• Archives of Pharmacal Research
• /
• 제20권6호
• /
• pp.620-628
• /
• 1997

6-Aryl-5-cyano-4-pyrimidinon-2-thione derivatives 1a-c reacted with ethyl iodide to give the corresponded 2-S-ethylpyrimidin-4-one-derivatives 2a-c. Compounds 2a-c was, in turn, reacted with hydrazine hydrate to give the sulfur free reaction products, 3a-c. These reaction products were taken as the starting materials for the synthesis of several newly synthesized heterocyclic derivatives. Reactions with several halogenated ketones, esters, chloroacetic acid and chloroacetamide give pyrimidotriazines 8,12 and 15 while their reactions with formic acid, acetic acid and carbon disulfide gave the corresponded triazolopyrimidines 17 and 21. The reaction with both acetyl acetone and ethylacetoacetate gave the corresponded 2-$(3^{I},5^{I}-dimethyl-1^{I}-pyrazoly$pyrimidine derivatives 20a-c and 24a-c respectively while the reaction with cinnamonitriles 25a-h afforded the corresponded aryl hydrazopyrimidines 27a-f. The structure of these reaction products were eatablished based on both elemental anlayses and spectral data studies.

• Bulletin of the Korean Chemical Society
• /
• 제15권2호
• /
• pp.154-161
• /
• 1994

Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethylthioalkyl)phthalimides (alkyl=ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl). Photocyclizations occur in methanol in modest to high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from sulfur in the ${\alpha}$-silylmethylthioalkyl groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate ${\alpha}$ -silylmethylthio cation radicals and cyclization by radical coupling is proposed. In contrast, photoreactions of N-(trimethylsilylmethylthioalkyl)phthalimides in acetone follow different reaction routes to produce another cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon ${\alpha}$ to silicon and sulfur atoms via triplet carbonyl hydrogen abstraction pathway. The normal singlet SET pathway dominates this triplet process for photoreactions of these substances in methanol while the triplet process dominates the singlet SET pathway for those in acetone. The efficient and regioselective cyclization reactions observed for photolyses in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.

• Bulletin of the Korean Chemical Society
• /
• 제13권2호
• /
• pp.166-172
• /
• 1992

Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethoxyalkyl)phthalimides(alkyl=E thyl, n-propyl, n-butyl, n-pentyl, and n-octyl). Photocyclizations occur in methanol in high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from oxygen in the $\alpha-silylmethoxy$ groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate $\alpha-silylmethoxy$ cation radicals and cyclization by radical coupling are proposed. In contrast, photoreaction of N-(trimethylsilylmethoxyethyl) phthalimide in acetone follows different reaction routes to produce two cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon $\alpha$ to silicon and oxygen atoms via triplet carbonyl hydrogen abstraction triplet carbonyl silyl group abstraction pathways. The normal singlet SET pathway dominates these triplet processes for photoreaction of this substance in methanol. The efficient and regioselective cyclization reactions observed for photolysis in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.

• Environmental Analysis Health and Toxicology
• /
• 제19권4호
• /
• pp.335-344
• /
• 2004

Diesel exhaust particle (<2.5 ${\mu}{\textrm}{m}$, DEP$_{2.5}$) is known to be probarbly carcinogenic (IARC group 2A). DEP$_{2.5}$ contains organic compounds such as polycyclicaromatic hydrocarbon (PAH), heterocyclic compounds, phenols, and nitroarenes. Reactive oxygen species (ROS) are generated by DEP$_{2.5}$ without any biological activation system. Therefore, an alternative mechanism by which DEP$_{2.5}$ could be carcinogenic is known by the generation of oxidative DNA damage. The aim of this study was to investigate genotoxic effects of DEP$_{2.5}$ using single cell gel electrophoresis. In order to evaluate the mechanisms of DEP$_{2.5}$ genotoxicity, the rat micro-some mediated and DNA repair enzyme treated comet assays together with routine comet assay were performed. DEP$_{2.5}$ was collected from diesel engine bus and dichloromethane extract was obtained. The organic extract of DEP$_{2.5}$ revealed DNA damage itself in NIH/3T3 cells. And it showed both oxidative and microsome mediated DNA damages. Vitamin C as an model antioxidant reduced DNA damage in endonuclase III treated comet assay. One of flavonoid, galangin as a CYP1A1 inhibitor reduced DNA damage in the presence of S-9 mixture. Our results show that DEP$_{2.5}$ are genotoxic and a great source of oxidative stress, but antioxidants can significantly reduce oxidative DNA damages. And DEP$_{2.5}$ may contain indirect mutagens which can be inhibited by CYP inhibitors.d by CYP inhibitors.

