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실란 개질제가 실리카충전고무 컴파운드에 미치는 영향

  • Kim, Gwang-Je
    • Rubber Technology
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    • v.9 no.1
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    • pp.1-12
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    • 2008
  • Effects of silane modifier, bis(triethoxysilylpropyl) tetrasulfide (TESPT(S4)) and bis(triethoxysilylpropyl) disulfide (TESPD(S2)), on silica filled compound were investigated upon processability, dynamic, mechanical, heat build-up, blowout properties, and silica dispersion in natural rubber (NR). The temperature of the S2 treated silica compound generated higher than that of the S4 treated compound during internal mixer compounding. The shear viscosity of the S2 compound exhibited lower than that of the S4 compound and the viscosity measured in dynamic mode was close to each other. The elongation modulus of the S2 compound exhibited lower than that of the S4; however, the tear resistance strength of the S2 compound exhibited higher than that of the S4 compound. The loss tan$\delta$ values of the S2 compound exhibited higher than those of the S4 at room temperature. The augmentation of the test temperature lowered the tan$\delta$ values of each compound, which results in close tan$\delta$ values to each other at $100^{\circ}C$. The S2 compound deformed less than the S4 compound, and the blowout time of each compound was close to each other. The S2 compound generated more heat build-up than the S4 compound. The abrasion loss of the S2 compound was less than that of the S4 compound. The size of the silica agglomerate reduced on both S4 and S2 compounds upon vulcanization. The addition of the bifunctional silanes (S2 and S4) on silica filled NR compound improved the processability of each compound and their effects were more significant on the S2 compound than the S4 compound. After vulcanization the silica agglomerate size of each compound reduced compared with before vulcanization.

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Synthesis of Some New Condensed Pyrimidine Derivatives

  • Mohamed, Enaiat K.;Shehab, Wesam S.
    • Journal of the Korean Chemical Society
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    • v.55 no.6
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    • pp.988-993
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    • 2011
  • Cyclodehydration of 6-amino-5-cyano pyrimidine derivative (2) afforded pyrimidoisoindole derivatives (3). Compound (3) reacted with carbethoxymethylene derivative to give pyridopyrimidine derivatives (5a,b). Compound (3) was also reacted with formamide to give the corresponding pyrimidopyrimdine derivatives (6) that condensed with benzaldehyde to give Schiff's base (7). Refluxing of compound (3) with triethyl orthoformate afforded compound (8) that cyclized with ammonium hydroxide giving the same compound (6). Compound (8) cyclized with hydrazine hydrate giving compound (9) which also cyclized with triethyl orthoformate affording compound (10). Diazotization of compound (3) led to the formation of triazinopyrimidine derivative (11). Cyclization of compound (11) upon treatment with hydrazine hydrate afforded compound (12). Compound (15) was prepared from reaction of compound (3) and ethylenediamine in presence of carbon disulfide. The behaviour of compound (15) toward benzoyl chloride, triethyl orthoformate, nitrous acid and/or carbon disulfide was also described. All proposed structures were supported by elemental analyses, spectroscopic data and some of the new products showed antimicrobial activity.

Identification of Biologically Active Compounds from Panax ginseng C. A. Meyer (한국산 인삼의 polyphenol 화합물의 생리활성 효과)

  • Choi, Hee-Jin;Zhang, Yun-Bin;An, Bong-Jeon;Choi, Cheong
    • Korean Journal of Food Science and Technology
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    • v.34 no.3
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    • pp.493-497
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    • 2002
  • The polyphenol compounds of Korea ginseng radix were extracted with 60% acetone for 4 days at room temperature and purified using Sephadex LH-20 column chromatography, MCI gel column chromatography, Bondapak $C_{18}$, column chromatography, TLC and HPLC. As a result in three compounds were isolated from Korean ginseng. In the inhibitory activities of angiotensin converting enzyme, compound Ⅱ showed the highest value of 31.86% inhibition at 157 ppm. Compound I showed 19.4% inhibition at 157 ppm. In the inhibitory activities of xanthine oxidase, compound I, II showed complete inhibition at 666 ppm but compound III didn't have inhibitory activity. In the inhibitory activities of tyrosninase, compound III showed 6.1% inhibition at 300 ppm and 28.6% at 400 ppm.

