• 대한화학회지
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• 제27권5호
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• pp.368-375
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• 1983

5-아릴-1,3,4-옥시티아졸-2-온을 트리에틸포스파이트와 반응시키면 탈황반응에 의해 벤조니트릴과 에틸포스포로티오에이트가 66~94% 수득율로 얻어졌다. 다른 3가의 인화합물 즉, 트리메틸포스파이트, 트리에틸포스핀, 그리고 트리페닐포스핀들과도 같은 탈황반응이 관찰되었다. 그러나 트리페닐포스파이트와는 전혀 반응하지 않았다. 5-아릴-1,3,4-디티아졸-2-온을 트리페닐포스핀과 반응시키면 티오아실 이소시아네이트가 얻어졌다. 이것은 에테르에서 자체적으로 분해되어 벤조니트릴로 변하게 되나 클로로포름에서는 안정하다. 이 두 반응에서 관찰되는 탈황반응은 인이 고리속으로 들어가 고리를 늘인후 분자내에서의 자리옮김 반응에 의해 일어나는 것이라 생각된다. 클로로포름에서 안정한 티오아실 이소시아네이트는 이민과 1,4-고리화 첨가반응을 일으켜 티아다이아지논을 생성하였다.

• 폴리머
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• 제39권1호
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• pp.165-168
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• 2015

하이드록시 그룹을 지닌 온도민감형 고분자들이 원자전이라디칼중합법(ATRP)과 클릭반응(click reaction)에 의해 합성되어졌다. 고분자들의 분자량과 분자량 분포도는 gel permeation chromatography(GPC)에 의하여 얻어졌고, 고분자들의 분자량은 잘 제어되었으며 분자량 분포도도 낮게 유지되었다. 클릭반응의 효율은 $^1H$ NMR spectroscopy에 의해 얻어졌으며, 높은 효율을 나타내었다. 고분자 사슬 곁가지의 아민 그룹의 종류와, 치환된 알코올 그룹의 종류에 따라 저임계 용액 온도(LCST)의 제어가 가능했다.

• Bulletin of the Korean Chemical Society
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• 제8권2호
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• pp.96-101
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• 1987

2-Ethoxy-6-methoxy-5-cyano-3,4-dihydro-2H-pyran (1_a$), 2-n-butoxy-6-methoxy-5-cyano-3,4-dihydro-2H-pyr an (1b), 2-isobutoxy-6-methoxy-5-cyano-3,4-dihydro-2H-py ran ($1_c$), and 2-ethoxy-6-methoxy-3-methyl-5-cyano-3,4-dihydro -2H-pyran ($1_d$) were prepared by (4 + 2) cycloaddition reaction of methyl $\alpha$-cyanoacrylate with the corresponding alkyl vinyl ethers. Compounds $1_{a-d}$ were ring-open polymerized by cationic catalyst to obtain alternating head-to-head (H-H) copolymers. For comparison, head-to-tail (H-T) copolymer $3_a$ was also prepared by free radical copolymerization of the corresponding monomers. The H-H copolymer exhibited minor differences in its $1_H% NMR and IR spectra, but in the $^{13}C$ NMR spectra significant differences were observed between the H-H and H-T copolymers. Glass transition temperature ($T_g$) of H-H copolymer was higher than that of the H-T copolymer, but thermal decomposition temperature of the H-H copolymer was lower than that of the H-T copolymer. Compounds $1_a$, $a_b$, and $1_c$, copolymerized well with styrene by cationic catalyst, but compound 1d failed to copolymerize with styrene. All of the H-H and H-T copolymers were soluble in common solvents and the inherent viscosities were in the range 0.2-0.4 dl/g.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.3001-3004
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• 2014

