• 대한화학회지
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• 제38권7호
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• pp.485-495
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• 1994

$[M(NO)_2Cl_2]_n(M = Mo, W)$을 출발물질로 사용하여 3단계 합성과정을 거쳐 $[Cl(dppp)(NO)_2M({\mu}-pyz)M'(NO)_2(dppp)Cl][ClO_4]_2$와 $[Cl(phen)(NO)_2M({\mu}-pyz)M'(NO)_2(dppp)Cl][ClO_4]_2$(M,M'= Mo or W; phen = 1,10-phenanthroline; dppp = 1,3-bis(diphenylphosphino)propane; pyz = 1,4-pyrazine) 형의 새로운 대칭 및 비대칭 이핵 착물을 합성하였다. 최종 생성물은 실리카겔 칼럼($2{\times}20$ cm)을 통해 아세톤으로 용리시켜 분리하였다. 합성한 착물은 원소분석과 적외선, 핵사기 공명 및 전자 흡수스펙트럼 등을 이용해서 그 특성을 조사하였다. 적외선 스펙트럼은 모든 착물이 팔면체 구조로서 두 개의 NO기가 cis 위치로 배위되어 있음을 나타냈으며, $^1H$ 및 $^{13}C$ 핵자기 공명 스펙트럼은 이들 착물이 pyz가 다리결합하고 있는 이핵 착물임을 나타내었다.

• 한국식품과학회지
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• 제30권4호
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• pp.739-744
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• 1998

볶음장치(로타리킬른)를 사용하여 참깨볶음온도 $225{\pm}2^{\circ}C$, 볶음시간 15분으로 볶아서 나온 참깨를 착유하여 얻은 기름을 1차압착유, 1차착유하고 남은 참깨박을 재착유하여 얻은 기름을 2차압착유, 1차압착유와 2차압착유를 혼합해서 여과한 참기름을 1차여과유, 1차여과유의 침전물을 제거하기 위해서 정치시켜서 얻은 정치유, 정치유를 여과해서 얻은 참기름을 2차여과유로 구분하여 이들의 공정에 따른 참기름 향의 변화를 실험하였다. 전체향기성분량은 1차압착유 536.3 ppm, 2차압착유 266.8 ppm, 1차여과유 472.2 ppm, 정치유 472.4 ppm, 2차여과유 443.0 ppm으로 가공공정이 진행됨에 따라 점차 감소하였으며, 특히 1차압착하고 남은 참깨박을 재착유할 경우 2차압착유에는 약 50%의 향기성분만이 잔존하여 향성분의 손실이 크게 증가하였다. 특히 관능적으로 중요한 top note감소(초기함량치 70.67% 감소)가 현저함을 알수 있었으며, 그 중에서도 pyrazines의 손실이 초기함량의 66.9%로 가장 현저하였다.

• Archives of Pharmacal Research
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• 제22권2호
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• pp.99-107
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• 1999

A series of organosulfur compounds were synthesized with the aim of developing chemopreventive compounds active against hepatotoxicity and chemical carcinogesis. 2-(Allylthio) prazine (2-AP) was effective in inhibiting cytochrome P450 2E1-mediated catalytic activities and protein expression, and in inducing microsomal epoxide hydrolase and major glutathione S-transferases. 2-AP reduced the hepatotoxicity caused by toxicant sand elevated cellular GSH content. Development of skin tumors, pulmonary adenoma and aberrant crypt foci in colon by various chemical carcinogens was inhibited by 2-AP pretreatment. Anticarcinogenic effects of 2-AP at the stage of initiation of tumors were also observed in the aflatoxin B1 ($AFB_1$)-induced three-step medium-term hepatocarcinogenesis model. Reduction of $AFB_1$-DNA adduct by 2-AP appeared to result from the decreased formation of $AFB_1$-8,9-epoxide via suppression of cytochrome P450, while induction of GST 2-AP increases the excretion of glutathione-conjugated $AFB_1$ . 2-AP was a radioprotective agent effective against the lethal dose of total body irradiation and reduced radiation-induced injury in association with the elevation of detoxifying gene expression. 2-AP produces reactive oxygen species in vivo, which is not mediated with the thiol-dependent production of oxidants and that NF-KB activation is not involved in the induction of the detoxifying enzymes. the mechanism of chemoprotection by 2-AP may involve inhibition of the P450-mediated metabolic activation of chemical carcinogens and enhancement of electrophilic detoxification through induction of phase II detoxification enzymes which would facilitate the clearance of activated metabolites through conjugation reaction.

• 한국식생활문화학회지
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• 제22권6호
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• pp.808-812
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• 2007

해바라기박을 이용하여 직화법과 autoclaving법에 의하여 2종의 향미유를 제조하고 이의 특성을 살펴보았다. 직화법으로 얻은 원액의 색상, 향미 등이 상대적으로 autoclaving법으로 얻은 원액에 비하여 강하였다. 대조군으로 사용한 참기름에 비하며 향미유의 향미는 낮은 것으로 확인 되었으나 산가는 0.452, 0.463으로 참기름의 1.987보다 월등히 낮은 것으로 측정되었고 Lovibond color는 3종의 시료유에서 거의 유사하게 나타났다. 이들 향미유와 대조군으로 직접 제조한 참기름을 대상으로 정유성분의 휘발성 향기성분조성 및 함량을 측정해 보았다. 그 결과 총 휘발성 성분 함량은 참기름이 1,300.6 ppm, 직화법으로 제조한 향미유(A type)가 697.8 ppm, autoclaving법으로 제조한 향미유(B type)는 648.2 ppm으로 참기름 의 약 53.65% 및 49.84% 수준의 휘발성 성분을 함유한 것으로 확인되었다. 주요 휘발성 성분은 2-butanone, hexanal, methyl pyrazine 등이었으며, 참기름은 pyrazine류가 전체의 50% 이상을 차지하였으나 향미유에서는 이와 같은 특정성분에 의존하기 보다는 전체적으로 분산되는 경향을 나타내었다.

