• 대한화학회지
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• 제55권6호
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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.

• Journal of Electrochemical Science and Technology
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• 제12권1호
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• pp.112-125
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• 2021

The new emerging "High entropy materials" attract the attention of the scientific society because of their simpler structure and spectacular applications in many fields. A novel nanocrystalline high entropy (Be,Mg,Ca,Sr,Zn,Ni)3O4 oxide has been successfully synthesized through mechanochemical treatment followed by sintering and air quenching. The present research work focuses on the possibility of single-phase formation in the aforementioned high entropy oxide despite the great difference in the atomic sizes of reactant alkaline earth and 3d transition metal oxides. Structural properties of (Be,Mg,Ca,Sr,Zn,Ni)3O4 high entropy oxide were explored by confirmation of its single-phase Fd-3m spinel structure by x-ray diffraction (XRD). Further, nanocrystalline nature and morphology were analyzed by scanning electron microscopy (SEM). Among thermal properties, thermogravimetric analysis (TGA) revealed that the (Be,Mg,Ca,Sr,Zn,Ni)3O4 high entropy oxide is thermally stable up to a temperature of 1200℃. Whereas phase evolution in (Be,Mg,Ca,Sr,Zn,Ni)3O4 high entropy oxide before and after sintering was analyzed through differential scanning calorimetry (DSC). Electrochemical studies of (Be,Mg,Ca,Sr,Zn,Ni)3O4 high entropy oxide consists of a comparison of thermodynamic and kinetic parameters of water and hydrazine hydrate oxidation. Values of activation energy for water oxidation (9.31 kJ mol-1) and hydrazine hydrate oxidation (13.93 kJ mol-1) reveal that (Be,Mg,Ca,Sr,Zn,Ni)3O4 high entropy oxide is catalytically more active towards water oxidation as compared to that of hydrazine hydrate oxidation. Electrochemical impedance spectroscopy is also performed to get insight into the kinetics of both types of reactions.

• Carbon letters
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• 제24권
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• pp.1-9
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• 2017

We studied the basic properties and fabrication of reduced graphene oxide (rGO) prepared using eco-friendly reduction agents in the graphene solution process. Hydrazine is generally used to reduce graphene oxide (GO), which results in polluting emissions as well as fixed nitrogen functional groups on different defects in the graphene sheets. To replace hydrazine, we developed eco-friendly reduction agents with similar or better reducing properties, and selected of them for further analysis. In this study, GO layers were produced from graphite flakes using a modified Hummer's method, and rGO layers were reduced using hydrazine hydrate, L-ascorbic acid, and gluconic acid. We measured the particle sizes and the dispersion stabilities in the rGO dispersed solvents for the three agents and analyzed the structural, electrical, and optical properties of the rGO films. The results showed that the degree of reduction was in the order L-ascorbic acid ${\geq}$ hydrazine > glucose. GO reduced using L-ascorbic acid had a sheet resistance of $121k{\Omega}/sq$, while that reduced using gluconic acid showed worse electrical properties than the other two reduction agents. Therefore, L-ascorbic acid is the most suitable eco-friendly reduction agent that can be substituted for hydrazine.

• Bulletin of the Korean Chemical Society
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• 제23권12호
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• pp.1715-1718
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• 2002

Treatment of ethyl 5-hydroxy-3,4-diphenylthieno[2,3-c]pyridazine-6-carboxylate (1a) with hydrazine hydrate in ethanol gave the carbohydrazide 2,. Some derivatives of the latter compound have been synthesized. Also, 6-acetyl-3,4-diphenyl-5-hydroxythieno[2.3-c]pyridazine (1b) was subjected to some reactions to produce other new thienopyridazine derivatives.

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.2961-2965
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• 2012

Mesoporous carbons with tailored pore size were prepared by using sucrose as the carbon source and silicas as the templates. The silica templates were obtained from a hydroxypropyl-${\beta}$-cyclodextrin-silica hybrids using ammonium perchlorate oxidation at different temperatures to remove the organic matter. The structures and surface chemistry properties of these carbon materials were characterized by $N_2$ adsorption, TEM, SEM and FTIR measurements. The catalytic performances of these carbon materials were investigated through the reduction of nitroaromatic using hydrazine hydrate as the reducing agent. Compared with other carbon materials, such as active carbon, and carbon materials from the silica templates obtained by using calcination to remove the organic matter, these carbon materials exhibited much higher catalytic activity, no obvious deactivation was observed after recycling the catalyst four times. Higher surface area and pore volume, and the presence of abundant surface oxygen-containing functional groups, which originate from the special preparation process of carbon material, are likely responsible for the high catalytic property of these mesoporous carbon materials.

