• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.793-797
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• 2010

A series of 2-aminothiazoles derivatives have been synthesized and tested for in vitro antibacterial activity on different microorganisms. Syntheses have been carried out following simple methodology in excellent isolated yields. The structure and purity of the original compounds were confirmed by IR, NMR, Mass spectroscopy, and elemental analysis. All compounds were tested for antibacterial activity against S. aureus, S. pyogenes, E. coli, P. aeruginosa, S. typhi and V. parahaemolyticus. These preliminary results indicate that some of compounds are exhibiting good activity.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3530-3538
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• 2010

In this study 1-[4-(2-methoxy benzyl)-6-aryl-pyridazin-3(2H)-ylidene] hydrazines were used for the synthesis of new heterocyclic systems such as thiazolidine, phthalazine, pyrazolo, tetrazolo, hydrazide and new pyridazine derivatives to explore the effect of silver nanoparticles on their biological activity efficiency. Structures of the new heterocycles were characterized by the aid of several analytical techniques including; $^1H$-NMR, FTIR and mass spectra. Silver nanoparticles were synthesized by a simple methodology and the formation of silver nanoparticles was confirmed by transmission electron microscopy (TEM) and UV studies. Most of the new prepared heterocycles were evaluated in vitro as new antimicrobial agents. Combination effects of the silver nanoparticles on the antimicrobial activity of the new heterocycles were investigated using the disk diffusion method. Compound 10a exhibited the strongest enhancing effect of silver nanoparticles solution against Aspergillus flavus and Candida albicans.

• The Korean Journal of Ceramics
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• 제6권4호
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• pp.370-379
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• 2000

Simple ways to build up mixed-metal molecules which can act as potential single-source precursors to multimetallic oxides are reviewed. Emphasis is given to Lewis acid-base reactions between metal alkoxides M(OR)/sub n/, and between metal alkoxides and more accessible oxide precursors, carboxylates M(O₂CR)/sub n/ and β-diketonates M(β-dik)/sub n/. Characterization of the precursors is achieved in the solid state (single crystal X-ray diffraction, FT-IR) and by multinuclear NMR in solution. The reactions proceed toward the formation of aggregates in which the different metals display their usual coordinations numbers, often six for transition metals, as shown. Strategies for fixing the stoichiometry between the metals are developed. The reactivity of the MM species (dissociation, effects of chemical modifiers, of other metallic species, hydrolytic or non-hydrolytic condensation, etc.) will be indicated. Transformations into oxides are illustrated on precursors for titanates or niobates.

• Natural Product Sciences
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• 제22권2호
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• pp.117-121
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• 2016

On the phytochemical investigation of a 70% ethanol extract of the fruits of Opuntia ficus-indica, (Cacataceae), we could result in the isolation of thirteen phenolic compounds including seven flavonoids (1 - 9) and four simple phenolic glycosides (10 - 13) by column chromatographic methods. Among the isolated compounds, picein (11), androsin (12), and $1-O-feruloyl-{\beta}-{\small{D}}-glucopyranoside$ (13) were isolated for the first time from O. ficus-indica; additionally, this is the first report $benzyl-O-{\beta}-{\small{D}}-glucopyranoside$ (10) from the genus Opuntia. The structures of the compounds were determined by spectral data analysis which included 1D, 2D NMR spectrum and ESIMS.

• Natural Product Sciences
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• 제22권1호
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• pp.30-34
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• 2016

A simple and rapid method based on proton nuclear magnetic resonance spectroscopy was developed for determination of trans-anethole content in fennel essential oil. Spectra of pure trans-anethole, of the pure essential oil of fennel, and of the pure oil of fennel with thymol internal standard were recorded. The signal of $H-1^/$ was used for quantification of trans-anethole. This proton signal is well separated in the proton magnetic resonance spectrum of the compound. No reference compound is needed and cheap internal standard was used. The results obtained from spectroscopic analysis were compared with those obtained by gas chromatography. Additionally, the developed method was used for determination of the type of vegetable oil used as a carrier in commercial products, which cannot be quantified as such by gas chromatography. This study demonstrates the application of proton nuclear magnetic resonance spectroscopy as a quality control method for estimation of essential oil components.

• 지질공학
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• 제29권4호
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• pp.579-598
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• 2019

강원도 태백산국립공원 구역에 인접한 동해폐탄광으로부터 발생하는 산성광산배수(AMD)에 대하여 수질오염과 하상퇴적물 내 Fe, Al의 거동특성을 화학분석, XRD, 적외선분광분석(IR), 핵자기공명분석(²⁷Al NMR)을 이용하여 연구하였다. 산성광산배수의 수질은 pH와 용존이온의 침전에 따라서 변화하며, 포화지수 계산에 따르면 대부분 다양한 철, 알루미늄 수산화광물종에 과포화되어 있다. 하상의 적갈색 침전물은 슈베르트마나이트, 페리하이드라이트와 침철석으로 구성된다. 백색침전물은 대부분 알루미늄광물인 배스알루미나이트로 구성되는데, 이것의 결정도는 매우 낮다. 배스알루미나이트에서는 Al-중합체 Al₁₃-Tridecamer가 소량으로 함유되어 있다. 동해폐탄광의 산성광산배수를 저감하기 위해서는 단순한 저류조 운영보다는 적극적인 제거법을 적용하여 철, 알루미늄 광물의 침전과 용해도를 조절할 필요가 있다.

