• Archives of Pharmacal Research
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• 제17권3호
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• pp.139-144
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• 1994

A series of 6-(N-aylamono)-7-chloro-5, 8-quinolinedione derivatives was newly synthesized for the evaluation of antifugal activities. 5-Amino-8-hydroxy-quinoline (II) was treated with $KCLO_3$ in HCl to give 6,7-dichloro-5,8-quinolinediones (III). 6-(N-Arylamino)-7-chloro5,8-quinolinediones 1-13 were prepared by regioselective nucleophilic substitution of III with arylamines. In the presence of $CeCl_3$, the N-arylamono groups were introduced at the 6-position of 5,8-quinolinedione ring by the regioselective substitution. These derivatives 1-12 were tested for natifungal and also antibacterial activites, in vitro, against Canadida albicans, Aspergillus nier, Tricophyton mentagrophytes, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coil. The MIC values were determined by the two-fold agar/steak dilution method. Newly obtained 6-(N-arylamino)-7-chloro5,8-quinolinedione derivatives showed potent antifungal and antibacterial activities. Among these derivatives, 1,3,5,7,8 and 9 showed more potent antifungal activities than fluconazole and griseofulvin. Also most of derivatives were found to be more active than ampicillin against gram-positive bacteria. 1 and 7 showed the very potent antifungal activities. 1 was the most efective in preventing the growth of Candida albicans, Aspergillus niger, Tricophyton mentagrophytes, Bacillus subtills and Staphylococcus aureus at MIC $1.6\;\mu{g/ml}$.

• Environmental Analysis Health and Toxicology
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• 제22권3호
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• pp.219-225
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• 2007

A series of new derivatives of 1-(5-oxohexyl)-3,7-dimethylxanthine has been prepared for the treatment of the vascular dementia. To investigate hepatoprotective effect of these derivatives, the serum biochemical activity and the histological change of liver tissue were evaluated in carbon tetrachloride ($CCl_4$) treated rats. The activities of aspartate aminotransferase and alanine aminotransferase and the activities of total cholesterol, triglyceride and total bilirubin in 5-oxohexyl-3,7-dimethylxanthine derivatives pretreated rats were significantly decreased compared to the $CCl_4$ only treated rats but the content of glutathione S-transferase was increased compared to the $CCl_4$ only treated rats. These results indicated that 5-oxohexyl-3,7-dimethylxanthine derivatives have hepatoprotective effect in $CCl_4$ intoxicated rats.

• Archives of Pharmacal Research
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• 제19권6호
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• pp.535-542
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• 1996

Seven isoazamitosene derivatives, mitomycin analogues, were synthesized and tested for cytotoxicities against leukemia and gastric cancer cell lines. Preparation of a pyrrolo[1, 2-a]benzimidazole (3) (azamitosene ring system) was completed by utilizing the Lewis acid-catalized cyclization, with .omicron.-chloronitrotoluene as the starting material. Nitration of 3 produced a mixtue of two isomers (5-nitro isomer (4) and 7-nitro isomer (5)) in product ratio of 36 : 52. 4 was directly converted into quinone (7) by reduction and Fremy oxidaton. Finally, quinone derivatives (8, 9, 10, and 11) were synthesized by 1, 4-addition of 7 with cyclic secondary amines. From above-mentioned 5, 8-nitro compound (15) was prepared in 4 steps. At pH 3, Fremy oxidation of 15 produced quinone (16), whereas iminoquinone derivatives (17a and 17b) at pH 7. Isoazamitosene derivatives (8, 9, 10, and 11), containing cyclic amino groups at the 7-position, showed potent cytotoxicity on P388, SNU-1, and KHH tumor cell lines. Among them, 8 had stronger cytotoxicity against SNU-1 cell line than mitomycin and adriamycin. Considering these results, isoazamitosene derivatives may had unique cytotoxicity profiles. However, isoiminoazamitosene derivatives (17a and 17b) revealed very weak cytotoxicity.

• Wind and Structures
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• 제7권3호
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• pp.187-202
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• 2004

Wind tunnel experiments are often performed for the identification of aeroelastic parameters known as flutter derivatives that are necessary for the prediction of flutter instability for flexible structures. Experimental determination of all the eighteen flutter derivatives for a section model facilitates complete understanding of the physical mechanism of flutter. However, work in the field of identifying all the eighteen flutter derivatives using section models with all three degree-of-freedom (DOF) has been limited. In the current paper, all eighteen flutter derivatives for a streamlined bridge deck and an airfoil section model were identified by using a new system identification technique, namely, Iterative Least Squares (ILS) approach. Flutter derivatives of the current bridge and the Tsurumi bridge are compared. Flutter derivatives related to the lateral DOF have been emphasized. Pseudo-steady theory for predicting some of the flutter derivatives is verified by comparing with experimental data. The three-DOF suspension system and the electromagnetic system for providing the initial conditions for free-vibration of the section model are also discussed.

• 약학회지
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• 제43권1호
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• pp.28-32
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• 1999

Four derivatives of kojic acid were synthesized and their inhibitory activities against tyrosinase were evaluated. The C-2 hydroxymethyl and C-7 hydroxyl of kojic acid were replaced by carboxylate and amine, respectively. These derivatives were coupled to L-phenylalanine, producing two amide compounds. The carboxylate derivative (3), its amide compound (5), and the amine derivative (7) were weak inhibitors. The amide compound (9) where amine derivative (7) coupled to L-phenylalanine showed strong inhibitory activity ($IC_{50}=24.6{\;}{\mu}M$) comparable to kojic acid.

