• Bulletin of the Korean Chemical Society
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• 제21권6호
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• pp.613-617
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• 2000

p-(2-Vinyloxyethoxy)benzylidenemalononitrile (4a), methyl p-(2-vinyloxyethoxy)benzylidenecyanoacetate (4b), 3,5-dimethoxy-4-(2'-vinyloxyethoxy)benzylidenemalononitrile (5a), methyl 3,5-dimethoxy-4-(2'-vinyloxy-ethoxy) benzylidenecyanoacetate (5 b), o-(2 -vinyloxyethoxy)benzylidenemalononitrile (6a), methyl o-(2-viny-Ioxyethoxy) benzylidenecyanoacetate (6b), 1,3-di-(2',2'-dicyanovinyl)-5-methyl-2-(2'-vinyloxyetioxy)benzene (7a), l,3-di-(2'-carbomethoxy-2'-cyanovinyl)-5-methyl-2-(2'-vinyloxyethoxy)benzene (7b), 2,3,4-tri-(2'-viny-Ioxyethoxy) benzylidenemalononitrile (8a), methyl 2,3,4-tri-(2'-vinyloxyethoxy)benzylidenecyanoacetate (8b), 2,4,6-tri-(2'-vinyloxyethoxy)benzylidenemalononitrile (9a), and methyl 2,4,6-tri-(2'-vinyloxyethoxy)benzyl-idenecyanoacetate(9b) were prepared by the condensation of the corresponding benzaldehyde 1-3 with malononitrile or methyl cyanoacetate, respectively. Vinyl ether monomers 4, 6, and 8 polymerized readily with radical initiators to yield crosslinked polymers 10, 12, and 14. However, compounds 5, 7, and 9 were inert to radical initiators due to the steric hindrance. The resulting polymers 10, 12, and 14 were not soluble in common solvents showing a thermal stability up to $300^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.269-273
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• 2003

The synthesis and properties of 2,13-bis(3'-pyridylmethyl) $(L^3)$, 2,13-bis(4'-pyridylmethyl) $(L^4)$, and 2,13-bis(phenylmethyl) $(L^5)$ derivatives of 5,16-dimethyl-2,6,13,17-tetraazatrcyclo$[16.4.0.^{1.18}0^{7.12}]$docosane are reported. The 3- or 4-pyridylmethyl groups of $[ML^3](ClO_4)_2\;or\;[ML^4](ClO_4)_2$ (M = Ni(Ⅱ) or Cu(Ⅱ)) are not involved in coordination, and the coordination geometry (square-planar) and ligand field strength of the complexes are quite similar to those of $[ML^5](ClO_4)_2$, bearing two phenylmethyl pendant arms. However, the complex formation reactions of $L^3\;and\;L^4$ are strongly influenced by the pyridyl groups, which can interact with a proton or metal ion outside the macrocyclic ring. The macrocycle $L^5$ exhibits a high copper(Ⅱ) ion selectivity against nickel(Ⅱ) ion; the ligand readily reacts with copper(Ⅱ) ion to form $[CuL^5]^{2+}$ but does not react with hydrated nickel(Ⅱ) ion in methanol solutions. On the other hand, $L^3\;and\;L^4$ form their copper(Ⅱ) and nickel(Ⅱ) complexes under a similar condition, without showing any considerable metal ion selectivity. The ligands $L^3\;and\;L^4$ react with copper(Ⅱ) ion more rapidly than does $L^5$ at pH 6.4. At pH 5.0, however, the reaction rate of the former macrocycles is slower than that of the latter. The effects of the 3- or 4-pyridylmethyl pendant arms on the complex formation reaction of $L^3\;and\;L^4$ are discussed.

• 한국염색가공학회지
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• 제14권4호
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• pp.229-239
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• 2002

Colorants were extracted from the heartwood of sappan lin. with MeOH under reflux, and the concentrate or the powder of dye was prepared by low pressure concentration method using suitable organic solvent. Various components were isolated from sappan wood, and the chemical structure and mechanism of compound having the excellent antibacterial and deodorization properties were analyzed. The results obtained are as follows ; The seventeen components of sappan wood were seperated by HPLC chromatography, and the five components among them were existed more than 6% and the other components were existed lower than 0.6%. The resolving powers of the non-polar solvent and polar solvent systems were evaluated by their ability to resolve the samples. It showed that chloroform-methanol-water(800:150:10) system has the best resolving power. Although the seperation rate is very slow, polyamide C-100 column chromatography gives a clear seperation of sappan wood. On the basis of the spectrometric data such as IR, UV, $GC-Mass,\;^1H-NMR,\;^{13}C-NMR\;and\;^1H-^{ 13}C-NMR$, the chemical structure of compound haying the excellent antibacterial and deodorization properties was established as brazilin containing the functional groups such as two quaternary carbon, one benzyl carbon, methylene contiguous to oxygen and methylene caused by oxygen atom.

