• 대한화학회지
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• 제31권5호
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• pp.413-418
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• 1987

파라니트로 염화벤질(p-NO$_2$), 염화벤질(p-H) 및 파라메틸 염화벤질(p-CH$_3$)과 피리딘 사이의 반응을 메탄올용매내에서 반응시켜 이들의 반응 온도를 40$^{\circ}$C 와 50$^{\circ}$C로 하고, 압력은 1∼2000bar로 변화시켜 전기전도도법으로 측정하여 유사 1차 반응속도 상수와 2차 반응속도 상수를 구하였다. 이때 반응속도 상수는 p-NO$_2$ < p-H < p-CH$_3$의 순으로 증가됨을 알았다. 염화벤질류와 피리딘의 반응속도상수는 온도, 압력이 증가함에 따라 증가하고 피리딘의 농도가 증가할수록 증가하였다. 상기 반응속도 상수로 부터 활성화부피, 활성화 압축율 계수, 활성화엔탈피, 활성화 엔트로피 및 활성화 자유에너지를 구하였다. 활성화 부피와 활성와 압축율 계수는 모두 음의 값이며, 활성화 엔탈피는 양의 값을 활성화 엔트로피는 큰 음의 값을 나타내었다. 이러한 사실로부터 치환체 및 압력에 따른 초기상태와 전이상태를 비교 검토하여 반응메카니즘을 고찰한 결과 전체반응은 S$_N$2반응으로 진행되고 있으나, 압력이 증가함에 따라 S$_N$2반응성이 약화됨을 알았다.

• 폴리머
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• 제32권4호
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• pp.295-304
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• 2008

This study examined the oxidative polycondensation reaction of 2-[(pyridin-4-yl-) methyleneamino] pyridine-3-ol (2-PMAP) using air $O_2$ and NaOCl oxidants at various temperatures and times in aqueous alkaline and acidic media. Under these reactions, the optimum reaction conditions using air $O_2$ and NaOCl oxidants were determined for 2-PMAP. The number-average molecular weight ($M_n$), weight average molecular weight ($M_w$), and polydispersity index (PDI) values of O-2-PMAP synthesized in aqueous alkaline media were found to be 960, 1230, and $1.281\;g\;mol^{-1}$ using NaOCl, and 1030, 1520, and $1.476\;g\;mol^{-1}$ using air $O_2$, respectively. At the optimum reaction conditions, the yield of O-2-PMAP in aqueous alkaline media was 92.50% and 85.70% for air $O_2$ and NaOCl oxidants, respectively. The yield of O-2-PMAP in aqueous acidic media was 88.5% and 88.0% for NaOCl and air $O_2$ oxidants, respectively. O-2-PMAP was characterized by $^1H-$, $^{13}C$-NMR, FT-IR, UV-vis, SEC, and elemental analysis. TGA-DTA analysis revealed O-2-PMAP and its oligomer metal complex compounds, such as $Co^{+2}$, $Ni^{+2}$, and $Cu^{+2}$, to be stable against thermal decomposition and their weight losses at $1000^{\circ}C$ were found to be 73.0, 58.0, 53.5%, and 50.0%, respectively. In addition, the antimicrobial activities of the monomer and oligomer were tested against E. Coli (ATCC 25922), E. Faecelis (ATCC 29212), P. Auroginasa (ATCC 27853), and S. Aureus (ATCC 25923).

• Archives of Pharmacal Research
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• 제28권11호
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• pp.1205-1212
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• 2005

2-Thiouracil-5-sulphonic acid N-(4-acetylphenyl) Amide (1) was reacted with a series of aromatic aldehydes giving chalcones 2 (Claisen-Schemidt reaction), some of these chalcones were reacted with urea and thiourea giving pyrimidine-2-one and pyrimidine-2 thione derivatives respectively of the type 3a,b and 4a,b. In addition many chalcones were reacted with hydroxylamine hydrochloride giving isoxazoline derivatives 5a,b. They could also reacted with phenylhydrazine to give pyrazoline derivatives 5a,b, chalcones also were reacted withethylcyano acetate and/or malononitryl in pyridine giving pyran derivatives 7a,c and 8a,c. In another pathway chalcones were epoxidised by $H_{2}O_{2}$ giving epoxides 9a,c which in turn were reacted with phenylhydrazine giving 4-hydroxypyrazoline derivatives 10a,c. In another reaction chalcones were reacted with ethylcyanoacetate in presence of amm.acetate giving pyridone derivatives 11a,d which could be prepared also in exellent yield from compound 1 by its reaction with certain aromatic aldehydes and ethylcyanoacetate in presence of ammonium acetate. Finally, compound 1 was reacted with semicarbazide giving semicarbazone intermediate 12 which in turn was reacted with thionyl chloride giving thiadiazole derivative 13. The biological effects of some of the new synthesized compounds were also investigated.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1460-1464
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• 2014