Pharmacokinetics of ginsenoside Rb1 and its metabolite compound K after oral administration of Korean Red Ginseng extract

  • Kim, Hyung-Ki
    • Journal of Ginseng Research
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    • v.37 no.4
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    • pp.451-456
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    • 2013
  • Compound K is a major metabolite of ginsenoside Rb1, which has various pharmacological activities in vivo and in vitro. However, previous studies have focused on the pharmacokinetics of a single metabolite or the parent compound and have not described the pharmacokinetics of both compounds in humans. To investigate the pharmacokinetics of ginsenoside Rb1 and compound K, we performed an open-label, single-oral dose pharmacokinetic study using Korean Red Ginseng extract. We enrolled 10 healthy Korean male volunteers in this study. Serial blood samples were collected during 36 h after Korean Red Ginseng extract administration to determine plasma concentrations of ginsenoside Rb1 and compound K. The mean maximum plasma concentration of compound K was $8.35{\pm}3.19$ ng/mL, which was significantly higher than that of ginsenoside Rb1 ($3.94{\pm}1.97$ ng/mL). The half-life of compound K was 7 times shorter than that of ginsenoside Rb1. These results suggest that the pharmacokinetics, especially absorption, of compound K are not influenced by the pharmacokinetics of its parent compound, except the time to reach the maximum plasma concentration The delayed absorption of compound K support the evidence that the intestinal microflora play an important role in the transformation of ginsenoside Rb1 to compound K.

Chemical Structure of Polyphenol Isolated from Korean Pear (Pyrus pyrifolia Nakai) (한국산 배 (Pyrus pyrifolia Nakai)로부터 polyphenol 화합물의 구조결정)

  • Zhang, Yun-Bin;Choi, Hee-Jin;Han, Ho-Suk;Park, Jung-Hye;Son, Jun-Ho;Bae, Jong-Ho;Seung, Tae-Su;An, Bong-Jeun;Kim, Hyun-Gu;Choi, Cheong
    • Korean Journal of Food Science and Technology
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    • v.35 no.5
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    • pp.959-967
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    • 2003
  • The polyphenol compounds of Korean pears were extracted with 60% acetone for 4 days at room temperature and purified using Sephadex LH-20 column chromatography, MCI gel column chromatography, Bondapak $C_{18}$ column chromatography, TLC, and HPLC. As a result, three compounds were isolated. The chemical structures of each compound were determined and identified using NMR, FAM-mass, and FT-IR. The compounds were confirmed as (+)-catechin (compound A), (+)-gallocatechin (compound B), (-)-epigallocatechin (compound C), and procyanidin B-3-3-o-gallate (compound D).

A Study on the Handling of 'Compound Particles' in the Teaching of Korean Particle Combination (한국어 조사 결합 교육에서의 복합조사 처리에 대한 고찰)

  • Han, Yunjung
    • Journal of Korean language education
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    • v.28 no.3
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    • pp.153-180
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    • 2017
  • This research examined compound particles, which have not been properly addressed in existing studies on particle combination education, from the perspective of Korean language education as a second language. First, existing research was examined with the understanding of the issue that there is a lack of discussion in existing studies on the education method of either including the compound particle in particle combination or excluding it all together. In the next chapter, an examination was made on the concept and usage of terminology for compound particles in the field of Korean linguistics. Following a summary of this information, a review was made on the list of compound particles established in Korean linguistics. Thus, seven compound particles were identified for Korean language education considering discriminant standard and educational effectiveness from the perspective of Korean language education. The researcher proposes that the compound particle should be taught as an extension of particle combination education and that its concept should be clearly outlined as a direction for future education.

