• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.2111-2116
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• 2013

This paper reports substituent effects on the conformational changes in polyaniline (PAni) derivatives. PAni, poly-o-toluidine (POT), and poly-o-anisidine (POA) were formed by potentiodynamic electropolymerization in aqueous solution containing (+)-camphorsulfonic acid (CSA) as a dopant. UV-Vis spectroscopy and cyclic voltammetry measurements revealed that the methyl group showed a greater steric hindrance than the methoxy group. Further, the doping level decreased with increasing steric hindrance. The sign pattern of the circular dichroism (CD) bands for POA was opposite to that for PAni. However, no CD bands were observed in POT. The steric hindrance caused helical inversion, but at a high level of steric hindrance, the helical conformation could not be adopted, because of the reduced doping level. The reduced crystallinity was greatly affected by the decreased doping level. The steric effect influenced the polymer conformation and the doping level, thus determining the optical activity, morphology, and crystallinity of the PAni derivatives.

• Archives of Pharmacal Research
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• 제25권3호
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• pp.240-249
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• 2002

Dibenzyl-g-butyrolactone and 1,2,3,4-tetrahydro-2-naphthoic acid $\gamma$-lactone (TNL) derivatives were synthesized and evaluated for cytotoxic activity against some cancer cell lines. It was found that TNL derivatives with a shorter distance between C-4 in ring A and C'-2 in ring C were more cytotoxic, while dibenzyl-${\gamma}$-butyrolactones with a longer one were nearly inactive. In TNL series, presence of 3,4-dioxy group in ring A and 2-methoxy group in ring C was essential for the enhancement of the activity.

• 약학회지
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• 제32권2호
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• pp.125-128
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• 1988

Geranylation of some synthetic and natural flavones have yielded cytotoxic products against L1210 coll; 5,2´-dihydroxy-6,7,8-trimethoxy-6´-geranyloxyflavone 4$(8.5{\mu}g/ml)$, 5,6-dihydroxy-7-gerenyloxyflavone 9$(2.3{\mu}g/ml)$. 2 has showed the same range of cytotoxicity as the starting material, 5,2´-dihydroxy-6,7,8-trimethoxy-6´-benzyloxyflavone$(17.0{\mu}g/ml)$. The cytotoxicity of 4 was lower than its starting substance, 5,2´,6´-trihydroxy-6,7,8-trimethoxyflavone $(4.5{\mu}g/ml)$. On geranylating 5,6,7-trihydroxyflavone(baicalein, $15.0{\mu}g/ml$) the cytotoxic activity has been strongly potentiated($2.3{\mu}g/ml$ of 9). The presence of at least a free hydroxy group in B-ring of Skullkapflavone II-type flavones. was essential for a high activity. A larger RD-group than methoxy in the B-ring has weakened the activity. The cytotoxicities of baicalein series could not be correlated to their structures.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
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• pp.605-605
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• 2003

Novel silane coupling agents containing hydrophobic phenyl group 3-(3-methoxy-4-methacryloyloxyphenyl) propyl-trimethoxysilane(p-MPS), -triisocyanatesilane (p-MBI), -trichlorosilane (p-MBC) were synthesized. The bonding durability of these silanes against water immersion and thermal stress was investigated. 3-methacryloyloxypropyltrimethoxysilane (3-MPG) was used as a control. The glass modified with those silanes at a concentration of 2wt％ were kept for 3 minutes at $120^{\circ}C$, and then were bonded to the heaped metal with self-cured resin composite.(omitted)

• Archives of Pharmacal Research
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• 제22권2호
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• pp.184-188
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• 1999

A series of 4-amino Capsaincin anallogs 15, 17 and 19 were prepared to investigate the bioisosteric effect of 4-amino group, and all these compounds exhibited moderate or weak potency from their analgesic test. From our previous results and others, 4-hydroxyl group as well as 3-methoxy substituent could be crucial for high analgesic activity. This biological results also shows that the activity is sensitive to alkyl chain length in hydrophobic region and the phenylacetic amides 19 are more active than the corresponding urea derivatives 17.

• Macromolecular Research
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• 제15권3호
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• pp.216-220
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• 2007

A new polyfluorene-based copolymer having 2-ethylhexyloxy-5-methoxy-l,4-phenylene as an electron donating group and 2,5-diphenyl-oxadiazole as an electron withdrawing group was synthesized by the Suzuki coupling reaction. The obtained copolymer was characterized by $^1H-NMR,\;^{13}C-NMR$, and IR-spectroscopy. The weight average molecular weight ($M_w$) of the obtained polymer was 18,600 with a polydispersity index of 1.5. The maximum photoluminescence of the solution and film of the polymer was observed at 453 nm and 456 nm, respectively. A double-layer device with the configuration, ITO/PEDOT/copolymer/Al, emitted blue light at 460 nm.

