• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.738-743
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• 2013

Linoleic acid and its metabolites have various medicinal effects with carboxylic acid functional group. General carboxylic acid compounds are discovered as glucuronide metabolites by UGT glucuronosyl transferase at liver. Consequently, glucuronides of linoleic acid metabolites are expected as potent conjugated metabolite. A previous study reported two epoxide metabolites and two dihydroxy metabolites of linoleic acid. There are prepared their glucuronic acid conjugated compounds as potent linoleic acid metabolites.

• Journal of Korean Society of Forest Science
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• v.38 no.1
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• pp.55-59
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• 1978

알카리 리그닌의 착색구조(着色構造)를 확실(確實)히 하기 위(爲)하여 리그닌 모델 화합물(化合物)인 바니릴알콜을 질소하(窒素下)에 알카리로 처리(處理)하였다. 그림-1과 같이 ${\alpha}$-1 결합(結合)인 화합물(化合物) I., ${\alpha}$-1와 ${\alpha}$-5의 결합(結合) 구조(構造)인 화합물(化合物) II, III, IV와 ${\alpha}$-5결합(結合) 구조(構造)인 화합물(化合物) V를 단리(單離) 동정(同定)하였다. 이들 화합물(化合物)은 공기산화(空氣酸化) 및 알카리 처리(處理)에 의(依)해 착색(着色)되었다.

• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.362-373
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• 2016

In this study, ionic compound in the science textbooks developed under the 2009 revised national curriculum were analyzed in terms of the scientific concept and model description and the student understanding through the questionnaires. Analysis of textbooks was performed for science2 of middle school and chemistry I & II of high school. Questionnaire was carried out with 194 students including middle school 2nd grade and high school 1st-3rd grade. The results are as follows: First, as a result of analysis of textbooks, scientific concepts and models used to explain the ionic compound showed differences depending on the types of textbooks. In addition, scientific models were provided with or without explanation for the scientific concepts. Second, analysis of the questionnaire showed that students didn’t properly understood scientific concepts and models in the ion formation, stoichiometric ratio between ions.

• Applied Biological Chemistry
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• v.17 no.2
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• pp.125-137
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• 1974

The chemical structure of glycolipid of Selenomonas ruminantium cell wall was to be elucidated. The bacterial cells were treated in hot TCA and the glycolipid fractions were extracted by the solvent $CHCl_3\;:\;CH_3OH$ (1 : 3). The extracted glycolipids fraction was further separated by acetone extraction. The acetone soluble fraction was named as the spot A-compound. The acetone insoluble but ether soluble fraction was named as the spot B-compound. These two compounds were examined for elucidation of their chemical structure. The results were as follows: 1. The IR spectral analysis showed that O-acyl and N-acyl fatty acids were linked to glucosamine moiety in the spot A-compound. However in the spot B-compound in addition to O and N-acyl acids phosphorus was shown to be attached to glucosamine. 2. It was recognized by gas liquid chromatography that spot A compound contained beta-OH $C_{13:0}$ fatty acid in predominance in addition to the fatty acid with beta-OH $C_{9:0}$, whereas the spot B compound was composed of the predominant fatty acid of beta-OH $C_{13:0}$ with small amount of beta-OH $C_{9:0}$. 3. According to the paper chromatographic analysis of hydrazinolysis products of the spot A compound, a compound of a similar Rf value as the chitobiose was recognized, which indicated a structure of two molecules glucosamine condensed. The low Rf value of the hydrazinolysis product of the spot B-compound confirmed the presence of phosphorus attached to glucosamine. 4. The appearance of arabinose resulting from. ninhydrin decomposition of the acid hydrolyzate of the spot A compound indicated that the amino group is attached to $C_2$ of glucosamine. 5. The amount of glucosamine in the N-acetylated spot A compound decreased in half of the original content by the treatment. with $NaBH_4$, indicating that there are two molecules of glucosamines in the spot A compound. The presence of 1, 6-linkage between two molecules of glucosamine was suggested by the Morgan-Elson reaction and confirmed by the periodate decomposition test. 6. By the action of ${\beta}-N-acetyl$ glucosaminidase the N-acetylated spot A compound was completely decomposed into N-acetyl glucosamine, whereas the spot B compound was not. This indicated the spot A compound has a beta-linkage. 7. When phosphodiesterase or phosphomonoesterase acted on $^{32}P-labeled$ spot B compound, $^{32}P$ was not released by phosphodiesterase, but completely released by phosphomonoesterase. This indicated that one phosphorus is linked to glucosamine moiety. 8. The spot A compound is assumed to have the following chemical structure: That is glucosaminyl, ${\beta}-1$, 6-glucosamine to which O-acyl and N-acyl fatty acids are linked, of which the predominant fatty acid is beta-OH $C_{13:0}$ fatty acid in addition to beta-OH $C_{9:0}$ fatty acid 9. The spot B compound is likely to have the linkage of $glucosaminyl-{\beta}-1$, 6-glucosamine to which phosphorus is linked in monoester linkage. Furthermore both O-acyl and N-acyl fatty acids contained beta-OH $C_{13:0}$ fatty acid predominantly in addition to beta-OH $C_{9:0}$ fatty acid.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.739-750
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• 2012

