• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.47-51
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• 2008

A simple synthetic strategy is described for one-pot synthesis of 5,7-diaryl-4,4-dimethyl-4,5,6,7-tetrahydropyridino[3,4-d]-1,2,3-selenadiazoles (11-15) in the presence of NaHSO4.SiO2 as a heterogeneous catalyst in dry media under microwave irradiation.Key words: One-pot synthesis, 3,3-Dimethyl-2,6-diarylpiperidin-4-one; 1,2,3-Selenadiazoles; Selenium dioxide; NaHSO4.SiO2 Heterogeneous catalyst.

• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1569-1574
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• 2005

To develop new hole-blocking materials for phosphorescent organic light-emitting diodes (PhOLEDs), 5,6-dihydro-2,9-diisopropyl-4,7-diphenyl[1,10]phenanthroline (1) and 5,6-dihydro-2,9-diisopropyl-4-(4-methoxyphenyl)-7-phenyl[1,10]phenanthroline (2) were synthesized. While the absorption spectrum of 1 is very similar to that of 2, the photoluminescence spectrum of 1 has the feature of the narrower and blue-shifted blueviolet emission at the peak of 356 nm compared to that of 2. The HOMO and LUMO energy levels of 1 and 2 were estimated from the measurement of cyclic voltammetry, and 1 has the appropriate levels for a holeblocking layer (HBL). The use of 1 as a HBL in a green PhOLED led to good efficiency of 23.6 cd/A at 4.4 mA/$cm^2$.

• Nano
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• v.13 no.11
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• pp.1850132.1-1850132.14
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• 2018

The direct synthesis of metal-organic frameworks (MOFs) with acidic and basic active sites is challenging due to the introduction of functional groups by post-functionalization method often jeopardize the framework integrity. Herein, we report the direct synthesis of acid-base bifunctional MOFs with tuning acid-base strength. Employing modulated hydrothermal (MHT) approach, microporous MOFs named $UiO-66-NH_2$ was prepared. Through the ring-opening reaction of 1,3-propanesultone with amino group, $UiO-66-NH_2-SO_3H-type$ catalysts can be obtained. The synthesized catalysts were well characterized and their catalytic performances were evaluated in one-pot glucose to 5-HMF conversion. Results revealed the acid-base bi-functional catalyst possessed high activity and excellent stability. This work provides a general and economically viable approach for the large-scale synthesis of acid-base bi-functional MOFs for their potential use in catalysis field.

• Fibers and Polymers
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• v.3 no.2
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• pp.55-59
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• 2002

The thermal reaction of acetoacetanilide in the presence of aniline or phenol yielded carbanilide in quantitative yields. This reaction was applied to the synthesis of polyurea. Bisacetoacetamides were prepared from diamines and diketene in DMF. They were thermally polymerized in the presence of phenol or a diamine (6FDA) to yield polyureas of low molecular weights. The polymers were soluble in DMSO and NMP. $^1{H-NMR}$ analysis showed that they had amino group terminated structures. Poly(urea-imide) was synthesized by the reaction of an oligourea diamine with pyromellitic dianhydride in NMP. The concentration of terminal amino groups was determined by an acid-base titration. The thermal property of poly(urea-imide) was evaluated by thermogravimetric analysis (TGA). Initial decompisition took place at 332-$350^{\circ}C$.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.1
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• pp.1-12
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• 2019

Objective: Significant concerns have been raised over chemical exposure and potential health risks such as increased cancer mortality among laboratory workers. The aim of this study was to investigate the overall exposure and unit task exposure levels of researchers in organic synthesis laboratories at universities. Methods: Seventy-seven personal Time-weighted average(TWA) samples and 139 task-based samples from four organic synthesis laboratories at two universities were collected over three days. The concentrations of acetone, chloroform, dichloromethane(DCM), diethyl ether, ethyl acetate, n-hexane, tetrahydrofuran(THF), benzene, toluene, and xylene were determined using the GC-FID. Results: The most frequently used chemicals in the laboratories were acetone, DCM, n-hexane, methanol, and THF. Carcinogens such as benzene, chloroform, and DCM were used in one or more laboratories. The TWA full-shift exposures of researchers to acetone was the highest(ND-59.3 ppm). Benzene was observed above the occupational exposure limit in 18-40% of the samples. The levels of exposure to organic solvents were statistically different by task(p<0.05), while washing task was the highest. Washing was not perceived as a part of the real lab tasks. Rather it was considered as simple dish-washing or experimental preparation and performed in an open sink where exposure to organic solvents was unavoidable. TWAs and task-based concentrations were compared by substance, which suggests that TWA-based assessment could not reflect short-term and high concentration exposures. Conclusions: Laboratory workers may be exposed to various organic solvents at levels of concern. TWA-based measurement alone cannot guarantee holistic exposure assessment among lab workers as their exposures are very dependent on their tasks. Further investigation and characterization for specific tasks and overall chronic exposures will help protect lab workers from unnecessary exposure to chemicals while they perform research.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.339.2-339.2
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• 2002

Interest in the synthesis and chemistry of multidentate macrocyclic ligands is currently very high. Synthetic macrocycles arise from the fact that many biologically important molecules are metal complexes of macrocyclic organic systems: and in order to understand the mechanism of action of the naturally occurring complexes. chemists have resorted to the synthesis and study of so-called model systems. (omitted)

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1371-1376
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• 2006

BACE 1 ($\beta$-secretase), a membrane bound aspartic protease, is a key enzyme in the process of amyloid precursor protein (APP) into A$\beta$ peptide which is considered to play a causative role in Alzheimers Disease (AD). Here, we reported the synthesis and inhibitory activity of optically active 3-amino-4-aryl-piperidines.

• Archives of Pharmacal Research
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• v.28 no.6
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• pp.637-647
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• 2005

This work includes the synthesis of 15 final compounds (6a-h and 7b-h) as prod rugs of 5-ASA in the form of the acid itself, esters and amides linked by an amide linkage through a spacer to the endocyclic ring N of nicotinamide. Also, 15 new intermediate compounds were prepared. The target compounds (6b, 6f, 7b, and 7e-h) revealed potent analgesic and anti-inflammatory activities in comparison to sulfasalazine and 5-ASA. In addition, ulcerogenicity, $LD_{50}$, in vivo and in vitro metabolism of compound 7f were determined.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.490-493
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• 2003

Enzymatic synthesis of sugar fatty acid esters was investigated in organic solvent using Candida rugosa lipase. To overcome sugars insolubility in organic solvent, sugar absorption procedure was done on a silica gel. The product yield was determined by using ion Chromatography, with various factors such as reaction time, enzyme fatty acid molar ratio, number of carbon in fatty acid.

• Archives of Pharmacal Research
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• v.13 no.4
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• pp.306-309
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• 1990

The synthesis of 5-hyterocyclimethyl-2'-deoxyuridines (4a-f) has been accomplished by displacement reaction of 5-(bromomethyl)-3', 5'-di-O-acetyl-2'-deoxyuridine with heterocyclic compounds, followed by removal of acetyl protecting group with methanolic ammonia. The compoudns synthesized were evaluated the inhibitory effects on L1210 cell probiferation and antiviral activities against Herpes simplex virus type 1 (HSV-1) None of the compounds exhibited sufficient biological activities.