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이석우,장병만,이광일,이기창,Suck-Woo Lee,Byung-Man Jang,Gwang Il Lee,Gi Chang Lee 대한화학회 1992 대한화학회지 Vol.36 No.6
N-Benzylidenebenzenesulfonamide 유도체의 가수분해 반응속도를 $25^{\circ}C$의 수용액에서 자외선 분광기를 사용하여 측정하고 넓은 pH 범위에 적용될 수 있는 반응속도식을 유도하였다. 가수분해 반응속도에 미치는 치환기 효과를 검토하기 위하여 Hammett plot를 한 결과 전자 끄는기에 의하여 반응속도가 촉진됨을 알 수 있었다. 가수분해 최종 생성물은 benzenesulfonamide와 benzaldehyde 이었으며 가부분해 반응속도 상수 측정과 반응속도식의 유도, 치환기 효과, general base 효과 및 최종생성물의 결과로부터 n-benzylidenebenzenesulfonamide 유도체의 가수분해 반응은 pH 0.2${\sim}$2.5에서는 hydronium ion에 의해서, pH 3.0${\sim}$8.0 사이에서는 중성의 물분자에 의하여 가수분해가 일어나고 pH 8.5 이상에서는 hydroxide ion에 의하여 진행됨을 알 수 있었다. The kinetics of the hydrolysis of N-benzylidenebenzenesulfonamide derivatives have been investigated by ultraviolet spectrophotometry in $H_2O$ at $25^{\circ}C$. A rate equation which can be applied over a wide pH range was obtained. The substituent effect on the hydrolysis of N-benzylidenebenzenesulfonamide derivatives were studied and rate of hydrolysis is known to be accelerated by electron withdrowing group. Final product of the hydrolysis was benzenesulfonamide and benzaldehyde. Base on the rate equation, substituent effect, general base effect and final products, hydrolysis of N-benzylidenebenzenesulfonamide derivatives seemed to be initiated by the hydronium ion at the pH 0.2${\sim}$2.5 and proceeded by the neutral $H_2O$ molecule at pH 3.0${\sim}$8.0 but proceeded by the hydroxide ion at above pH 8.5.
배양포유동물세포에서 환경돌연변이원에 의해 유발된 자매염색분체교환의 분석에 관한 연구
이석우,남정구,남재환,이병광,김은영,이승길 ( Sok Woo Lee,Joung Koo Nam,Jae Hwan Nam,Byoung Kwang Lee,Eun Young Kim,Seung Gil Lee ) 한국환경생물학회 1991 환경생물 : 환경생물학회지 Vol.9 No.2
The assay of SCEs has been used to measure mutagenicity induced several mutagens to high vertebrates. In this study, we used BHK-21, CHO-K1 and human peripheral lymphocyte as culture cell, and calcium chloride dihydrate(CaCl_2·2H_2O), sodium hypochloride(NaOCl), phenol(C_6H_5OH), benzo(a)pyrene(C_20H_12), carbon tetrachloride(CCl_4) and chloroform(CHCl_3) as mutagens. We examined and compared frequency between spontaneous and induced SCEs by mutagens. The mean spontaneous SCEs of human lymphocyte from 4 donors is scored 6.92±1.54(SCEs/cell) and BHK-21 is scored 0.18±0.03(SCEs/chromosome) and CHO-K1 is scored 0.61±0.08(SCEs/chromosome). In order to decided concentration of mutagens which is enough to induce SCEs and to effect SCEs score, we observed cell cytotoxicity and cell metaphase dependent on several concentration of mutagens. And then, using that concentration as control, we examined SCEs frequency induced three different concentration of mutagen. The increase of SCEs frequency induced by calcium chloride dihydrate is very little, but benzo(a)pyrene and phenol are great increase. Especially, we cannot find metaphase over 0.006mM benzo(a)pyrene and 1mM phenol. Although the increase of SCEs frequency induced by CHCl_3 is little, we observed many acentromeric chromosome in cell culture over 25mM CHCl_3. And we detected that SCEs frequency related with chromosome length of test cell.
${\alpha}$-(n-Butyl)-N-Phenylnitrone유도체의 가수분해 반응메카니즘과 반응속도론적 연구
이석우,곽천근,이광일,이기창,Lee Seok-Woo,Chun-Geun Kwak,Kwang-Il Lee,Lee Ki-Chang 대한화학회 1992 대한화학회지 Vol.36 No.4
${\alpha}$-(n-butyl)-N-phenylnitrone 유도체들의 가수분해 반응속도상수를 $25^{\circ}C$의 수용액에서 자외선 분광광도법으로 측정하여 넓은 pH 범위에서 잘 맞는 반응속도식을 구하였다. 반응속도식, 가수분해 생성물, 일반염기(general base) 및 치환기 효과 등의 결과로부터 가수분해 반응메카니즘을 제안하였다. 즉, pH 4.5이하에서의 가수분해는 양성자가 첨가된 nitrone의 ${\alpha}$-탄소에 물분자의 공격에 의해 진행되며, pH 10.0 이상에서는 ${\alpha}$-탄소에 히드록시 이온의 직접 첨가에 의하여 가수분해가 진행된다. pH 4.5∼10.0에서는 nitrone에 물분자가 첨가되는 것이 속도결정단계임을 알았다. The rate constants of hydrolysis of ${\alpha}$-(n-butyl)-N-phenylnitrone and its derivatives have been determined by UV spectrophotometry at 25$^{\circ}C$ and a rate equation which can be applied over a wide pH range was obtained. On the basis of rate equations derived and judging from the hydrolysis products obtained and from general base and substituent effects, plausible mechanisms of hydrolysis in various pH range have been proposed. Below pH 4.5, the hydrolysis was initiated by the protonation and followed by the addition of water to ${\alpha}$-carbon. Above pH 10.0, the hydrolysis was proceeded by the addition of hydroxide ion to ${\alpha}$-carbon. In the range of pH4.5∼10.0, the addition of water to nitrone is rate controlling step.
이석우,Lee, Seok-U 대한출판문화협회 1998 출판저널 Vol.231 No.-
고야는 인간의 어두운 내면을 폭로하고, 인간의 자유를 박탈하는 모든 것을 파헤치고, 이를 그림으로 고발하는 엄정한 저항정신의 소유자였다. 그것이 종교적 위엄을 갖춘 것이든 광인이나 악마들의 향연이든 그림의 진실 속에 담아내기를 주저하지 않았다.