• Journal of Biomedical Engineering Research
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• v.15 no.1
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• pp.89-96
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• 1994

The ether-type chitin derivatives were synthesized by reacting chitin with chloropropane, propylene oxide and chloropropane diol to form propyl chitin(PPC), hydroxypropyl chitin(HPC) and dihydroxypropyl chitin(DHPC). These derivatives formed a lyotropic cholesteric liquid crystallinity in concentrations over 30 wt% solution in formic acid (99%). Cast films from liquid crystalline solutions were degraded by lysozyme in pseudo-extra cellular tluid(PECF)solutions, at pH 1.2, pH 6.7 and pH 8.2. Three ether-type chitin derivatives rapidly degraded within the first week, and showed a decreased mechanical strength in neutral pH range. Dihydroxypropyl chitin showed the best biodegradation among these derivatives.

• YAKHAK HOEJI
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• v.35 no.1
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• pp.7-10
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• 1991

For the purpose of developing of anticariogenic agents, P-phenylphenol derivatives were synthesized and determined their antibacterial activities against a cariogenic bacterium, Streptococcus mutans. Among synthetic compounds, 2-nitro-6-bromo-p-phenylphenol showed as potent antibacterial activity as magnolol and honokiol.

• Archives of Pharmacal Research
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• v.17 no.2
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• pp.119-123
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• 1994

The synthesis of 3a, 3b, 7a fro Benzpthiazepinone and 1,4-dihyropyridine derivatives is described. Benzothiazepinone nad 1,4-dihydropyridine derivatives were prepared according to literature procedure. The key reactions involve esterification and amidation of benzothize-pinone nad 1,4-dihydropyridine derivatives.

• Bulletin of the Korean Chemical Society
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• v.17 no.4
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• pp.314-321
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• 1996

Isoxazolidine derivatives 7 and 8 were synthesized from N-benzyl-C-(2-benzyloxyethyl)nitrones by 1,3-dipolar cycloaddition with ethyl crotonate. The isoxazolidine derivatives were converted to β-amino acid esters 9a and 9b by reduction with zinc in acetic acid. The β-amino acid esters were reacted with methylmagnesium bromide to give the 2-azetidinones (13a, 13b). The benzyl group of 2-azetidinones were removed by Birch reduction. The products were oxidized with PDC to give 3-[1-(t-butyldimethylsilyloxy)ethyl]-4-carboxymethyl-2-azetidinone derivatives (2a, 2c).

• Archives of Pharmacal Research
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• v.17 no.6
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• pp.483-486
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• 1994

A series of 6-[N-(halophenyl)amino]-7-chloro-5, 8-quinolinedione derivatives 1-10 were tested for antifungal susceptibilities, in vitro, aginst pathogenic Candida species such as C. ablbicans, C glabrata, C. krusei, C. parapsilosis and C. tropicalis. The MICs were determined by the standard macrodilution techniques, according to the NCCLS 1992 guidelines. The 6-[N-(halo-standard macrodilution techniques, according to the NCCLS 1992 gidelines. The 6-[N-(halo-phenyl)amino]-7-chloro-5, 8-quinolinedione derivatives showed generally potent antifungal activities against pathogenic Candida species. Among them, derivative 1, 2, 5, and 7 showed more potent antifungal activities than kietoconazole. All derivatives 1-10 had specially potent activities against C. torpicalis. Derivative 1 and 2 containing 9N-3, 4-dihalo-phenyl)amino moiety exhibited the potent antifugal activities. Derivative 2 with (3, 4-dichlorophenyl)amino substitutent was the most effetive in preventing the growth of Candida species at MICs 4.mu.g/ml respectively.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1837-1838
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• 2010

• YAKHAK HOEJI
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• v.58 no.1
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• pp.21-27
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• 2014