A series of hydroxyl-derivatized quaternized polymers were successfully synthesized by atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry), followed by quaternization reactions. ATRP was employed to synthesize poly(2-hydroxyethyl methacrylate) (PHEMA), followed by introduction of alkyne groups using pentynoic acid, leading to HEMA-Alkyne. 2-Azido-1-ethanol and 3-azido-1-propanol were combined with the HEMA-Alkyne backbone via click reaction, resulting in triazole-ring containing hydroxyl-derivatized polymers. Quaternization reactions with methyl iodide were conducted on the triazole ring of each polymer. Molecular weight, molecular weight distribution, and the degree of quaternization (DQ) were determined by gel permeation chromatography (GPC) and $^1H$ NMR spectroscopy. The average molecular weight ($M_n$) of the resulting polymers ranged from $5.9{\times}10^4$ to $1.05{\times}10^5g/mol$ depending on the molecular architecture. The molecular weight distribution was low ($M_w/M_n$ = 1.26-1.38). The transmission spectra of the 0.1 wt % aqueous solutions of the resulting quaternized polymers at 650 nm were measured as a function of temperature. Results showed that the upper critical solution temperature (UCST) could be finely controlled by the level of DQ.

• Macromolecular Research
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• 제15권2호
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• pp.142-146
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• 2007

Poly[(1-(9-carbazoly1)ethylene)-co-(3-cinnamoyloxyoctyl-9-carbazolyl)] ethylene (PVK-Cin) was prepared by tethering cinnamate pendants to a carbazole group via an octylene spacer. The photopatternability of the new PVK based-polymer was investigated using a photocrosslinking reaction under UV light illumination $(\lambda=254nm)$. Blends of the PVK-Cin and a soluble poly(phenylene vinylene) (CzEh-PPV) were employed to study the photocrosslinking behavior. Well resolved lithographic patterns were observed in these polymer systems. PVK-Cin produced a blue light emitting pattern both before and after the photocrosslinking reaction. The blends of PVK-Cin and CzEh-PPV also showed corresponding emissions at 398 and 525 (560) nm in the film state.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2694-2698
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• 2014

A multisegmented polystyrene (PS) with pH-cleavable ester and carbamate linkages was successfully synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry). ATRP was employed to synthesize polystyrene from hydroxyl-terminated initiator using CuBr/N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA) as the catalyst. The reaction of the resulting PS with sodium azide yielded the azido-terminated polymer. The hydroxyl group in the other end of the polymer was reacted with 4-nitrophenyl chloroformate (NPC), followed by reaction with propargylamine to produce an alkyne end group with a carbamate linkage. The PS with an alkyne group in one end and an azide group in the other end was then self-coupled in the presence of CuBr/2,2'-bipyridyl (bpy) in DMF to yield a desired multisegmented PS. Molecular weight and molecular weight distribution of the self-coupled polymer increased with time, as in the typical step-growth-type polymerization processes. Finally, we demonstrated that the ester and carbamate linkages of the multisegmented PS were hydrolyzed in the presence of HCl to yield individual PS chains.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2193-2199
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• 2012

A series of novel polytriazoleimides were prepared from various aromatic dianhydrides and a new kind of 1,2,3-triazole-containing aromatic diamine synthesized by the Cu (I)-catalyzed 1,3-dipolar cycloaddition reaction in DMAc, and characterized by FT-IR, $^1H$-NMR, XRD, DSC and TGA techniques. The results show the polytriazoleimides are soluble in most of strong polar solvents and have inherent viscosity values of 0.51-0.62 dL/g(DMAc). The polytriazoleimide films exhibit a tensile strength of 62.3-104.5 MPa and an elongation at breakage of 4.0-8.1%, a glass transition temperature ($T_g$) of $257-275^{\circ}C$, a decomposition temperature (at 5% weight loss) of $350-401^{\circ}C$ in $N_2$ atmosphere, and a dielectric constant of 2.47-3.01 at 10 MHz, which depend on the structure of the polymers. The polytriazoleimides perform good resistance to acid and alkali solution.