• 공업화학
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• 제7권1호
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• pp.171-176
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• 1996

환경 친화성인 비이온 계면활성제 글루카마이드(N-알킬-N-아실 글루카민)는 크게 두 단계 반응으로 구분되는데, 첫 단계는 알킬 아민과 글루코스를 메탄올 용매하에 아민화 반응시킨 후, Ni 촉매하에 고압으로 환원시킨 결과 4종의 알킬 글루카민을 86~93%의 수율로 얻었다. 2단계 반응에서는 4종의 알킬 글루카민과 4종의 지방산 메틸 에스테르를 알칼리 촉매하에 메탄올을 환류시키면서 합성한 결과 16종중 12종의 글루카마이드는 84~95%수준의 높은 수율을 보였으나, 알킬기가 벤질일 경우에는 50~70%의 낮은 수율을 나타내었다. 알킬 글루카민 4종과 글루카마이드 16종에 대한 분자구조 확인은 IR, MS, NMR로 확인하였다.

• Toxicological Research
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• 제19권4호
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• pp.297-301
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• 2003

To investigate biomarker-based exposure to phthalates and related factors with demographics, 100 subjects who had participated in comprehensive health check-up were selected. We collected demographics through questionnaires and analyzed urine samples for 5 phthalates. Statistical likelihoods and regression methods were applied for data analysis using censored data. The highest levels of urine phthalates were 216$\mu\textrm{g}$/ml in di-isodecyl phthalate, 29.0$\mu\textrm{g}$/ml in di-butyl phthalate, 5.78$\mu\textrm{g}$/ml in di-(2-ethylhexyl) phthalate. The median values of di-(2-ethylhexyl) phthalate were 0.2340 $\mu\textrm{g}$/ml for male smokers, 0.0399 $\mu\textrm{g}$/ml for male non-smokers and 0.0085 $\mu\textrm{g}$/ml for female non-smokers, respectively. Di-(2-ethylhexyl) phthalate, benzyl butyl phthalate and di-isodecyl phthalate were higher in males than in females. In addition, mono-2-ethylhexyl phthalate was decreased with age. Our findings suggest that there might be significant demographic variations in exposure and/or metabolism of phthalates, and that health-risk assessment for phthalate exposure in humans should consider different potential risk groups.

• Archives of Pharmacal Research
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• 제26권10호
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• pp.778-784
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• 2003

N'-(1-alkyl-2,3-dihydro-2-oxo-1H-3-indolyliden)-4-pyridinecarboxylic acid hydrazide derivatives, 3(a-g), were synthesized in a trial to overcome the resistance developed with the therapeutic uses of isoniazid (INH). The lipophilicity of the synthesized derivatives supersedes that of the INH as expressed by Clog p values. The synthesized compounds and INH were tested against bovin, human sensitive and human resist strains of Mycobacterium tuberculosis. Compounds 3a, 3d, 3f and 3g with 1-unsubstituted, 1-propyl, 1-propynyl and 1-benzyl groups respectively exhibited equipotent growth inhibitory activity (MIC 10 $\mu$mol) against the tested strains as compared with INH however the later has no activity against human resist strain. Pharmacokinetic study revealed that the rate and extent of absorption of the tested derivatives (3d and 3f) significantly higher than that of INH (p＜0.05). The relative bioavailabilities ($F_R%$) were 183.15 and 443.25 for 3f and 3d respectively as compared to INH. These results preliminary indicate the possible use of the prepared derivatives for treatment of tuberculosis infections in order to overcome the resistance developed with INH.

• Bulletin of the Korean Chemical Society
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• 제8권3호
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• pp.168-170
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• 1987

The reaction between 1-benzyl-3-carbamoyl-1,4-dihydropyridine (BNAH) 1 and various 1-arylpyridinium salts 2, and the reaction between 1-(4-methylphenyl)-1,4-dihydropyridine 4b and 1-aryl-3-carbamoylpyridinium (1-arylnicotinamide) salts 5 were carried out. The extents of reaction in equilibrium were estimated by nmr integration data. The equilibrium constants for the reactions, K, and the standard Gibbs free energy changes for the reduction of the pyridinium salts to the corresponding 1,4-dihydropyridines ${\Delta}G^{\circ}'$ were evaluated. The Hammett plot of log K for the reaction between 1 and 2, and ${\Delta}G^{\circ}'$ against ${\sigma}_p$ of the substituents in 1-aryl moiety shows linear correlation with the reaction constant ${\rho}$ of 9.4 (for log K vs ${\sigma}_p$) and -54.5 KJ/mole (for ${\Delta}G^{\circ}'$ vs ${\sigma}_p$). It was found that 1-aryl-1,4-dihydropyridines have much higher reducing power than the corresponding 1-aryl-1,4-dihydronicotinamides, and the power is affected greatly by the electron-withdrawing ability of the substituents in aryl group. The reactions were utilized for preparation of 1,4-dihydropyridines bearing highly electron-withdrawing groups such as 4-nitrophenyl and 2,4-dinitrophenyl, which could not be obtained by conventional dithionite reduction of the corresponding pyridinium salts due to the base-labile nature of the salts.