• 한국연초학회지
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• 제19권2호
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• pp.145-150
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• 1997

Nonvolatile polyhydroxyalkylpyrazines(PHAPs) are known to degrade volatile pyrazine compounds having positive aroma and sensory attributes during cigarette smoking. In this paper, the content of PHAPs in burley tobacco leaves toasted to different levels as temperature and time study were determined by high performance liquid chromatography, and was also investigated effects of added sugars, sucrose, glucose or fructose, on the generation of PHAPs during toasting. The addition of glucose or fructose as casing sauce in burley tobacco leaves resulted in significant increases, especially 2,6-deoxyfructosaBine from glucose added leaves and 2,5-deoxyfructosazint from fructose added leaves, in generation of PHAPs during toasting, while control and sucrose added leaves did not observed in generation of PHAPS. Formation rates of PHAPs in glucose or fructose added tobacco leaves, but not sucrose, showed a strong dependence on both toasting temperature and time.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.545-548
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• 2008

We report the synthesis of blue emitting materials with a new core structure containing indenopyrazine. Non-doped device using one of these materials as a blue emitter was found to exhibit high external quantumn efficiency of 4.6% and excellent color purity of (0.154, 0.078) as well as narrow emission band of 47nm FWHM.

• Food Science and Biotechnology
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• 제18권6호
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• pp.1495-1499
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• 2009

The volatiles formed from the reactions of L-ascorbic acid with L-alanine at 5 different pH (5, 6, 7, 8, or 9) and $140{\pm}2^{\circ}C$ for 2 hr was performed using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis were identified to be 25 different kinds. The reaction between L-ascorbic acid and L-alanine led mainly to the formation of pyrazines. Many of these were alkylpyrazines, such as 3-ethyl-2,5-dimethylpyrazine, 2,5-dimethylpyrazine, 2-ethyl-5-methylpyrazine, 3,5-diethyl-2-methylpyrazine, methylpyrazine, 2-ethyl-6-methylpyrazine, and 2,3-diethyl-5-methylpyrazine, other compounds identified were furans, phenols, benzoquinones, 2,4,6-trimethylpyridine, and 2-methylbenzoxazole. The studies showed that furans, such as furfural and benzofuran were formed mainly at acidic pH. In contrast, higher pH values could promote the production of pyrazines.

• Archives of Pharmacal Research
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• 제23권2호
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• pp.99-103
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• 2000

Acid and base catalyzed intramolecular cyclizations of N-benzoylthioureidoacetal, contain-ing four functional groups adjacent to thiourea such as benzocarbamoyl, acetal, thioure and amide, were investigated. The condensation reaction of N-benzoyl thiocarbamoylgly-cine amide in the presence of 10% aqueous NaOH provided 1-(2,2-dimethoxy)ethyl-imi- dazolidine-2-thione exclusively. In the presence of pyridine, it was transformed to 2- thiohydantoin. N-Benzoyl thiocarbamoyl glycine amide was completely transformed to an iminothiazolidine exclusively in the presence of Lewis acid such as borontrifluoride ether-ate or trimethylsilyl iodide. 1-(2,2-Dimethoxy)ethyl-imidazolidine-2-thione was transformed to imidazole[2,1-b]thiazole and pyrazino[5,1-a]imidazole in the presence of $BF_3$.$ET_2$O and formic acid, respectively.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1874-1876
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• 2004

Quantitative structure activity relationship has been probed for spirosuccinimide-fused tetrahydropyrrolo[1,2-a]pyrazine-1,3-dione derivatives acting as aldose reductase inhibitors. While the spirosuccinimide compounds contain a chiral center, the aldose reductase inhibition assay was performed with racemic mixtures in the published work. As the physicochemical descriptors of the QSAR analysis must be evaluated for a definite molecular structure, we devise a new 'racemic' descriptor as the arithmetic mean of the (R)-enantiomer descriptor and the (S)-enantiomer descriptor. The resultant QSAR model derived from the racemic descriptors outperforms the original QSAR models, closely reproducing the observed activity of optically pure enantiomers as well as racemic mixtures.

• Food Science and Biotechnology
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• 제18권3호
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• pp.700-705
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• 2009

In this study, the volatile compounds in 9 commercial fermented soybean pastes were extracted and analyzed by headspace-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS), respectively. A total of 63 volatile components, including 21 esters, 7 alcohols, 7 acids, 8 pyrazines, 5 volatile phenols, 3 ketones, 6 aldehydes, and 6 miscellaneous compounds, were identified. Esters, acids, and pyrazines were the largest groups among the quantified volatiles. About 50% of the total quantified volatile material was contributed by 5 compounds in 9 soybean paste samples; ethyl hexadecanoate, acetic acid, butanoic acid, 2/3-methyl butanoic acid, and tetramethyl-pyrazine. Three samples (CJW, SIN, and HAE) made by Aspergillus oryzae inoculation showed similar volatile patterns as shown in principal component analyses to GC-MS data sets, which showed higher levels in ethyl esters and 2-methoxy-4-vinylphenol. Traditional fermented soybean pastes showed overall higher levels in pyrazines and acids contents.