The chemical structure of polyphenols isolated from cacao bean and their inhibitory effect on ACE (Cacao bean으로부터 분리된 polyphenol 성분의 화학구조분석과 ACE 저해효과)

  • Chang, Young-Youl;Yim, Moo-Hyun;Lee, Man-Chong
    • Applied Biological Chemistry
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    • v.41 no.1
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    • pp.110-117
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    • 1998
  • Seven kinds of polyphenol compounds having ACE activities were isolated and purified by Sephadex LH-20, MCI-gel CHP-20, ${\um}-Bondapak\;C_{18}$ and Fuji-gel ODS $G_3$ sucessively from cacao bean(Ghana). The chemical structures of each compound were determined and identified using analyzers such as $^1H-NMR$, $^{13}C-NMR$, IR, MS, polarimeter and Elemental Analysis. Inhibition effects of isolated polyphenols on angiotensin converting enzyme (concerned with hypertension) were also observed. The results obtained were as follows,; The compounds isolated and identified were confirmed and determined as compound 1 [(+)-catechin], compound 2 [(-)-epicatechin], compound 3 [procyanidin B-1 : (-)-epicatechin-$(4{\beta}{\rightarrow}8)$-(+)catechin], compound 4 [procyanidin B-2 : (-)-epicatechin-$(4{\beta}{\rightarrow}8)$-(-)-epicatechin], compound 5 [procyanidin B-7 : (-)-epicatechin-$(4{\beta}{\rightarrow}6)$-(+)-catechin], campound 6 (procyanidin B-2,3,3'-O -digallate), compound 7 [cinnamtannin A-2 : (-)-epicatechin-$(4{\beta}{\rightarrow}8)$-(-)-epicatechin-$(4{\beta}{\rightarrow}8)$-(-)-epicatechin-$(4{\beta}{\rightarrow}8)$-(-)-epicatechin]. In the inhibition effect on ACE, procyanidin B-2,3,3'-O-digallate (compound 6) showed a higher value of 94.6% for ACE in $100\;{\um}M$ than other compounds such as (+)-catechin (compound 1), (-)-epicatechin (compound 2), procyanidin B-1 (compound 3), procyanidin B-2 (compound 4), procyanidin B-7 (compound 5) and cinnamtannin A-2 (compound 7) showing 67.9%, 61.9%, 88.6%, 82.5%, 72.2% and 82.3% for ACE, respectively. Inhibition of $4{\beta}{\rightarrow}8$ in coupling bond on the ACE enzyme was more effective than that of $4{\beta}{\rightarrow}6$. Procyanidin containing gallate inhibited more effectively than those containing not any. It was also observed that a lot of hydroxy group in the compounds increased the inhibitory effect.

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The Characteristics of Compound Layers Formed during Plasma Nitrocarburising in Pure Iron (플라즈마 침질탄화처리된 순철의 화합물층 특성)

  • Cho, H.S.;Lee, S.Y.;Bell, T.
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.3
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    • pp.143-150
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    • 2000
  • Ferritic plasma nitrocarburising was performed on pure iron using a modified DC plasma unit. This investigation was carried out with various gas compositions which consisted of nitrogen, hydrogen and carbon monoxide gases, and various gas pressures for 3 hours at $570^{\circ}C$. After treatment, the different cooling rates(slow cooling and fast cooling) were used to investigate its effect on the structure of the compound layer. The ${\varepsilon}$ phase occupied the outer part of the compound layer and ${\gamma}^{\prime}$ phase existed between the ${\varepsilon}$ phase and the diffusion zone. The gas composition of the atmosphere influenced the constitution of the compound layer produced, i.e. high nitrogen contents were essential for the production of ${\varepsilon}$ phase compound layer. It was found that with increasing carbon content in the gas mixture the compound layer thickness increased up to 10%. In the gas pressure around 3 mbar, the compound layer characteristics were slightly effected by gas pressure. However, in the low gas pressure and high gas pressure, the compound layer characteristics were significantly changed. The constitution of the compound layer was altered by varying the cooling rate. A large amount of ${\gamma}^{\prime}$ phase was transformed from the ${\varepsilon}$ phase during slow cooling.