The substituent effects on the pyridinolysis (XC5H4N) of Y-aryl ethyl chlorophosphates are investigated in acetonitrile at $35.0^{\circ}C$. The two strong ${\pi}$-acceptor substituents, X = 4-Ac and 4-CN in the X-pyridines, exhibit large positive deviations from the Hammett plots but little positive deviations from the Br$\ddot{o}$nsted plots. The substituent Y effects on the rates are really significant and the Hammett plots for substituent Y variations in the substrates invariably change from biphasic concave downwards via isokinetic at X = H to biphasic concave upwards with a break point at Y = 3-Me as the pyridine becomes less basic. These are interpreted to indicate a mechanistic change at the break point from a stepwise mechanism with a rate-limiting bond formation (${\rho}_{XY}$ = -6.26) for Y = (4-MeO, 4-Me, 3-Me) to with a rate-limiting leaving group expulsion from the intermediate (${\rho}_{XY}$ = +5.47) for Y = (4-Me, H, 3-MeO). The exceptionally large magnitudes of ${\rho}_{XY}$ values imply frontside nucleophilic attack transition state.

• Bulletin of the Korean Chemical Society
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• 제18권6호
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• pp.653-656
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• 1997

The new unsymmetric $N_6$ ligand 1-amino-13-(2-pyridyl)-3,6,9,12-tetraazatridecane (aptatd) containing one pyridyl group has been synthesized and characterized by EA, IR, and NMR. Its proton association constants $(log K_H^n)$ and stability constants $(log K_{ML})$ for Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) ions were determined at 298.1 K and ionic strength 0.100 mol $dm^{-3}$ (KNO₃) in aqueous solution by potentiometry: log $K_H^1$=8.80, log $K_H^2$=8.49, log $K_H^3$=6.84, log $K_H^4$=4.17, log $K_H^5$=3.47; log $K_{ML}(Co^{2+})$=18.00, log $K_{ML}(Ni^{2+})$=21.31, log $K_{ML}(Cu^{2+})$=23.62, log $K_{ML}(Zn^{2+})$=15.60. The X-ray structure of its nickel(Ⅱ) complex [Ni(aptatd)]$(ClO_4)_2$ are reported: orthorhombic space group Pbca, a=15.715(1) Å, b=14.280(2) Å, c=19.443(2) Å, V=4363.4 (9) ų with Z=8. The geometry around nickel is a distorted octahedron with the pyridine nitrogen atom being cis to the nitrogen atom of the terminal primary amine.

• Bulletin of the Korean Chemical Society
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• 제25권7호
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• pp.1041-1045
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• 2004

Kinetic studies of the pyridinolysis $(XC_5H_4N)$ of aryl dithiomethylacetates $(CH_3CH_2C(=S)SC_6H_4Z,\;1)$ are carried out in acetonitrile at $60.0^{\circ}C$. A biphasic Bronsted plot is obtained with a change in slope from a large $({\beta}X\;{\cong}\;0.8)$ to a small $({\beta}X\;{\cong}\;0.2)$ value at $pK_a^{\circ}$ = 5.2, which is attributed to a change in the rate limiting step from breakdown to formation of a zwitterionic tetrahedral intermediate, $T^{\pm}$, in reaction path as the basicity of the pyridine nucleophile increases. This mechanism is supported by the change of the cross-interaction constant ${\rho}xz$ from a large positive ( ${\rho}xz$ = +1.36) for the weakly basic pyridines to a small negative ( ${\rho}_xz$ = -0.22) value for the strongly basic pyridines. The magnitudes of ${\rho}z$ and activation parameters are also consistent with the proposed mechanism.

