• 한국응용과학기술학회지
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• 제22권1호
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• pp.9-14
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• 2005

Competitive solvent extraction of alkaline earth metal cations from water into organic solvent containing the carboxylic acid crown ether and analogous crown ether phosphonic acid monoethyl esters were investigated. sym-(n-Decyldibenzo)-16-crown-5xyacetic acid $\underline{1}$ and monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid $\underline{3}$ are structurally identical except for the ionizable groups. Both of them provide similar extraction behavior in terms of efficiency and selectivity, but monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid $\underline{3}$ showed higher alkaline earth metals loadings at acidic or neutral media. Monoethylsym-(n-octyldibenzo)-16-rown-5-oxymethylphosphonic acid $\underline{2}$ showed better selectivity and alkaline earth metals loading than did the analogous sym-(n-octyldibenzo)-16-crown-5-oxymethyldiphosphonic acid $\underline{6}$.

• 약학회지
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• 제37권3호
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• pp.295-305
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• 1993

In order to develop oral cephalosporin having a new substituent at 3 position, the synthesis of cephalosporins modified at C-3 and the effect of the substituents on the oral absorption is studied. 7-[(Z)-2-(2-Aminothiazole- 4-yl)-2-methoxyiminoacetamidol-3-[4-(2-pyridyl )piperazinyl] thiocarbonylthiomethyl-3-cephem-4-carboxylic acid (CEN1) and 7-[(Z)-2-(2-aminothiazole-4-yl)-2-methoxyiminoacetamido]-3-[4-(2-pyrimid yl)piperazinylthiocarbonylthiomethyl-3-cephem-4-carboxylic acid (CEN2) were synthesized from 4-(2-piridyl)piperazinyl dithiocarbamate potassium salt or 4-(2-pirimidyl)piperazinyl dithiocarbamate potassium salt and cefotaxime. Also pivaloyloxymethyl esters of CEN1 and CEN2, pivaloyloxymethyl 7-[(Z)-2-(2-aminothiazole-4-yl)-2-methoxyiminoacetamido]-3-[4-(2-pyridyl )piperazinyllthiocarbonylthiomethyl-3-cephem-4-carboxylate (CENIP) and pivaloyloxymethyl 7-[(Z)-2-(2-aminothiazole-4-yl)-2-methoxyiminoacetamidol-3- [4-(2-pyrimid yl)piperazinyllthiocarbonylthiomethyl-3-cephem-4-carboxylate (CEN2P) were synthesized. The in vitro activities of two new oral cephalosporins, CEN1 and CEN2, were compared with the in vitro activities of cefaclor and cefotaxime against a variety of bacterial species. CEN2 has a broad antibacterial spectrum covering Gram-positive and Gram-negative bacteria, similar to that exhibited by CEN1 and cefotaxime. CEN1 and CEN2 were more active in vitro than cefaclor against Streptococcus pyogenes, Klebsiella aerogenes and Enterobacter cloacae.

• Bulletin of the Korean Chemical Society
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• 제25권3호
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• pp.407-409
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• 2004

• 대한화학회지
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• 제55권6호
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• pp.1012-1017
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• 2011

Novel surfactants have been synthesized by catalytic chloropropoxylation reaction of carboxylic acid fractions of sunflower, olive, cottonseed, soya-bean, castor and corn oils with 2-(chloromethyl)oxirane. Colloidal-chemical parameters as well as petroleum-collecting and petroleum-dispersing capacities of the synthesized chloropropoxylate esters having heterochain of various lengths have been determined. Influence of carboxylic acid fractions composition and length of chloroxypropylene chain on petroleum-collecting and dispersing capacities has been revealed.

• Bulletin of the Korean Chemical Society
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• 제8권4호
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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.

• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.501-505
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• 2004

Esterification of aliphatic or aromatic carboxylic acids with alcohols using 2-(4-nitrobenzenesulfonyl)-4,5-dichloropyridazin-3(2H)-one (3) in the presence of base in organic solvents gave the corresponding esters in excellent yields

• Preventive Nutrition and Food Science
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• 제13권2호
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• pp.128-133
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• 2008

The volatile flavor components were isolated from the roots of Saussurea lappa C.B. Clarke produced in Korea and China by the hydro distillation, and were analyzed by gas chromatography-mass spectrometry (GC/MS). 63 aroma compounds representing 87.47% of the total peak area were tentatively identified, including 13 alcohols (22.56%), 26 hydrocarbons (21.78%), 4 aldehydes (21.24%), 11 ketones (18.04%), 1 oxide (0.52%), 3 esters (0.16%), 1 carboxylic acid (0.02%) and 4 miscellaneous components (3.15%). 46 volatile flavor components of imported S. lappa C.B. Clarke constituted 65.69% of the total volatile composition were tentatively characterized, consisting of 1 aldehyde (23.32%), 24 hydrocarbons (16.69%), 10 ketones (15.84%), 7 alcohols (8.92%), 1 oxide (0.83%), 2 esters (0.07%) and 1 acid (0.02%). The predominant components of both essential oils were (7Z,10Z,13Z)-7,10,13-hexadecatrienal and dehydrocostuslactone.

• 대한화학회지
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• 제16권3호
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• pp.178-188
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• 1972

Diethyl itaconate was found to react tetrafluoroethylene, trifluorochloroethylene, and 1,1-difluoro-2,2-dichloroethylene quite rendily at $180^{\circ}C$ to form 1-carboxy-2,2,3,3,-tetrahalo-cyclobutane ethanoic acid derivatives ${C{\underline{X_2-CF_2-CH_2-}}C-(COOEt)-CH_2COOEt$, where X is Cl or F). Diethylcitraconate failed to yeild any cycloaddition products. The Physical and Chemical properties of the above esters and their dericatives are characterized and compared with other similar ring compounds.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.9-10
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• 2003

• Archives of Pharmacal Research
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• 제15권3호
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• pp.204-207
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• 1992

Glycylglycine, alanylalanine and alanylglycine were synthesized, their free carboxylic and amino groups were converted to methyl esters of N-acetylglycyglycine, N-acetylalanylglycine and N-acetylalanylalanine. The synthesized compounds were evaluated for antiepileptic activity, plasmaprotein binding, $TD_{50}$ and potentiating effect of phenobarbitone sodium.