• Asian Pacific Journal of Cancer Prevention
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• 제16권13호
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• pp.5371-5376
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• 2015

Berberine (B1), isolated from stems of Coscinium fenestratum (Goetgh.) Colebr, was used as a principle structure to synthesize three phenolic derivatives: berberrubine (B2) with a single phenolic group, berberrubine chloride (B3) as a chloride counter ion derivative, and 2,3,9,10-tetra-hydroxyberberine chloride (B4) with four phenolic groups, to investigate their direct and indirect antioxidant activities. For DPPH assay, compounds B4, B3, and B2 showed good direct antioxidant activity ($IC_{50}$ values=$10.7{\pm}1.76$, $55.2{\pm}2.24$, and $87.4{\pm}6.65{\mu}M$, respectively) whereas the $IC_{50}$ value of berberine was higher than $500{\mu}M$. Moreover, compound B4 exhibited a better DPPH scavenging activity than BHT as a standard antioxidant ($IC_{50}=72.7{\pm}7.22{\mu}M$) due to the ortho position of hydroxyl groups and its capacity to undergo intramolecular hydrogen bonding. For cytotoxicity assay against human fibrosarcoma cells (HT1080) using MTT reagent, the sequence of $IC_{50}$ value at 7-day treatment stated that B1 < B4 < B2 ($0.44{\pm}0.03$, $2.88{\pm}0.23$, and $6.05{\pm}0.64{\mu}M$, respectively). Berberine derivatives, B2 and B4, showed approximately the same level of CAT expression and significant up-regulation of SOD expression in a dose-dependent manner compared to berberine treatment for 7-day exposure using reverse transcription-polymerase chain reaction (RT-PCR) assays. Our findings show a better direct-antioxidant activity of the derivatives containing phenolic groups than berberine in a cell-free system. For cell-based system, berberine was able to exert better cytotoxic activity than its derivatives. Berberine derivatives containing a single and four phenolic groups showed improved up-regulation of SOD gene expression. Cytotoxic action might not be the main effect of berberine derivatives. Other pharmacological targets of these derivatives should be further investigated to confirm the medical benefit of phenolic groups introduced into the berberine molecule.

• The Journal of Asian Finance, Economics and Business
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• 제7권4호
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• pp.51-58
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• 2020

The study aims to investigate the relationship between hedging with derivatives and subsequent firm-level stock price crash risk. Our sample consists of KOSPI- and KOSDAQ-listed companies from 2004 to 2014. The total firm-year observation is 4,886. We find that hedging with derivatives is related to greater possibilities of crash risk. The results suggest that the complexity of economic and financial reporting for derivatives may aggravate the company's information opacity, ultimately increasing the crash risk. We contribute to the growing body of literature on hedging with derivatives. Academics and practitioners have debated on whether or not hedging enhances transparency or rather makes the information environment more opaque. Theoretical research on the role of corporate hedging on information environment shows that hedging enhances earnings informativeness. Meanwhile, pieces of anecdotal and empirical evidence show that the economic and financial reporting complexity of derivatives can harm information transparency. Our results shed light on the question of whether and how hedging with derivatives affects information environment by examining the relationship between hedging with derivatives and crash risk. Furthermore, our findings provide useful insights for policymakers and practitioners. Specifically, our results raise a need for a more transparent disclosure on corporate hedging activities with derivatives.

• Bulletin of the Korean Chemical Society
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• 제7권5호
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• pp.380-384
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• 1986

The infrared intensities of $CH_{4}$ and $CD_{4}$ are analyzed. The experimental dipole moment derivatives thus obtained are compared with corresponding values from the molecular orbital calculations. The theoretical results are analyzed for the charge-charge flux-overlap(CCFO) electronic contributions to the dipole derivatives.

• 약학회지
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• 제41권4호
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• pp.473-479
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• 1997

New cephalosporin antibiotics, 7-[(3,4-dihydro-6-methoxycarbonyl-2,2-dimethyl-2H-1,4-thiazin-3-yl)acetamido]-3-substituted-3-cephem-4-carboxylic acid derivatives 2a-2d, 7 -[(3,4-dihydro-6-ethoxycarbonyl-2,2-dimethyl-2H-1,4-thiazin-3-yl)acetamido] -3-substituted-3-cephem-4-carboxylic acid derivatives 3a-3d and 7-[(3,4-dihydro-6-methoxycarbonyl-2,2-dimethyl-2H-1,4-thiazin-3-yl-1-(S)-oxide)acetamido]-3-substituted-3-cephem-4-carboxylic acid derivatives 4a-4d 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-methoxycaronyl-2,2-dimethyl-2H-1,4-thiazin-3-yl-1-(S)oxide)-acetamido]-3-[(1,2,3-triazol-5-yl)thiomethyl]-3-cephem-4-carboxylic acid 4d exhibited the antibacterial activities against Gram(+)and Gram(-) bacteria.

• 대한화학회지
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• 제38권8호
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• pp.603-607
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• 1994

새로운 cephalosporin 항생물질인 7-[(3,4-dihydro-6-methoxycarbonyl-2,2-dimethyl-2H-1,4-thiazin-3-yl)acetamido]-3-[(substituted pyrimidin-2-yl)thiomethyl]-3-cephem-4-carboxylic acid derivatives(2a∼2d)유도체들을 합성하였다. 7-ACA의 3-위치에는 pyridinylthiomethyl기를 도입시키고, 7-위치에는 thiazine를 치환시켜서 구조 변화에 대한 항균 활성을 측정하였다. 그 결과 이들 유도체들은 기준물질인 cefotaxim보다 낮은 항균력을 나타내었다.