• 통합자연과학논문집
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• 제7권2호
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• pp.92-102
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• 2014

The crystal structure of the title compounds with both coumarin and sulfonamide moieties were examined. These two groups have very special for their pharmaceutical and medicinal properties have been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the monoclinic space group C2/c with unit cell dimension a = 28.633(3) ${\AA}$, b= 9.3215(7) ${\AA}$ and c= 24.590(2) ${\AA}$ [alpha & gamma=$90^{\circ}$ beta= $115.976(3)^{\circ}$]. In the structure The S1 atom shows a distorted tetrahedral geometry, with O1-S1-O2 [119.74 $(2)^{\circ}$] and N1-S1-C5 [$105.57(1)^{\circ}$] angles deviating from ideal tetrahedral values are attributed to the Thrope-Ingold effect. The sum of bond angles around N1 ($316.2(1)^{\circ}$) indicates that N1 is in sp2 hybridization. The Pyridine ring adopts boat conformation and pyran rings adopt a sofa conformation. The carboxylate group of atoms were disordered over two positions with site occupancy factors 0.598 (9):0.402 (9). Crystal structure and packing is stabilized by $C-H{\ldots}O$ intra and inter molecular hydrogen bond interactions.

• 통합자연과학논문집
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• 제7권3호
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• pp.149-158
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• 2014

The crystal structure of the title compounds with both coumarin and sulfonamide moieties were examined. These two groups have very special for their pharmaceutical and medicinal properties have been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the monoclinic space group $P2_1/c$ with unit cell dimension a=$8.5775(4){{\AA}$, b=$24.9943(13){\AA}$ and c=$13.7319(7){\AA}$ [alpha & gamma=$90^{\circ}$ beta=$103.558(2)^{\circ}$]. In the structure The S1 atom shows a distorted tetrahedral geometry, with O1-S1-O2 [$121.08(1)^{\circ}$] and N1-S1-C5 [$105.85(1)^{\circ}$] angles deviating from ideal tetrahedral values are attributed to the Thrope-Ingold effect. The sum of bond angles around N1 ($354.9^{\circ}$) indicates that N1 is in $sp^2$ hybridization. The Pyridine ring adopts boat conformation and pyran rings adopt a sofa conformation. Crystal structure is stabilized by C-H...O intra molecular hydrogen bond interactions.

• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2642-2646
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• 2012

Pretreatment of spent FCC catalyst and its application in remove trace olefins in aromatics were investigated in this research. The most effective pretreatment route of spent FCC catalyst was calcining at $700^{\circ}C$ for 1 h, washing with 5% oxalic acid solution in ultrasonic reactor and dried. Treated spent FCC catalyst was modified with metal halides, then to prepare catalyst to remove trace olefins in aromatics. X-ray diffraction, Pyridine-FTIR, $N_2$ adsorption-desorption and inductively coupled plasma optical emission spectrometer (ICP-OES) were used to investigate the pretreatment process. The result showed that the performance of the treated spent FCC catalyst was much greater than that of the spent FCC catalyst, which indicted the possibility and improvement of this research.

• 대한화학회지
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• 제39권9호
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• pp.715-721
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• 1995

Trans-$[Co(py)_4/Ci_2]^+(py=pyridine)$과 L-proline 및 diimine(=2,2'-bipyridine,1,10-phenanthroline)과의 반응에서 $[Co(L-pro)_2/(bipy)]^+$(L-pro=bipy=2,2'-bipyridine)과 $[Co(L-pro)_2(phen)]^+$(phen=1,10-phenathroline)이 각각 생성되었다. 관 크로마토그래피상에서 입체특이성을 가지는 L-prolinato의 입체선택성으로 인하여 $[Co(L-pro)_2(bipy)]^+$에서는 $Lambda$-trans(N)만이 얻어졌고 $[Co(L-pro)_2(bipy)]^+$에서는 ${\Delta}$-trans(N)과 $Lambda$-cis(O)cis(N)이 얻어졌다. 결정구조 연구의 결과는 다음과 같다: $Lambda$-trans(N)-$[Co(L-pro)_2(bipy)]CIO_4{\cdot}2H_2O$ (1): monoclinic, space group $P2_1(#4)$, a = 9.807(3), b = 10.421(1), c = 12.778(2)${\AA}$, ${\beta}=109.90(2)^{\circ}$, V = 1227.8(5)${\AA}^3$, Z = 2; 1571 data(I>3.0${\sigma}$(I)) R = 0.060 and $R_W = 0.067$; ${\Delta}$-trans(N)-$[Co(L-pro)_2(phen)]Cl{\cdot}_3H_2O$ (2): monoclinic, space group $P2_1(#4)$, a = 9.838(2), b = 12.892(2), c = 10.747(2)${\AA}$, ${\beta}=113.79(2)^{\circ}$, V = 1247.2(4)${\AA}^3$, Z = 2; 2433 data(I>3.0${\sigma}$(I)) R = 0.043 and $R_W = 0.050$.