• 폴리머
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• 제34권2호
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• pp.137-143
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• 2010

불소 관능기인 perfluorocyclobutane(PFCB)기를 함유하는 설폰화된 부분 불소계 poly(biphenyleneco-sulfone)ether 공중합체(SPBS-X)를 제조하였다. 제조과정은 trifluorovinylether그룹을 양 말단에 포함하는 단량체의 합성, 고리화부가 반응형태의 열중합 그리고 후설폰화(post-sulfonation)의 3단계 합성과정을 통하였다. Trifluorovinylether그룹을 양 말단에 포함하는 biphenyl계와 sulfonyl계 단량체를 합성하였고, biphenyl계의 함량을 20 mol%에서 60 mol%까지 조절하면서 고리화부가 반응형태의 열중합을 통해 랜덤 공중합체가 얻어졌다(PBS-X). 후설폰화는 chlorosulfonic acid(CSA)를 사용하여 수행되었으며, 이를 통해 다양한 설폰화도를 가지는 고분자를 합성하였다. $^1H$-NMR, $^{19}F$-NMR 및 FT-IR 분석을 통하여, 제조된 화합물, 단량체 및 중합체들이 성공적으로 합성되었음을 확인하였다. 상온에서 CSA에 대해 설폰화 활성을 가지는 biphenyl기의 함량이 증가함에 따라 이온교환능력(IEC), 함수율 및 이온전도도가 증가하는 경향을 보였고, SPBS-60의 경우 넓은 온도범위(25~80 $^{\circ}C$)에서 Nafion$^{(R)}$-115보다 높은 이온전도도(80 $^{\circ}C$: 0.08 S/cm at RH 100%)를 나타내었다.

• 대한화학회지
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• 제28권5호
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• pp.284-292
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• 1984

치환체-E-arene-diazocyanides와 nitrosobenzenes의 (4+2) 고리첨가 반응의 배향성에 대한 치환기 및 산 촉매효과와 반응성을 예측하기 위하여 Diels-Alder 반응의 열 또는 촉매반응에 대하여 Frontier orbital theory (FMO)이론을 적용해서 CNDO/2 방법과 EHT-SPD 방법으로 고찰하였다. (1) 위 반응은 Hammett 식의 rho(${\rho}$)값이 양이므로 normal electron demand 반응형태를 가지며 4-FMO 및 Anh 방법이 실험적인 주 배향체와 일치함을 알았다. (2)전자끄는 기로 치환되면 dienophile의 HOMO, LUMO 궤도함수에너지가 낮아지고 반응성이 커지는 것을 알았다. (3)Lewis 산은 dienophile과 착물을 형성하고 dienophile의 LUMO계수를 정 반대로 분극시켜 주므로 주 배향제는 B형으로 예측된다. (4) diene HOMO-dienophile LUMO 상호작용의 안정화 에너지 (${\Delta}$E)와 Hammett식의 시그마 (${\sigma}$)값과의 그라프에서는 좋은 직선성을 보여 주었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권1호
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• pp.61-64
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• 2000

A series of 5-oxaproline peptide derivatives was synthesized and evaluated for its ability to inhibit the prolyl 4-hydroxylase in vitro. Structure-activity studies show that the 5-oxaproline sequences, prepared by the 1,3-dipolar cycloaddition of the C-methoxycarbonyl-N-mannosyl nitrone in the presence of the ethylene, are more active than the corresponding proline derivatives. Prolyl 4-hydroxylase belongs to a family of $Fe^{2+}-dependent$ dioxygenase, which catalyzes the formation of 4-hydroxyproline in collagens by the hydroxylation of proline residues in -Gly-Xaa-Pro-Gly- of procollagen chains. In this paper we discover the more selective N-Cbz-Gly-Phe-Pro-Gly-OEt $(K_m\;=\;520\;{\mu}M)$ sequences which are showed stronger binding than others in vitro. Therefore, we set out to investigate constrained tetrapeptide that was designed to mimic the proline structure of pep tides for the development of prolyl 4-hydroxylase inhibitor. From this result, we found that the most potent inhibitor is N-Dansyl-Gly-Phe-5-oxaPro-Gly-OEt $(K_i\;=\;1.6\;{\mu}M)$. This has prompted attempts to develop drugs which inhibit collagen synthesis. Prolyl 4-hydroxylase would seem a particularly suitable target for antifibrotic therapy.