• 대한화학회지
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• 제47권4호
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• pp.345-353
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• 2003

6-Chloro-3-methoxycarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(5) 또는 3-methoxycarbonylmethylene- 6-nitro-2-oxo-1,2,3,4-tetrahydroquinoxaline(6)을 hydrazine hydrate와 반응시켜 3-hydrazinocarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline류(7, 8)를 합성하였다. 화합물 7 또는 8을 치환 벤즈알데히드류 및 헤테로고리 알데히드류와 반응시켜 quinoxaline류(9-14)를 각각 합성하였다. 합성한 화합물들은 dimethyl sulfoxide 용액에서 enamine형, methylene imine형 또는 enamine형, methylene imine형, enaminol형 사이에 토토머화 현상을 나타내었는데, 이들의 토토머 비를 1H NMR로서 측정하였다.

• 한국재료학회지
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• 제17권1호
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• pp.50-55
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• 2007

Ultra-fine Copper powder for a conductive paste in electric-electronic field have been synthesized by chemical reduction of aqueous $CuSO_4$ with hydrazine hydrate $(N_2H_4{\cdot}H_2O)$ as a reductor. The effect of reaction conditions such as dispersant and reaction temperature on the particle size and shape for the prepared Cu powders was investigated by means of XRD, SEM, TEM and TGA. Experiments showed that type of dispersant and reaction temperature were affected on the particle size and morphology of the copper powder. When the carboxymethyl cellulose (CMC) was added as a dispersant the relative mono-dispersed and spherical Cu powder was obtained. Cu powders with particle size of approximately 140nm and narrow particle size distribution were obtained from 0.3M $CuSO_4$ with adding of 0.03M CMC and 40ml $N_2H_4{\cdot}H_2O$ at a reaction temperature of $70^{\circ}C$.

• 대한화학회지
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• 제47권3호
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• pp.241-249
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• 2003

3-(1-Ethoxycarbonyl)ethyl-1,2-dihydro-2-oxoquinoxaline(8)을 hydrazine hydrate와 반응시켜 3-(1-hydrazinocarbonyl)ethyl-2-hydroxyquinoxaline(9)을 합성하였고, 화합물 9를 치환 벤즈알데하이드류 또는 heteroaryl aldehyde류와 반응시켜 2-hydroxyquinoxaline류(10-12)를 합성하였다. 또한 화합물 9를 alkyl (ethoxymethylene)- cyanoacetate류 또는 ethoxymethylenemalononitrile과 반응시켜 분자내 고리화반응에 의하여 5-amino-1-[2-(3-hydroxyquinoxalin-2-yl)propanoyl]-pyrazole류(13)를 합성하였다. 얻어진 화합물 10-13은 dimethyl sulfoxide 용액에서 lactam형과 lactime형 사이에 토토머화 현상을 나타내었는데, 이들의 토토머 비를 $^1H$ NMR로서 측정하였다. 그리고 합성한 화합물들에 대한 제초력과 살균력도 조사하였다.

• 대한화학회지
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• 제45권5호
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• pp.454-460
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• 2001

3-Methoxycarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(7)을 hydrazine hydrate와 반응시켜 3-hydrazinocarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(8)을 합성하였다. 화합물 8을 alkyl (ethoxymethylene)cyanoacetate류와 반응시켜 [(quinoxalin-2-ylidene)ethanoyl]-1H-pyrazole류(9)를 합성하였고, 화합물 9b를 N-alkylaniline류와 반응시켜 N-alkyl-(quinoxalin-2-ylidene)-N-phenylethanamide류(10)를 합성하였다. 얻어진 화합물 9, 10은 용액에서 enamine 형과 methylene imine 형 사이에 토토머화 현상을 나타내었는데, 이들의 토토머비를 $^1H$ NMR 로서 측정하였다.

• 대한화학회지
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• 제44권5호
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• pp.435-440
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• 2000

2-Methoxycarbonylmethylene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one(5)을 hydrazine hydrate와 ethylenediamine을 반응시켜 2-hydrazinocarbonylmethylene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one(6)과 2-aminoethylcarbamoylmethylene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one(7)을 각각 합성하였다. 화합물 6 또는 7을 치환 벤즈알데히드류 및 헤테로아릴 알데히드류와 반응시켜 pyrido[2,3-b]pyrazin류(8-13)를 각각 합성하였다. 몇가지 pyrido[2,3-b]pyrazin은 용액에서 enamine형,methylene imine형, methylene imine형,enaminol형 사이에 토토머화 현상을 나타내었는데, 이들의 토토머 비는 1H NMR로서 측정하였다.