• Mass Spectrometry Letters
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• 제13권4호
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• pp.125-132
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• 2022

There are many types of spring blossoms on the Daedeok campus of Chungnam National University (CNU) at the area of 1,600,000 square meters. As an assignment for the class of Analytical Chemistry I for second-year undergraduate students, 2021, flower petals collected from various floral groups (Korean azalea, Korean forsythia, Dilatata lilac, Lilytree, Lily magnolia, and Prunus yedoensis) were analyzed using headspace extraction coupled to gas chromatography-mass spectrometry (HS-GC-MS) to study the aromatic profiles and fragrance compounds of each sample group. Various types of compounds associated with the aroma profiles were detected, including saturated alcohols and aldehydes (ethanol, 1-hexanol, and nonanal), terpenes (limonene, pinene, and ocimene), and aromatic compounds (benzyl alcohol, benzaldehyde). The different contribution of these compounds for each floral type was visualized using statistical tools and classification models based on principal component analysis with high reliability (R² = 0.824, Q² = 0.616). These results showed that HS-GC-MS with statistical analysis is a powerful method to characterize the volatile aromatic profile of biological specimens.

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.2971-2975
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• 2012

Second-order rate constants $k_N$ have been measured spectrophotometrically for nucleophilic substitution reactions of t-butyl 4-pyridyl carbonate 8 with a series of alicyclic secondary amines in $H_2O$ at $25.0{\pm}0.1^{\circ}C$. The Br${\emptyset}$nsted-type plot for the reactions of 8 is linear with ${\beta}_{nuc}$ = 0.84. The ${\beta}_{nuc}$ value obtained for the reactions of 8 is much larger than that reported for the corresponding reactions of t-butyl 2-pyridyl carbonate 6 (i.e., ${\beta}_{nuc}$ = 0.44), which was proposed to proceed through a forced concerted mechanism. Thus, the aminolysis of 8 has been concluded to proceed through a stepwise mechanism with a zwitterionic tetrahedral intermediate $T^{\pm}$, in which expulsion of the leaving-group from $T^{\pm}$ occurs at the rate-determining step (RDS). In contrast, aminolysis of benzyl 4-pyridyl carbonate 7 has been reported to proceed through two intermediates, $T^{\pm}$ and its deprotonated form $T^-$ on the basis of the fact that the plots of pseudo-first-order rate constant $k_{obsd}$ vs. amine concentration curve upward. The current study has demonstrated convincingly that the nature of the leaving and nonleaving groups governs the reaction mechanism. The contrasting reaction mechanisms have been rationalized in terms of an intramolecular H-bonding interaction, steric acceleration, and steric inhibition.

• 폴리머
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• 제26권1호
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• pp.28-36
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• 2002

본 연구에서는 바이오칩 등에 응용 가능한 전도성 고분자 필름을 제조하기 위해 3-triophene acetic acid을 선택하여, 쉽게 전기적으로 산화되어 전기적 활성을 나타내는 고분자들을 형성하였다. 3-Thiophene acetic acid에 있는 카르복실기의 보호기들은 solid state에서 쉽게 제거되어질 수 있고, 그 결과 반응성 카르복실기가 전기적 활성을 나타내는 고분자 표면 위에 재생되어질 수 있었다. 즉, 카르복실기의 보호를 통한 전기중합과 뒤이은 보호기의 제거로 반응성인 카르복실기를 갖는 새로운 고분자 담체를 제조할 수 있었고, 기존의 방법으로 합성한 macromonomer를 필름 표면에 도입하여 전기적 활성을 나타내며 동시에 고분자 전해질이 도입된 전도성 고분자 필름을 얻었다. 합성한 전도성 단량체들과 macromonomer의 도입여부는 FT-IR과 $^1H-NMR$ 및 ESCA측정으로 확인하였고, 전극표면에 형성된 필름들의 형태는 SEM을 통해서 관찰하였다. 전기적 활성은 cyclic voltammogram(CV)을 통하여 확인하였으며, 얻어진 고분자 필름들은 0.7~0.9 V의 영역에서 전형적인 poly(3-alkylthiophene)의 전기 화학적 거동을 나타내었다.