protective defensive mechanism against ultraviolet (UV) light exposure in skin tissue, melanocytes produce the pigment melanin. Tyrosinase plays a key role in melanin production in melanocytes. However, the overproduction of melanin can lead to lesions, such as freckles and dark spots. Thus, it is clinically important to find a modulating molecule to control melanogenesis by regulating tyrosinase expression and/or activity. It is known that catechin, a plant flavonoid, can reduce melano- genesis through the downregulation of tyrosinase expression. Here, we tested whether catechin derivatives isolated from the stem bark of Ulmus parvifolia have an effect on melanin production by regulating tyrosinase in mouse melanoma cells and in vitro mushroom tyrosinase. The catechin derivatives used in this study included C5A, C7A, C7G, and C7X. Treatments using these catechin derivatives reduced melanin production in mouse melanoma B16F10 cells in which melanogenesis was stimulated by α-MSH. Notably, the anti-melanogenic effects of catechin derivatives were similar to those of kojic acid, a well-known anti-melanogenic molecule. Both C5A and C7A directly inhibited the activity of tyrosinase isolated from mushrooms in vitro. Furthermore, our in silico computational simulation showed that these two compounds were expected to bind to the active site of tyrosinase, which is similar to kojic acid. In addition, all four catechin derivatives reduced tyrosinase protein expression. In summary, our results showed that catechin derivatives can reduce melanogenesis by regulating tyrosinase activity or expression. Thus, this study suggests that catechin derivatives isolated from U. parvifolia can be novel modulators of melanin production.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.7
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• pp.552-561
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• 2016

In this experimental study, the dynamic stability derivatives of a tailless lambda-shape UAV are estimated from time history data of aerodynamic moments measured from the internal balance while the test model is forced to oscillate at given frequencies and amplitudes. A 3-axis forced oscillation apparatus is designed to induce decoupled roll, yaw, pitch oscillations respectively. The results show that the roll damping derivatives remain stable at the entire range of angle of attack tested, whereas the pitch damping derivatives become unstable beyond $15^{\circ}$ angle of attack. The amplitude and frequency have little impact on roll damping derivatives while the smaller amplitude and frequency of oscillation improves the pitch stability. The yaw damping derivative values are fairly small as expected for a tailless configuration. The results indicate that the proposed methodology and test apparatus area valid for estimating the dynamic stability derivatives of a tailless UAV.

• Journal of the Korean Chemical Society
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• v.38 no.7
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• pp.521-525
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• 1994

New cephalosporin antibiotics, 7-[(3,4-dihydro-6-methoxycarbonyl-2,2-dimethyl-2H-1,4-thiazin-3-yl)acetamido]-3-heterocyclothiomethyl-3-cephem-4-carboxylic acid derivatives(2a∼2d) were synthesized. Antibacterial activities of these new cephalosporin derivatives and the relationship between their structures and their activities were examined. Among them,7-[(3,4-dihydro-6-methoxycarbonyl-2,2-dimethyl-2H-1,4-thiazin-3-yl)acetamido]-3-[(2-methyl-1,3,4-thiadiazol-5-yl)thiomethyl]-3-cephem-4-carboxylic acid exhibited the broad antibacterial activities against Gram(+) and Gram(-) bacteria.

• Analytical Science and Technology
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• v.12 no.3
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• pp.203-208
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• 1999

The ion-pair high performance liquid chromatographic elution behavior of salicylic acid and its derivatives was studied with measuring capacity factor, k', changing the concentration of ion-pairing reagent (tetrabutylammonium chloride, TBACl) in mobile phase. As a result, it was found that k' of the samples increase at pH 7.2 as the TBACl concentration increases. The derivatives of salicylic acid were separated each other at an optimum mobile phase condition which was found from the observation of the retention behavior. The optimum mobile phase condition was methanol solution($MeOH:H_2O_2$ 30:70) containing 20 mM TBACl for the determination of salicylic acid and methanol solution($MeOH:H_2O_2$ 20:80) containing 40 mM TBACl for p-aminosalicylic acid at pH 7.2. The method has been applied for the analysis of the contents of salicylic acid derivatives in an aspirin tablet and a tuberculosis curing agent.

• Archives of Pharmacal Research
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• v.12 no.1
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• pp.1-4
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• 1989

6-Arylamino-3,7-dihydro-3,7-dimethy-2-oxo-1H-purine and 2-arylimino-6-arylamino-3,7-dihydro-3,7-dimethyl-1H-purine were obtained in a one-pot reaction when 3,7-dihydro-3,7-dimethyl-1H-purine-3,6-dione, phosphorus pentaoxide, triethylamine hydrochloride and appropriate amine amino are heated at $170^{\circ}$. Some derivatives were tested for their antitumor activity.

• Archives of Pharmacal Research
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• v.29 no.7
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• pp.556-562
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• 2006

Ten semi-synthetic derivatives of asiatic acid were prepared and their wound healing effects were evaluated by employing a tensile strength assay and a wound area assay. Among them, ethoxymethyl 2-oxo-3,23-isopropylidene-asiatate (12) showed the strongest and the fastest wound healing activity. Furthermore, it left the smallest scar after healing.