• Journal of Applied Biological Chemistry
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• 제63권4호
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• pp.407-412
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• 2020

Ulmus parvifolia 잎의 약리학적 지표 성분을 제시하기 위해 간단하고 신뢰할 수 있는 HPLC 분석방법을 개발하였다. 지표 성분들은 NMR 및 UPLC-QTof-MS 분석에 의해 neochlorogenic acid (trans-5-O-caffeoylquinic acid, 5-CQA)과 chlorogenic acid (trans-3-O-caffeoylquinic acid, 3-CQA)로 구조 동정 되었다. HPLC를 이용하여 두개 화합물을 포함한 잎 추출물의 정성/정량 분석 방법을 평가하였다. 잎 30% 에탄올 추출물과 지표 성분의 안정성 테스트는 6개월 동안 평가되었다. 그러나 안정성 조사 기간 동안 추출물과 지표 성분들 각각의 함량에 대한 유의한 변화는 관찰되지 않았다.

• Restorative Dentistry and Endodontics
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• 제25권2호
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• pp.272-288
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• 2000

수산화칼슘은 여러 약리작용으로 인해 근관소독제로 널리 사용되고 있는 약제이다. 근관 내에 수산화칼슘을 투약한 후 gutta-percha와 더불어 산화아연-유지놀계 근관시멘트로 근관을 충전하는 경우 근관시멘트의 물성에 변화가 있다는 보고가 있다. 따라서 본 연구에서는 수산화칼슘과 산화아연-유지놀 간의 반응에 의해 생성되는 수산화칼슘-유지놀 화합물의 반응성을 확인하기 위하여 수산화칼슘, 유지놀, 산화아연-유지놀, 수산화칼슘-유지놀 및 수산화칼슘-산화아연-유지놀 화합물을 XRD, FT-IR spectrophotometer 및 FT-NMR spectrometer로 분석하여 다음과 같은 결과를 얻었다. 1. 수산화칼슘과 산화아연-유지놀 간의 반응으로 생성된 화합물은 다음과 같았다. 2. 수산화칼슘은 유지놀과 화학결합(이온결합)을 하는 것으로 나타났다. 3. $Ca^{2+}$과 유지놀 사이의 결합은 단순 이온결합이다. 따라서 수산화칼슘-산화아연유지놀 화합물은 중화반응에서 생기거나 외부에서 유입된 물이 존재시 쉽게 이온화되어 물리적 성질이 저하될 것으로 생각된다.

• Macromolecular Research
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• 제15권6호
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• pp.541-546
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• 2007

The combination of atom transfer radical polymerization (ATRP) and click chemistry was employed for the efficient preparation of well-defined block copolymers. Bromo terminated poly(methyl acrylate) (pMA-Br) was prepared by an ATRP initiator, ethyl-2-bromoisobutyrate (EBiB). Subsequently, the bromine chain end of pMA-Br was converted to an azide group by simple nucleophilic substitution reaction. ${\alpha}-Alkyn-{\omega}-bromo-functionalized$ polystyrene was also synthesized by ATRP using the alkyn-functionalized initiator, propargyl-2-bromoisobutyrate (PgBiB). In both cases, the conversion was limited to a low level to ensure a high degree of chain end functionality. Then the coupling reaction between the azide end group in $pMA-N_3$ and alkyn-functionalized PgBiB-pSt was performed by Cu(I)catalysis. This coupling reaction was monitored by gel permeation chromatography (GPC). The synthesized block copolymer was characterized by FT-IR, $^1H-NMR$ spectroscopy and $^1H-^1H$ COSY correlation spectroscopy.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3805-3810
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• 2013

The surface modification of silica particles (SPs) was systemically conducted by the treatment of 0.1-10 wt % phenylsilanetriol (PST) on the basis of SPs used through two step processes: 1) the PST coating of SPs via evaporation under reduced pressure and 2) their thermal condensation leading to Si-O-Si bond formation via heating at $130^{\circ}C$. The evaluation of the modified SPs was conducted by the simple floating test on water and the measurement of the contact angle (CA) of water droplet on the 2-dimensional layer of modified SPs on slide glass. When PST was used about 2 wt % or above on the basis of SPs (about average size: 50 nm) used, the modified SPs were fully floated on the water and all dispersed into upper organic solvent layer after a shaking with the mixture of the water and benzene, indicating that the modified SPs have hydrophobic properties. The modified SPs were characterized by $^{29}Si$ MAS NMR and physicochemical properties including SEM, TEM, BET, adsorption/desorption isotherms, etc. were measured and compared each other in details. This research demonstrates that the organosilanetriol is a good modifier applicable for the surface modification of inorganic oxide particles using a low amount of modifier on the basis of oxide particles used.