We have developed 8 peptide derivatives as potential MC1R antagonists and their inhibitory effects on ${\alpha}$-MSH induced cell growth in cultured normal human melanocytes (NHM) were investigated. From these experiments, the two most potent peptide derivatives, 5-phenylvaleric acid-(D)His-Arg-Trp-$(Lys)_6NH_2$ (P 6) and 5-phenylvaleric acid-(D)His-Arg-Trp-$(Lys)_9NH_2$ (P 7) were selected for further studies. In ${\alpha}$-MSH depleted NHM cells, we have found that the treatment with 1 ${\mu}M$ of these two peptide derivatives, P 6 and P 7, inhibited the cell proliferation induced by the addition of 1 nM ${\alpha}$- MSH by 70% and 72%, respectively. In NHM cells without previous ${\alpha}$-MSH depletion, 1 ${\mu}M$ treatment in the presence of 10 nM ${\alpha}$-MSH resulted in 70% (P 6) and 80% (P 7) decrease in cell growth and 64% (P 6) and 71% (P 7) reduction in melanin synthesis, respectively. The peptide derivatives P 6 and P 7 were proved to have no apparent cytotoxicity and inhibited the elevation of intracellular cAMP concentration triggered by ${\alpha}$-MSH. In conclusion, our data suggest that the peptide derivatives reported in this study, 5-phenylvaleric acid-(D)His-Arg-Trp-$(Lys)_6NH_2$ (P 6) and 5-phenylvaleric acid-(D)His- Arg-Trp-$(Lys)_9NH_2$ (P 7) strongly antagonize ${\alpha}$-MSH, inhibit cell proliferation and melanin synthesis, and lower the intracellular cAMP concentration, hence have a promising potential as a novel skin lightening agent.

• Journal of the Korean Chemical Society
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• v.64 no.1
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• pp.7-18
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• 2020

An efficient and facile procedure has been developed for the synthesis of novel bichalcone derivatives (4a, 4b). The key step contains the solvent-free aldol synthesis of bichalcones based on quinones. Bichalcones (4a, 4b) were used as precursors for the synthesis of some interesting heterocyclic compounds like, diazepines (5a, 5b), pyrazolo-pyrimidines (7a, 7b), and pyrazoline derivatives (8a, 8b). Moreover, new thioxopyrimidine derivatives (9a, 9b) were furnished and used as a functionalizing agent to produce the triazole-pyrimidines (11, 12) and the carbonitrile derivative (14). All the synthesized compounds were fully characterized using physical and spectral data like, FT-IR, ¹H NMR, ¹³C NMR, and MS. Bichalcones (4a, 4b) and diazepines (5a, 5b) were screened for their anticonvulsant activity, where compounds (4a, 5a, and 5b) revealed potent anticonvulsant activity compared to diazepam. On the other hand, some of the prepared compounds were screened for their antiproliferative activity and they showed significant cytotoxic effects on most of the cancer cell lines with regard to broad spectrum antitumor activity.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.2111-2116
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• 2013

This paper reports substituent effects on the conformational changes in polyaniline (PAni) derivatives. PAni, poly-o-toluidine (POT), and poly-o-anisidine (POA) were formed by potentiodynamic electropolymerization in aqueous solution containing (+)-camphorsulfonic acid (CSA) as a dopant. UV-Vis spectroscopy and cyclic voltammetry measurements revealed that the methyl group showed a greater steric hindrance than the methoxy group. Further, the doping level decreased with increasing steric hindrance. The sign pattern of the circular dichroism (CD) bands for POA was opposite to that for PAni. However, no CD bands were observed in POT. The steric hindrance caused helical inversion, but at a high level of steric hindrance, the helical conformation could not be adopted, because of the reduced doping level. The reduced crystallinity was greatly affected by the decreased doping level. The steric effect influenced the polymer conformation and the doping level, thus determining the optical activity, morphology, and crystallinity of the PAni derivatives.

• Journal of the Korean Chemical Society
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• v.25 no.3
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• pp.199-205
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• 1981

7-Alkyl-1-carboxyphenazine derivatives, bearing butyl or octyl group, were synthesize by the reaction of anthranilic acid with 3-nitroalkylbenzene, prepared from aniline and alcohols as starting materials through alkylation of 3-nitro-4-aminoalkylbenzene. And the products were also identified by elementary analysis, IR and NMR spectra. Surface tension of these derivatives in aqueous solution was determined. And also Antibiotic activity of these derivatives was tested, using Gram positive and negative bacillus and fungi. It showed that the antibiotic activity of these alkyl-substituted 1-carboxyphenazine derivatives was stronger than that of the 1-carboxyphenazine.