• Bulletin of the Korean Chemical Society
• /
• 제31권11호
• /
• pp.3304-3308
• /
• 2010

Condensation of 4-amino-5-mercapto-3-($\alpha$-naphthyl)-s-triazole (1) with cyanogen bromide gives 6-amino-3-($\alpha$-naphthyl)-s-triazolo[3,4-b]-1,3,4-thiadiazole (2) which on condensation with chloranil yields 3,9-di-($\alpha$-naphthyl)-6,14-dioxo-bis-(s-triazolo[3,4-b]-1,3,4-thiadiazolo[3,2-b]imidazo[4,5-b]cyclohexane]-5a,6a-diene) (3). 3-($\alpha$-naphthyl)-s-triazolo[3,4-b]-1,3,4-thiadiazolo[3,2-b]imidazo[4,5-b]quinoxaline (4) is obtained by a similar condensation of (2) with 2,3-dichloroquinoxaline. The reaction of (2) with $\alpha$-haloketones followed by bromination affords 7-aryl-3-($\alpha$-naphthyl)-imidazo[2,1-b]-1,3,4-thiadiazolo[2,3-c]-s-triazoles (5) and their 6-bromo analogues 6 respectively. The structures of all newly synthesized compounds were established on the basis of elemental analyses, IR, $^1H$-NMR. The antibacterial and antifungal activities of all newly synthesized compounds have also been evaluated.

• 대한화학회지
• /
• 제51권6호
• /
• pp.506-512
• /
• 2007

여러가지 긴 사슬 지방산 하이드라지드는 방향족과 헤테로 고리 알데히드와 반응하여 알코올 용매하에서 2- hydroxy benzylidene와 새로운 모기 파라-페로몬인1H-indol-3-ylmethylene hydrazides을 얻었다. 마이크로파의 조사기 술과 마찬가지로 전통적인 방법에 의한 다양한 새로운 긴고리 지방산 하이드라지드 (2-hydroxy benzylidene와 1Hindol- 3-ylmethylene)의 합성방법도 보고한다. 이 화합물들의 구조는 FTIR, NMR & MS와 같은 분광학적 기법에 의해 증명되었다. 이 화합물의 전자충격질량스펙트럼 분쇄 패턴의 몇 가지 재미있는 특징도 논의했다.

• 한국수산과학회지
• /
• 제19권2호
• /
• pp.127-135
• /
• 1986

D-glucose-glycine계로 부터 조제한 Maillard 반응생성물을 한외여과로 각 분자량별로 분획(분자량 1,000이하, $1,000{\sim}5,000$, 5,000이상)하고, 투석에 의하여 비투석성 melanoidin을, 오존처리에 의하여 오존처리 melanoidin을 각각 얻었다. 이들 각 시료를 아미노산 및 단백질의 가열분해 유래의 변이원성 물질인 TrP-P-1, TrP-P-2, Glu-P-1, Glu-P-2 및 IQ에 각각 작용($37^{\circ}C$, 30분) 시켜서, 변이원성억제효과를 검토하였다. 그 결과, Maillard반응생성물의 변이원성억제효과는 반응생성물의 분자량의 크기에 비례하여 높게 나타났다. Maillard 반응생성물의 환원력 및 항산화력 또한 분자량이 큰 획분일수록 크게 나타났다. 그러나, Sodium borohydride로 melanoidin을 환원시켰을 때, melanoidin의 변이원성억제효과 및 환원력이 감소하였다. 또한, Trp-P-1의 일부가 melanoidin 분자중에 흡착되는 것이 밝혀졌고, 카르 보닐화합물(diacetyl 및 glyceraldehyde)로 이들 변이원성물질의 아미노기를 수식함으로써 변이원성물질의 변이원활성이 크게 저하하였다. 따라서, Maillard 반응생성물 즉 melanoidin의 변이원성억제효과는 melanoidin의 환원력 및 항산화능을 비롯하여 정전기적인 흡착 및 melanoidin 분자중의 카르보닐기에 기인한다고 추찰된다.