• 농약과학회지
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• 제2권3호
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• pp.64-69
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• 1998

기질(S) 화합물로 30종의 5,6-dihydro-2-trifluoromethyl-1,4-oxathiin carboxanilide 유도체들을 합성하고 벼 잎집무늬 마름병균(Rhizoctonia solani)과 밀 붉은 녹병균(Puccinia recondita)에 대한 항균활성(in vivo) 값($pI_{50}$)을 측정하였다. (S)는 잘록병균보다 밀 붉은녹병균에 대하여 보다 큰 항균활성을 나타내었으며 두 종의 균에 대하여 3-methoxy, 11, 3-iso-propyloxy, 13 및 3-iso-propyl 치환체, 25가 제일 큰 활성을 보였다. 그리고 치환(X)-phenylcarbamoyl group의 변화에 따른 물리-화학 파라미터와 항균활성($pI_{50}$)으로부터 구조-활성관계(SAR)를 검토 한 결과, 벼 잎집무늬 마름병균에 대하여는 공명효과에 따른 전자밀게(R<0)의 소수성이 큰(${\pi}>0$) m-alkyl 치환기(X)가, 그리고 밀 붉은녹병균에 대하여는 분자 분극율(Sp.Pol.)과 분자의 음하전(ABSQ<0)을 위시하여 HOMO에너지(e.v.)가 클수록(HOMO<0) 높은 항균활성을 나타내었다. 또한, 전하-조절 반응에 의한 수용체-(S)간의 상호작용과 높은 활성발현 조건들이 검토되었다.

• 한국세라믹학회지
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• 제35권5호
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• pp.421-428
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• 1998

순수 HAC/PVA 계 및 epoxy 수지와 urethane이 첨가된 HAC/PVA 계 MDF 시멘트 복합재료에 서로 다른 관능기를 갖는 3종류의 silane coupling agent를 첨가하여 강도 및 수분안정성에 대한 영향을 살펴보고 기공율 분석을 통해 미세구조와 강도의 관계를 살펴보았다. Silane의 관능기에 따라 각각의 MDF 시멘트 복합재료의 강도 및 수분안정성 향상에 대한 효과가 다른 것을 알 수 있었다. 순수 PVA 메트릭스의 경우에 대해서는 vinyl 기를 갖는 silane이 효과적인 영향을 나타내었으며 epoxy수지가 첨가된 MDF 시멘트에 대해서는 epoxy-methoxy 기를 갖는 silane이, 그리고 urethane이 첨가된 MDF 시멘트에 대해서는 diamine 기의 silane이 효과적이었다. Silane의 첨가량에 따라서는 urethane이 첨가된 MDF 시멘트 복합재료의 경우, diamine 기의 silane이 많이 첨가될수록 수분안정성이 향상되었으며 특히 2wt%의 silane을 첨가하고 wqrm press를 이용하여 성형하였을 때 건조 강도는 약 20% 향상되었으며 습윤강도는 40~70%까지 크게 향상되었다. 이는 기공율과 밀접한 관계가 있음을 알 수 있었다. Epoxy 수지가 첨가된 MDF 시멘트의 경우에서도 2wt%의 silane 첨가까지는 그 첨갈향이 많아질수록 강도가 향상되는 것을 알 수 있었지만 과량의 silane(4wt%)이 첨가될 경우에서는 오히려 특성저하가 나타났다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
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• pp.173-176
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• 2006

Pyrolysis-gas chromatography (Py-GC) in the presence of organic alkali of tetrabutylammonium hydroxide (TBAH) was applied to characterize the polyphenol fragments with a carbonyl group causing different magnitude of photo-yellowing in chemithermomechanical pulp (CTMP) papers. Two different origin of CTMP papers prepared from different individuals of Eucalyptus globulus trees showing high and low yellowing after photo-irradiation was compared before photo-irradiation. As a result, 7 peaks assigned to a series of phenol compounds with a carbonyl group, derived mainly from lignin, gave significant amount of phenol compounds with a carbonyl group for the paper sample of latent high yellowing, i.e., butoxy-and syringaldehyde, butoxy-and syringylacetone, butoxy-acetoguaiacone, butoxy-acetosyringone, butoxy-acetoethylsyringone, 3-methoxy-4-butoxy butyl ester, and 3,5-dimethoxy-4-butoxy butyl ester, using Py-GC/mass spectrometry (MS). The Py-GC method combined with TBAH successfully characterized polyphenol fragments with a carbonyl group causing differ high photo-yellowing in CTMP papers using a microgram order of samples.

• Archives of Pharmacal Research
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• 제19권1호
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• pp.6-11
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• 1996

The trichothecenes are sesquiterpenoid mycotoxins characterized by the 12,13-epoxytrichothec-9-ene ring system. We have tested cytotoxicity of several naturally-occurring or synthesized trichothecenes against human solid tumor cell lines. Among them, trichothecin(I) and $4-\beta$-Acetoxy-12,13-epoxytrichothec-9-ene (trichodermin, II) exhibited highly cytotoxic activities. 4-.betha.-Hydroxy-12,13-epoxytrichothec-9-ene (trichodermol, III) and $4-\beta$-Methoxy-12,13-epoxytrichothec-9-ene (IV) had mild cytotoxicities. But 12,13-Epoxytrichothec-9-ene-4-one (V) and $4-\beta$-Hydroxy-12,13-epoxytrichothec-9-ene(VI) had no cytotoxicities up to 10 $\mug/ml$. And in the tested cell lines, HCT15 colon cancer cell line was the most sensitive to all tested trichothecenes.