• Journal of Environmental Science International
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• v.7 no.1
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• pp.62-66
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• 1998

Toxic Mastoparan B(MP-B) which is purified from the venom of the hornet Vespa basalis is a cationic amphlphilic tetradecapeptide. MP-B and Its Ala-substituted analogues were synthesized by solld phase method and the toxic peptide-membrane interactions were examined by circular dichroism(CD) spectra, fluorescence spectra, and leakage abilities in phospholipid membranes. In the presence of phospholipid vesicles, synthetic MP-B and its analogues formed amphiphilic -helical structures, but in the buffer soletion, those exhibited random coil conformation as measured by CD. Fluorescence spectra of MP-B and its analogues which indicated the binding affinity of peptide on phospholipid vesicles showed that the replacement of Lys at position 2 and 11 with Ala caused a remarkable effect in the blue shalt and that at position 2, in the leakage ability of the peptide.

• Journal of Pharmaceutical Investigation
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• v.36 no.2
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• pp.103-107
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• 2006

In order to develop hydroquinone analogues for topical delivery, a structure-activity relationship study has been performed. A series of 2-substituted hydroquinones were tested for their ability to inhibit mushroom tyrosinase, alter melanin release and exert cytotoxicity in B6-F10 melanocytes. The electronic property of the 2-substituents did not affect the tyrosinase inhibition nor melanocyte toxicity. However, lipophilicity did affect to some degree the tyrosinase inhibition. The discrepancy in the structure-activity relationship may be due to the poor aqueous solubility of select analogues. Compounds with steric bulk at the 2-position seems to be less soluble, not enabling the analogue to interact effectively with the tyrosinase enzyme. Among the analogues tested, 2-isopropyl hydroquinone seems to be the most promising candidate for topical delivery, being the least toxic analogue with moderate melanin release inhibition.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3621-3628
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• 2013

Novel 5'-deoxythreosyl purine phosphonic acid analogues containing a 2'-electropositive moiety such as fluorine atom, were designed and synthesized from commercially available 1,3-dihydroxy acetone. Condensation successfully proceeded from a glycosyl donor 6 under Vorbr$\ddot{u}$ggen conditions and cross-metathesis gave the desired phosphonate analogues 7a, 7b, 17a and 17b. The synthesized nucleoside phosphonic acid analogues 13, 16, 23, 26, 28 were subjected to antiviral screening against HIV-1. The bis(SATE) adenine analogue 28 exhibited significant in vitro activities against HIV-1.

• Archives of Pharmacal Research
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• v.13 no.1
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• pp.43-50
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• 1990

Conformational free energy calculations using an empirical potential function (ECEPP/2) and hydration shell model were carried out on the four-4-aminodiphenyl sulfone analogues of 4, 4'-diamino-2' methyldiphenyl sulfone, 4, 2', 4-triaminodiphenyl sulfone, 4, 4'-diaminodiphenyl sulfone, and 4-aminodiphenyl sulfone as antibacterial agents on Mycobacterium lufu. The conformational energy was minimized from starting conformations which included possible combinations of torsion angles in the molecule. The conformational entropy change of each conformation was computed using a harmonic approximation. To understand the hydration effect on the conformation of the molecule in aqueous solution, the contributions of water-accessible volume and the hydration free energy of each group or atom in the lowest-free-energy conformation was calculated and compared each other. From comparison of the computed lowest-free-energy conformations of four analogues with their antibacterial activities, it is known that the conformation and the hydrophobicity of sulfonyl group and its adjacent carbon atom in each compound are the essential factors to show the strong antibacterial activity.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.273-277
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• 2005

Dynamic resolution of $\alpha$-bromo tertiary acetamides in asymmetric nucleophilic substitution reaction is described. Intermolecular substitution of $\alpha$-bromo tertiary acetamides with dibenzylamine in the presence of TBAI and $Et_3N$ gave the dipeptide analogues 7-10 with high stereoselectivities up to 90 : 10 dr. Also, cyclic dipeptide analogues 20-29 were produced by the intramolecular nucleophilic cyclization of $\alpha$-bromo tertiary acetamides with low stereoselectivities in 84-42% yields.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.483-488
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• 2011

Present work comprises of synthesis various analogues of ciprofloxacin by introducing new functionality at carboxylic group position via ester aminolysis reaction. For this purpose the carboxylic group at C-3 was esterified and later subjected to nucleophilic attack at the carbonyl carbon by various aromatic amines. Structure of the analogues was confirmed by different techniques i.e. IR, $^1H$ NMR and mass spectrometry. The antibacterial activity of the derivatives was also assessed with the parent against a series of Gram-positive and Gram-negative bacteria. The synthesized compounds showed diverse antimicrobial profile among which most compounds possessed a comparable or better activity in comparison to the ciprofloxacin. Additionally unlike ciprofloxacin, some of the derivatives were also found to show antifungal activity.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4309-4315
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• 2011

For synthesis of benzastatin E, F and G analogues, the indole-2-carbaldehydes with or without substituents at C-5 position were prepared as key intermediates. Several synthetic attempts to achieve benzastatin E-G analogues were suggested using the indole-2-carbaldehyde intermediates.

• Journal of the Korean Chemical Society
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• v.58 no.6
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• pp.569-574
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• 2014

The synthesis of O-desmethylangolensin (O-DMA) analogues from methoxy-substituted benzoic acids was described. Treatment of methoxy-substituted benzoic acids with 2 equiv of ethyllithium afforded methoxypropiophenones, which were subsequently transformed to ethyl 2-(methoxyphenyl)propionates via 1,2-rearrangement of the methoxyphenyl group using $Pb(OAc)_4/HClO_4$ in triethyl orthoformate. After hydrolysis with KOH, the 2-(methoxyphenyl)propionic acids were reacted with di-2-pyridyl carbonate to afford 2-pyridyl 2-(methoxyphenyl)propionates, which were acylated with methoxy-substituted phenylmagnesium bromides to give methoxy-${\alpha}$-methyldesoxybenzoins. The methoxy groups of these compounds were selectively or fully demethylated using boron tribromide to give diverse O-DMA analogues in high yields.

• Archives of Pharmacal Research
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• v.21 no.2
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• pp.157-163
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• 1998

Several aniline mustard analogues were obtained by introducing N,N-bis(2-chloroethyl)amino moiety to phenyl ring of A10 analogues in order to increase reactivity of A10 analogs and selectivity into DNA. The in vitro antitumor activity of synthesized compounds was evaluated using five different solid tumor cell lines by SRB method. Aniline mustard analogues exhibited more potent antitumor activity than A10 analogs. Especially, m-aniline mustard of benzoyl analogue displayed remarkable antitumor activity.

• Archives of Pharmacal Research
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• v.26 no.4
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• pp.253-257
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• 2003

Resveratrol analogs were newly synthesized and evaluated for cytotoxicity in cultured human lung and colon cancer cells. 3,5,4-Trimethoxy-trans-stilbene and 3,5,2',4'-tetramethoxy-trans-stilbene were found to be more potent rather than resveratrol. 3,4,5-Trimethoxy-4'-bromo-cis-stilbene was the most active among the test compounds.