• Bulletin of the Korean Chemical Society
• /
• 제33권5호
• /
• pp.1457-1464
• /
• 2012

An ecofriendly catalytic route for selective synthesis of $N$-substituted azacyclopentanes, nitrogen-containing heterocyclic intermediates for many bioactive compounds, was established by carrying out $N$-heterocyclization (di $N$-alkylation) of primary amines with 1,4-dichloro butane (as dialkylating agent) using catalytic amount of hydrotalcite as solid base catalyst. The hydrotalcite was found to be efficient solid base catalyst for di $N$-alkylation of different primary amines (aniline, benzyl amine, cyclohexyl amine and n-butyl amine) giving 82 to 96% conversion (at optimized reaction condition) of 1,4-dichloro butane and > 99% selectivity of respective $N$-substituted azacyclopentanes within 30 min. under solvent free condition. The reaction parameters significantly influence the conversion of 1,4-dichloro butane to $N$-substituted azacyclopentanes. The nature of substituent present on amino group affects the reactivity of amine substrates for di $N$-alkylation reaction with 1,4-dichloro butane. The 1,4-dichloro butane was found to be highly reactive alkylating agent for di $N$-alkylation of amines as compared to 1,4-dihydroxy butane. The reusability of the catalyst and its chemical stability in the reaction was demonstrated.

• Bulletin of the Korean Chemical Society
• /
• 제33권5호
• /
• pp.1505-1508
• /
• 2012

Protein tyrosine phosphatase 1B (PTP1B) is a key factor in negative regulation of the insulin pathway, and is a promising target for the treatment of type-II diabetes, obesity and cancer. Herein, compound ($\mathbf{4}$) was first observed to have moderate inhibitory activity against PTP1B with an $IC_{50}$ value of $13.72{\pm}1.53{\mu}M$. To obtain more potent PTP1B inhibitors, we synthesized a series of chalcone derivatives using compound ($\mathbf{4}$) as the lead compound. Compound $\mathbf{4l}$ ($IC_{50}=3.12{\pm}0.18{\mu}M$) was 4.4-fold more potent than the lead compound $\mathbf{4}$ ($IC_{50}=13.72{\pm}1.53{\mu}M$), and more potent than the positive control, ursolic acid ($IC_{50}=3.40{\pm}0.21{\mu}M$). These results may help to provide suitable drug-like lead compounds for the design of inhibitors of PTP1B as well as other PTPs.

• 한국환경과학회지
• /
• 제16권4호
• /
• pp.393-397
• /
• 2007

The sonolytic decomposition of NHCs(Nitrogen Heterocyclic Compounds), such as atrazine[6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], simazine(6-chloro-N,N'-diethyl-1,3,5-triazine-2,4-diamine), trietazine(6-chloro-N,N,N'-triethyl-1,3, 5-triazine-2,4-diamine), in water was investigated at a ultrasound frequency of 200kHz with an acoustic intensity of 200W under argon and air atmospheres. The concentration of NHCs decreased with irradiation, indicating pseudo-first-order kinetics. The rates were in the range $1.06{\sim}2.07({\times}10^{-2}min^{-1})$ under air and $1.30{\sim}2.59({\times}10^{-2}min^{-1})$ under argon at a concentration of $200{\mu}M$ of NHCs. The rate of hydroxyl radicals(${\bullet}{OH}$) formation from water is $19.8{\mu}M\;min^{-1}$ under argon and $14.7{\mu}M\;min^{-1}$ under air in the same sonolysis conditions. The sonolysis of NHCs is effectively inhibited, but not completely, by the addition of t-BuOH(2-methyl-2-propanol), which is known to be an efficient ${\bullet}{OH}$ radical scavenger in aqueous sonolysis. This suggests that the main decomposition of NHCs proceeds via reaction with ${\bullet}{OH}$ radical; a thermal reaction also occurs, although its contribution is small. The addition of appropriate amounts of Fenton's reagent $[Fe^{2+}]$ accelerates the decomposition. This is probably due to the regeneration of ${\bullet}{OH}$ radicals from hydrogen peroxide, which would be formed from recombination of ${\bullet}{OH}$ radicals and which may contribute a little to the decomposition.