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새로운 Quinolone 항균제 개발 연구

  • 함원훈
    • Proceedings of the Korean Society of Applied Pharmacology
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    • pp.118-118
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    • 1993
  • 퀴놀론 모핵의 합성은 기존에 알려진 합성 방법인 Could-Jacobs방법과 Bayer방법에 의해서 Intermediate로 사용된 7-chloro-1-ethyl-6-fluoro-1, 4-dihydro-4-oxoquinoline-3-carboxylic acid와 1-cyclopropyl-7-chloro-6-Fluoro-1,4-dihydro-4-oxoquinolne-3-carboxylic acid를 합성하였다. Heteroaromatic tin compound는 furan, thiophene, 3-bromopyridine, 2-fluoropyridine에 n-BuLi을 사용하여 metallation 한후 electrophile로 tributyltin chloride를 사용하여 2-tributylstannofuran, 2-tributylst-annothiophene, 3-tributylstannopyridine, 2- fluoro-2-tributylstannop-yridine을 합성할 수 있었다. 이상의 Intermediate와 tin compounds를 p-alladium 촉매하에서 반응시켜 1-ethyl-7-(2-furanyl)-6-fluoro-1,4-dihy-dro-4-oxo-3-quinoline-carboxylic acid (compound 3), 1-ethyl-7-(2-th-iophenyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinol in carboxylic acid(compound 5), 1-ethyl-7-(3-pyridinyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinoline carboxylic acid (compound 7), 1-ethyl-7-(2-fluoro-3-pyrid-nyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinoline carboxylic acid (compound 9), 1-cyclopropyl-7-(2-furanyl) -6-fluoro-1,4-dihydro-4-oxo-3-quinoline carboxylic acid (compound 4), 1-cyclopropyl-7-(2-thiophenyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinoline carboxylic acid (compound 6) ,1-cyclopropyl-7-(3-pyridinyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinoline carboxylic acid (compound 8), 1-cyclopropyl-7-(2-fluoro-3-pyridinyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinoline carboxylic acid (compound 10)를 합성하였다.

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Structural Control of the Compound Layers formed during Nitrocarburising in NH3-Air-C3H8 Atmospheres (NH3-Air-C3H8 분위기에서 Nitrocarburisng시 형성된 Compound Layer의 조직제어)

  • Kim, Y.H.;Choi, K.W.
    • Journal of the Korean Society for Heat Treatment
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    • v.8 no.4
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    • pp.289-301
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    • 1995
  • The effect of Air/$C_3H_8$ gas addition on the compound layer growth of steels nitrocarburised in $NH_3+Air+C_3H_8$ mixed gas atmospheres was investigated. It is considered that amount of residual $NH_3$ was varied according to alternation of Air/$C_3H_8$ mixing ratio and volume content. The compound layer formed from nitrocarburising was composed of ${\varepsilon}-Fe_{2-3}$(C, N) and ${\gamma}^{\prime}-Fe_4$(C, N). According as Air/$C_3H_8$ mixing ratio increased, the superficial content of ${\gamma}^{\prime}-Fe_4$(C, N) within the compound layer was increased, at the same time the growth rate of compound layer and porous layer was increased. In the case of alloy steel at the fixed gas composition, the growth rate of compound layer and porous layer was worse than carbon steel and compound layer phase composition structure primarily consisted of E phase. As the carbon content of materials was increasing in the given gas atmospheres, the growth rate of compound layer and porous layer was increased and the superficial content of ${\varepsilon}-Fe_{2-3}$(C, N) within the compound layer was increased.

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