• Bulletin of the Korean Chemical Society
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• v.11 no.6
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• pp.538-542
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• 1990

New aminothiazolyl cephalosporins with alkoxyiminomethyl(2-aminothiazol-4-yl)acetyl substituents at 7-position of cephems were synthesized starting from (2-aminothiazol-4-yl)acetate via one carbon homologation followed by acylation with 7-aminoceph-3-em-4-carboxylic acid derivatives. These new aminothiazolyl cephalosporins exhibit promising in vitro activities against various strains including Gram positive bacteria.

• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.264-269
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• 1987

Various carbocation-mediated cyclizations to tricyclene structure (basically, tricyclo $[2,2,1,0^{2,6}]$ heptane skeleton) were carried out, starting from protonated species of either 3-methyl-2,5-norbornadiene-2-carboxylic acid (10) or 3-methylene-5-norbornene-2-carboxylic acids (18 and 19). The resulting products were individually converted to ${\pi}$-iodotricyclene (35), a pivotal intermediate in almost all syntheses of tricyclene terpenes.

• YAKHAK HOEJI
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• v.38 no.6
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• pp.664-672
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• 1994

Eighteen new hybrid bivalent ligand quinolones that contain two different type of pharmacophores in a single molecule were prepared and evaluated for in viかo antibacterial activity. Hybrid bivalent ligands p-nitrobenzyloxycarbonyl quinolones were prepared by the treatment of active esters of succinyl fluoroquinolones with 1,7-disubstituted fluoroquinolone carboxylic acids in DMF. Eighteen final quinolone carboxylic acids were obtained by the reduction of compounds $25{\sim}42$ with hydrogen in the presence of 10% Pd-C. Among these derivatives, compound[56] showed the most potent antibacterial activity against a wide range of microoranisms.

• Journal of the Korean Chemical Society
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• v.16 no.6
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• pp.369-372
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• 1972

The dissociation constants of dibasic carboxylic acids $(HOOC(CH_2)_nCOOH$, n = 0~4] in methanol, N, N-dimethylformamide and acetonitrile have been determined by the potentiometric method with a glass electrode. The difference between over-all dissociation constants in each other solvent is found to be of the same order of magnitude, and the $K_1/K_2$ ratios in aprotic dimethylformamide and acetonitrile are much greater than those in protic methanol and water.

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1583-1587
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• 2009

The four dentate $N_2O_2$ Schiff base ligand of bis(2-hydroxyacetophenone)-1,2-propanediimine (BHAPN) and its manganese (III) complex were synthesized and identified by microanalysis, spectral data ($^1H$ NMR, MS, FT-IR and UV-Visible) and molar conductivity measurement. The mild and efficient homogeneous oxidative decarboxylation of some carboxylic acids by catalytic amount of this manganese (III) complex, using tetrabutylamonium periodate as a mild oxidant in chloroform at room temperature is reported. The catalyst used in this study showed good activity for the decarboxylation of the titled compounds.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2899-2904
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• 2009

Esterification is an important class of reactions in the preparation of perfumery and flavor chemicals, wherein homogeneous, solid acidic, and superacidic catalysts are normally used. Now, an efficient and selective protocol for protection of various functionalized alcohols employing carboxylic acids as protecting agents is realized through the catalytic mediation of simple heteropolyoxometallates. In this methodology, water is the only by-product and notably the aspect of effluent treatments does not arise. The advantages include the operational simplicity, recycle ability of the catalyst and mild reaction conditions. The present catalytic system may be a potential candidate not only for laboratory practice but also for commercial applications and offers an environmentally safer alternative to the existing processes.

• YAKHAK HOEJI
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• v.35 no.5
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• pp.353-359
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• 1991

Treatment of 1-ethyl-6-fluoro-1, 4-dihydro-4-oxo-7-(l-piperazinyl)-I, 8- naphthyridine-3-ca rboxylic acid (Enoxacin) with alkyl(or aryl) isothiocyanates which obtained from alkyl(or aryl) amines afforded six 1-ethyl-6-fluoro-1, 4-dihydro-4-oxo-7-(1-alkylthiocarbamylpiperazinyl)-1, 8- naphthyridine-3-carboxylic acids and five 1-ethyl-6-fluoro-1, 4-dihydro-4-oxo-7-(l-arylthiocarbamyl piperazinyl)-1, 8-naphthyridine-3-carboxylic acids. The compounds synthesized were evaluated for their antimicrobial activities, in vitro, against Escherichia coli 6-PE-4, Bacillus subtilis 74-51, Proteus vulgaris 78645, Klebsiella pneumoniae JYA-78314, Staphylococcus aureus 79110 and Pseudomonas aeruginosa 8765-1 P$_{2}$.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.2034-2040
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• 2007

Efficient catalytic systems, where Ni or Pd is introduced in a supporting material of nanoporous carbon, have been developed for a liquid-phase hydrogenation of carboxylic acids and ketones at room temperature. It has been found that the catalysts reliably show high activities and selectivities for the hydrogenation to alcohols even in acidic conditions, and the catalytic activities depend on the preparative method of catalysts, the hydrogen pressure, the agitation rate, and the catalytic species. The hydrogenation of carboxylic acids and ketones clearly shows that the reaction rate is affected by the electronic and the steric effects, and a plausible reaction mechanism using metal hydrides as catalytic species is proposed.

• Journal of Life Science
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• v.13 no.6
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• pp.943-949
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• 2003

New quinolone derivatives of 7-(cis- or trans-3-amino-4-mehtylthiomethylpyrrolidinyl) quinolone-3-carboxylic acids were synthesized by condensation of 7-halo substituted quinolone-3-carboxylic acids with cis- or trans-3-amino-4-mehtylthiomethylpyrrolidine. Some of these compounds showed broad spectra of antibacterial activities against Gram-positive and Gram-negative organisms except Pseudomonas aeruginosa, and exhibited much stronger activity against MRSA.

• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.313-318
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• 1987

The approximate rate and stoichiometry of the reaction of excess Thexylbromoborane-methyl sulfide, $ThxBHBr{\cdot}SMe_2,$ with selected organic compounds containing representative functional groups under standardized conditions (methylene chloride, $0^{\circ}C)$ were studied in order to characterize the reducing characteristics of the reagent for selective reductions. The selectivity of the reagent was also compared to the selectivity of thexylchloroborane-methyl sulfide. Thexylbromoborane appears to be a much milder and hence more selective reducing agent than thexylchloroborane. The reagent tolerates many organic functionalities. Thus, the reagent shows very little reactivity or no reactivity toward acid chlorides, esters, epoxides, amides, nitro compounds including simple olefins. However, this reagent can reduce aldehydes, ketones, carboxylic acids, nitriles, and sulfoxides. Especially the reagent reduces carboxylic acids including ${\alpha},{\beta}$ -unsaturated ones and nitriles to the corresponding aldehydes. In addition to that, thexylbromoborane shows good stereoselectivity toward cyclic ketones, much better than the chloro-derivative.