• Journal of Microbiology and Biotechnology
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• 제8권5호
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• pp.540-542
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• 1998

Five microorganisms capable of degrading an aromatic medium-chain-length polyhydroxyalkanoate ($PHA_{MCL}$), poly(3-hydroxy-5-phenylvalerate) (PHPV), were isolated from wastewater-treatment sludge. Among the isolates, JS02 showed degrading activity consistantly during several transfers. The isolate JS02 could hydrolyze another aromatic MCL copolyester, poly(3-hydroxy-5-phenoxyvalerate-co-3-hydroxy-7-phenoxyheptanoate), ［P(5POHV-co-7POHH)］, and other short-chain-length PHAs ($PHA_{SCL}) such as poly(3-hydroxybutyrate) ［P3(HB)］, poly(3-hydroxybutyrate-co-4-hydroxybutyrate) ［P(3 HB-co-4 HB)］, and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) ［P(3HB-co-3HV)］ with relatively low activity. The culture supernatant of JS02 showed hydrolyzing activity for the p-nitrophenyl esters of fatty acids.

• Bulletin of the Korean Chemical Society
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• 제24권12호
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• pp.1819-1826
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• 2003

In connection with the studies for developing new enzymes that could be useful in organic synthesis, practical preparation of racemic and enantiopure forms of ${\gamma}$-hydroxy-${\alpha}$-keto acids has been successfully achieved. For racemic form of ${\gamma}$-hydroxy-${\alpha}$-keto acids, indium-mediated allylation of aldehydes with 2-(bromomethyl)acrylic acid has been employed as a key step. Oxidative cleavage of the thus formed 2-methylenebutyrolactones provided the desired ${\alpha}$-ketobutyrolactones. Enzymatic resolution of the ${\gamma}$-hydroxy-${\alpha}$-methylene esters provided the desired${\gamma}$-hydroxy-${\alpha}$-methylene acids which were successfully converted to ${\gamma}$-hydroxy-${\alpha}$-ketobutyrolactones in optically pure forms.

• Archives of Pharmacal Research
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• 제6권1호
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• pp.1-6
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• 1983

The reaction of ethylenecarbonate (I) with bromine was carried out in the presence of benzolperoxide as radical initiator. The following several different esters being ring opened were obtained; bromoacetyl-bromoformate, (1-hyroxy, 1, 2-dibromo)-ethyl bromoformate, (1-hydroxy, 1, 2, 2'-tribromo)diethylacarbonate, 2-bromoethyl-tribromoacetate, (1-acetoxy, 1'-bromomethyl)-bromomalo nate, 2-bromoethyl-bromoacetoxy-tribromoacetate.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.207-212
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• 2004

In this study, we attempted to prepare compounds with heterocyclic replacements for metabolically unstable esters of benzopyranyl indole-2-carboxylic esters, which showed good in vitro and in vivo cardioprotective efficacies possibly through the opening of mitochondrial ATP-sensitive potassium channel ($K_{ATP}$). Initially, we tried to construct indolin-2-yl-heterocycles using unprotected indoline-2-carboxylic acid, but the cyclization was proceeded with oxidation of the indoline ring to the indole, which didn't react with benzopyranyl epoxide. Thus we introduced N-Boc group to deplete the electron density of the indoline ring. We successfully prepared various indolin-2-yl-heterocycles by the cyclization of the building blocks including carboxamide, ${\beta}$-hydroxy amide, hydrazide, nitrile starting from N-Boc-indoline-2-carboxylic acid.

• Bulletin of the Korean Chemical Society
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• 제8권3호
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• pp.162-165
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• 1987

The reduction rate of borohydride exchange resin (BER) was greatly enhanced in the presence of lithium salts. Thus 2-heptanone was reduced completely with BER-LiCl in 1 h at room temperature. However, no reduction was observed with BER alone under the same conditions. With this system, organic compounds containing various fuctional groups were examined in ethanol at room temperature. This study revealed that BER-LiCl system exhibits an excellent chemoselectivity for carbonyl group in the presence of other functional groups. Keto esters and epoxy ketones were reduced with BER-LiCl to give the corresponding hydroxy esters and epoxy alcohols with excellent yields. Selective reductions of carbonyl groups were also possible in the presence of other organic compounds containing functional groups such as 1-idooctane, 1-bromooctane, caproamide, hexanenitrile, nitrobenzene, n-butyl disulfide, dimethyl sulfoxide and 1-dodecene.

• Journal of Pharmaceutical Investigation
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• 제14권2호
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• pp.70-75
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• 1984

The contents of organic acid esters in Angelicae gigantis radix were studied using GC-MS. The results revealed that the concentration of propyl p-hydroxy benzoate was 3.0ppm in the head part, 10.5ppm in the main body and 3. 5ppm in the lateral part.

• Bulletin of the Korean Chemical Society
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• 제29권4호
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• pp.859-862
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• 2008

• 대한화학회지
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• 제13권4호
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• pp.325-332
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• 1969

An attempt has been made to investigate the nature of the characteristic darkening reaction occurring in the rice bran oil during the storage. Several pigments were separated by using column and thin layer chromatography of the pigments was made in the light of the knowledge of absorption spectral behavior. The presence of trace amount of iron and phytosteryl esters of ferulic acid (3-methoxy-4-hydroxy-cinnamic acid) was found to be responsible for the development of the characteristic color in rice bran oil. The model reactions with the ferulate, iron and fatty acids could be suggested the mechanism.

• Bulletin of the Korean Chemical Society
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• 제30권5호
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• pp.1211-1214
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• 2009

• 한국식품과학회지
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• 제30권2호
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• pp.299-305
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• 1998

양조, 사과, 현미, 감식초의 휘발성 성분을 분석하고 식초들 간의 관능적 차이를 냄새관점에서 평가하였다. 식초의 휘발성 성분으로 30개의 화합물을 동정할 수 있었으며 9 carbonyl compounds, 12 esters, 6 alcohols 그리고 3 acids로 분류되었다. 3-Hydroxy-2-butanone은 일부 식초에서만 검출되고 감 식초는 다른 식초에 비해 다양한 alcohols을 함유하는 것이 특징이었다. 3-Methyl-1-butanol은 양조 식초에서 전혀 확인되지 않았고 대부분의 사과, 현미, 감식초에서 검출되었다. 감식초는 기타취의 강도가 강하여 기호도가 낮고(p<0.05) 전체적인 향 만족도에서 사과, 양조, 현미 식초에 비해 유의적으로(p<0.01) 열세였다.