• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.169-174
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• 2011

The synthesis of new pyrazolyl and cyclopropyl derivatives of purpurin-18 methyl ester and purpurin-18-N-butylimide 1a, 1b, 2a, 2b and 8 is described. The new compounds were characterized by NMR, UV-vis spectroscopy and mass spectrometry. UV-vis spectra of the new compounds showed long wavelength absorption of ranges 692 - 708 nm ($\lambda_{max}$). Photodynamic effects of the chlorin derivatives 1a, 1b, 2a and 2b were investigated by WST-1 assay in A549 cells, and showed good photodynamic activities with high photocytotoxicity and low cytotoxicity in the dark. In comparison between pyrazolyl and cyclopropyl derivatives, purpurin-18 methyl ester compounds 1a and 1b showed comparable photocytotoxicity result of the cell viabilities, otherwise, pyrazolyl derivative of purpurin-18-N-butylimide 2a showed better cell viabilities than those of cyclopropyl derivative 2b. And cyclopropyl derivative of purpurin-18-N-butylimide 2b showed higher dark cytotoxicity than that of others.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2145-2148
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• 2012

A new thiourea based receptor (1) was synthesized and applied to fluoride ion recognition in acetonitrile solution. Receptor 1 displayed dual changes in absorption and fluorescence emission intensities selectively for fluoride ions. The interaction of 1 with fluoride undergoes a deprotonation process that is confirmed by $^1H$ NMR titration.

• Bulletin of the Korean Chemical Society
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• v.21 no.8
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• pp.774-778
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• 2000

A convenient total synthesis of a new 7-deoxyidarubicinone ivative21,the aglycon of the anticancer anti-biotic idarubicin analogue,is described.Keyfeatures of the synthesis are the Friedel-Crafts acylation and the functionalization of an A-ring si de chain. A synthon 14 for the A and B rings was prepared from intermediate 6 in five steps.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1169-1171
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• 2003

A stable derivative of L-ascorbic acid, 2-O-[(3-aminopropyl)phosphinooxy]-L-ascorbic acid (LAAP), was synthesized in moderate yield and its chemical stability and effects on melanin synthesis were investigated. LAscorbic acid was decomposed completely within about 1 hour, while 93% of LAAP remained even after 10 days. Treatment of L-ascorbic acid and LAAP decreased melanin content in normal human melanocytes to 33.8% and 49.1% of control at 2 mM, respectively. Considering chemical instability of L-ascorbic acid, LAAP is a much better whitening agent.

• Applied Biological Chemistry
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• v.35 no.6
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• pp.470-474
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• 1992

For the further development of thelepin analog as antibiotic agents, we undertook the synthesis of spirobenzopyranone derivative ${\underline{5}}$ as thelepin analog by oxidative phenol coupling. The spirobenzopyranone analog ${\underline{5}}$ showed high activity against Bacillus subtilis (IFO 3108) in $5\;{\mu}g/disc$.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.820-822
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• 2008

Pentacene has excellent semi-conducting characteristics. But pentacene practically used in OTFTs gives rise to problems mainly due to its sensitivity to oxygen and its very low solubility. In order to make up the problems, 6,13-disubstituted pentacene derivative was synthesized and characterized. The properties of the compound were characterized by FT-IR, NMR and we measured the charge transport mobility and the on/off current ratios.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3618-3622
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• 2014

Simple and practical synthesis of natural benzofuran derivative eupomatenoid-6 via Horner-Emmons type condensation as the key step is described. The umpolung property of aldehyde derivative, ${\alpha}$-aminophosphonate was efficiently employed in this reaction. ${\alpha}$-Aminophosphonate of anisaldehyde subjected to Horner-Emmons type condensation with 5-bromo-2-methoxybenzaldehyde to yield the deoxybenzoin, which was further methylated and then underwent tandem demethylation-cyclodehydration to afford the benzofuran scaffold in excellent yield. Finally Suzuki coupling with propenyl boronic acid afforded eupomatenoid-6 with an overall yield of 56.8%.

• Archives of Pharmacal Research
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• v.22 no.1
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• pp.25-29
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• 1999

Psammaplin A, a natural bromotyrosine derivative from an associated form of two sponges (Poecillastra sp. and jaspis sp.) was found to possess the antimicrobial effect on the Gram-positive bacteria, especially on methicillin-resistant Staphylococcus aureus (MRSA). The minimal inhibitory concentration of psammaplin A against twenty one MRSAs ranged from 0.781 to 6.25 ${\mu}g/ml$, which that of ciprofloxacin was 0.391~3.125${\mu}g/ml$. Psammaplin A could not bind to penicillin binding protein, but inhibited the DNA synthesis and the DNA gyrase activity with the respective 50% (DNA synthesis) and 100% (DNA gyrase) inhibitory concentration 2.83 and 100 ${\mu}g/ml$. These results indicate that psammaplin A has a considerable antibacterial activity, although restricted to a somewhat narrow range of bacteria, probably by inhibiting DNA gyrase.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.553-558
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• 2001

A stereoselective synthesis of $1\beta-aminocarbapenems$ (11a-c) starting from-4-acetoxy-2-axetidinone derivative 4 is described. 4-Acetoxy-2-azetidinone derivative (4) was reacted with lithium enolate of benzophenone limine of glycine phenyl ester (5f) to give alkylated product (R)-6f in good yield with high diastereoselectivity. The alkylated procudt (R)-6f was transformed to thioesters (7a-c) by transesterification with thiols, Thioesters (7a-c) were converted to their oxalimides (8a-c), followed by the phosphite-mediated reductive cyclization to give carbapenems (9a-c). Removal of all protecting groups of carbapenems (9a-c) afforded $1\beta-aminocarbapenems$ (11a-c).

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.2097-2100
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• 2011