The purpose of this study is to analyze the cognitive demands level of the description about 'pure substance and mixture compound', 'ionic compound', 'molecule' on the 'science2' textbooks by the 2007 revised curriculum. The three types of Curriculum Analysis Taxonomy have been used to analyze the cognitive demands level of those contents on the 6 kinds of 'science2' textbooks. The first, the cognitive demand level about 'pure substance and mixture compound' on many textbooks is a late concrete operational stage because of class inclusion and hierarchical classification. And the descriptions as 'pure substance is conserved even when mixed with other pure substance' is a early formal operational stage. The second, the cognitive demand level about 'ionic compound' and 'molecule' is a early formal operational stage, because of "Formal modeling is the indirect interpretation of reality by deductive comparison from a postulated system with its own rules" and "Atoms have a structure". The third, the terms as 'ionic bonding', 'ionic compound', 'chemical formula', 'covalent bonding', 'covalent compound', and 'molecular formula' have been used on many 'science2' textbooks. Those terms would be used later on 'chemistry I' and 'chemistry II' in senior high school but not even 'science3' and 'science'.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.54-63
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• 2017

유기 화학에서 Aromatic 화합물은 내부 전자의 비편재화로 인해 부가적인 에너지적 안정성을 얻는 화합물을 일컫는다. 이러한 화합물의 aromaticity를 판단하는 보편적인 기준으로는 Huckel's rule이 널리 알려져 있다. 그러나 Huckel's rule은 복잡한 화합물에서는 적용이 어려울 뿐 아니라 최근에는 Huckel's rule에서 벗어난 aromatic 화합물이 보고되고 있다. 따라서 본 연구에서는 Huckel's rule의 한계를 보완하고자 aromatic 화합물의 에너지적, 구조적, 자기적 성질을 계산화학적 방법으로 분석하고 이를 토대로 체계적인 기준을 제시하였다. 본 연구에서는 동일한 수의 탄소와 수소로 구성된 $C_nH_n$ 형태의 annulene 또는 annulene 라디칼과 이들의 이온을 계산 대상으로 설정하여 homodesmotic stabilization energy (HSE), C-C결합 길이, nucleus-independent chemical shift (NICS)를 산출해내기 위한 density functional theory (DFT) 계산을 수행하였다. 그 결과 aromatic 화합물은 공통적으로 0보다 큰 HSE 값을 가지며 C-C결합 길이가 비교적 일정하고 0보다 작은 NICS 값을 갖는 것을 확인할 수 있었다.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.147-150
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• 2015

Polynitrogen Compounds (PNC)는 질소만으로 이루어진 물질을 칭하며, 주로 질소간의 단일 결합과 이중결합으로 이루어져 있다. 질소 간 단일결합에너지 38.4kcal/mole에 비해 유난히 큰 229kcal/mole의 삼중결합 에너지 덕택에 PNC는 고에너지 물질로 큰 각광을 받고 있다. PNC는 합성과정이 큰 흡열반응으로 실험이 까다로워 이론적인 연구가 많이 진행되어왔다. 그 중에서 고리형태의 $N_5{^-}$가 안정할 것으로 예측되며, 실험적으로도 발견되었다. $N_5{^-}$를 안정화시키기 위해 많은 연구가 진행되었으며 그 중 하나가 금속과의 결합을 통한 화합물의 안정화이다. 본 연구에서는 $N_5{^-}$와 Cyclopentadienyl($C_5H_5{^-}$)이 전자구조나 기하학적 구조가 매우 유사함에 착안하여 이미 상대적으로 많은 합성이 보고되어 있는 $M(C_5H_5)_3$, $M(C_5H_5)_4$의 전이금속 M구조에 대하여 아직 발견되지 않은 $M(N_5)_3$, $M(N_5)_4$ 화합물의 구조와 열역학적 안정성을 알아보도록 한다. 본 연구에서 찾아진 $Zr(C_5H_5)_4$은 현재까지 실험적으로 보고된 $M(C_7H_7)(C_5H_5)$ 클러스터 구조에 비해 질소함유량이 약 67% 더 높다.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.123-127
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• 2002

DRAM용 capacitor의 차세대 전극물질 후보 중의 하나인 Ru 박막을 고밀도의 ECR 플라즈마를 이용하여 식각 특성 및 식각 메커니즘을 알아보고자 하였다. 식각시 Ru은 oxygen들과 결합을 하여 RuO2 화합물들을 생성하고 RuO2 화합물들은 다시 oxygen들과 결합을 함으로써 휘발성이 강한 RuOx 화합물들을 생성하였다. 하지만 이러한 식각이 이루어지기 위해서는 oxygen이온들에 의한 충돌이 필요하며, Cl과 F 가스들을 첨가가 의해 충돌 이온의 에너지가 증가되어 RuO2와 O radical들의 반응성을 향상시켰다. 이에 휘발성이 좋은 RuO4들의 형성속도를 증가시킴으로써 식각 속도를 향상시킬 수 있었다.

• Nuclear Engineering and Technology
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• v.10 no.1
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• pp.1-12
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• 1978

Concanavalin-A, lectin extracted from Korean native plant “Banha”(Pine-llia Termata) and their conjugation products with tyrosine and 5-iodo-6-aminouracil were labelled by radioactive iodiae-125, and these labelled compounds were subjected to a hemagglutination test in vitro. The labelling procedures were presented with respect to labelling yield and the trends on the conjugation reaction of lectin with various amino acids were discussed. The preliminary results on the hemagglutination tests against cancer tissues were presented and the potential clinical applications of these labelled compounds were discussed.

• Applied Chemistry for Engineering
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• v.2 no.1
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• pp.12-29
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• 1991

Stereoselective synthetic efforts for erythronolide A seco acid are reviewed from the first discovery of erythromycin A in 1952 up to the end of 1990. The synthetic strategies for construction of ten asymmetric centers embedded in an aglycone of erythramycin A have mostly been realized by the stereoselective preparation of the key fragments followed by coupling them. The synthetic methods employed for the key fragments can be classified into three categorie; a carbohydrate approach, a cyclic approach and an acyclic approach. The coupling has largely been reduced to practice by either aldol-type additions or Wittig olefinations of the key fragments.