• 생약학회지
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• 제8권1호
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• pp.23-29
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• 1977

The $^{13}C-chemical\;shifts$ of the phenolic coumarine derivatives, aesculetin, daphnetin and herniarin were studied on the basis of my previous report. All spectral data found in this report could be utilized to the structure elucidation of the unknown phenolic coumarine derivatives and other phenolic compounds. In addition, it is suggested that a long range coupling may occur in the following structure as represented by arrow.

• Journal of Photoscience
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• 제8권2호
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• pp.70-73
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• 2001

The chlorin-bromine building block was constructed and applied to synthesize $\delta$-bromo compounds of methyl pyropheophorbide-a. The visible spectra of the title compounds were discussed.

• 대한화학회지
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• 제54권4호
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• pp.429-436
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• 2010

Guanine (1)으로부터 생물활성이 있는 halogenopurines계 화합물을 합성하였다. Guanine을 acetic anhydride와 반응시켜서 2,9-diacetylguanine (2-1)을 합성하여 얻어진 화합물을 $POCl_3$와 반응시켜서 화합물 3a를 합성하고, 다음 단계에서 2-amino-6-halogenopurines (3b-d)를 합성하였다. 2-Halogenopurines (2-2a-d, 4-2a-d, 5a-d)을 2-amino-6-substituted purines (1, 3a, 4-1)로부터 효율적으로 합성한 후에, 새로운 화합물인 2-2a, 2-2c, 2-2d, 4-2c, 4-2d, 5b, 5c 및 5d를 합성하였다. 합성한 화합물의 구조를 원소분석, $^1H$ NMR, mass spectral data로 확인하였으며, 합성한 화합물에 대한 항균 활성을 시험하였다.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4316-4320
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• 2011

The effects of various hydroxide compounds on base stacking (BS) were investigated for pre-concentration of DNA molecules in capillary electrophoresis (CE). In BS, hydroxide ions ($OH^-$) were electrokinetically introduced after DNA sample injection. A neutralization reaction occurred between the $OH^-$ and $Tris^+$ of the running buffer, which resulted in a zone of lower conductivity. Within the low conductivity zone of the high electric field, the DNA molecules moved more rapidly and were concentrated in front of the low conductivity zone. At the same BS conditions of CE, the enhanced sensitivity of the DNA samples was dependent on the kind of multivalent cations in the hydroxide compounds. Except for LiOH, the hydroxide compounds with monovalent cations showed more effective BS than those with divalent cations because of solubility, ionic strength and electronegativity. The order of hydroxide compounds that enhance the detection sensitivity of DNA molecules was as follows: NaOH > $NH_4OH$ > KOH > $Ba(OH)_2$ > $Sr(OH)_2$ > LiOH > $Ca(OH)_2$ > $Mg(OH)_2$. $NH_4OH$, KOH and $Ba(OH)_2$ proved to be efficient hydroxide compounds to use as effective BS reagents in CE instead of NaOH.

• Food Science and Biotechnology
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• 제18권6호
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• pp.1447-1458
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• 2009

Volatile extracts obtained from traditional Chinese-type soy sauces prepared with soybean (SSSB) and defatted soy meal (SSDSM) by solid phase microextraction (SPME) and direct solvent extraction (DSE) were analyzed by gas chromatography-mass spectrometry (GC-MS). The volatile flavor compounds and relative contents of different chemical classes detected in SSSB and SSDSM were compared for their differences. Results showed that significant differences in both constituents of volatile flavor compounds and relative contents of different chemical classes were observed for both kinds of soy sauces. A total of 152 and 131 compounds were identified in SSSB and SSDSM, respectively, and 102 volatile flavor compounds were common in both kinds of soy sauces. Moreover, relative contents of acids, aldehydes, esters, furan(one)s, miscellaneous compounds, phenols, pyrazines, pyrrol(idinon)es, and sulfur-containing compounds in both kinds of soy sauces were all significantly different.

• Advances in environmental research
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• 제2권2호
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• pp.143-153
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• 2013

This study investigated the concentrations of odourous compounds in air, leachate, stream and well in and around Taju-Bello dumpsite. Meteorological parameters (temperature, relative humidity, wind velocity) and six odour families comprising sulphur ($H_2S$), ammonia ($NH_3$), aromatic (benzene, toluene, ethylbenzene, styrene, p-xylene, m-xylene), aliphatic (hexane), oxygenated (formaldehyde, acetaldehyde) and halogenated (tetrachloroethene, trichloroethene, carbontetrachloride) compounds were measured. Meteorological parameters suggested low dispersal of pollutants at L1 with possible perspiration and suffocation from exposure to high temperature, relative humidity and low wind velocity. The trend of abundance of odourous compounds at studied locations is of the order dumpsite (L1) > leachate (L4) > 100 m away from dumpsite (L2) > 200 m away from dumpsite (L3) > stream (L5) > well (L6). $H_2S$, Oxygenated and aromatic compounds were the major contributors to odour strength in these locations. Correlation, factor and cluster analyses of the data revealed similarities of sources as biogenics and xenobiotics inherent in the wastes as the main sources of these odourous compounds.

• Bulletin of the Korean Chemical Society
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• 제21권1호
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• pp.110-117
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• 2000

A series of new liquid crystalline dimesogenic compounds with chiral tails was synthesized, and their thermal and liquid crystalline properties were studied. The chain length of the central polymethylene spacers (x) was varied from dimethylene (2) to decamethylene (12). These compounds were characterized by elemental analysis, IR and NMR spectroscopy, differential scanning calorimetry (DSC), and cross-polarizing microscopy. All compounds were found to be enantiotropically liquid crystalline, and the values of melting ($T_m$) and isotropization temperature ($T_i$) as well as enthalpy change (Δ$H_i$) and entropy change for isotropization (Δ$S_i$) decreased in a zig-zag fashion revealing the so-called odd-even effect as x increases. Their mesomorphic properties fall into three categories depending upon x; (a) compounds with x=2 and 4 formed two different mesophases, smectic and cholesteric phases in that order on heating, and vice versa on cooling, (b) compounds with x=3, 7, 8, 10 and 11 reversibly formed only the cholesteric phase, and (c) compounds with x=5, 6, 9 and 12 exhibited only a cholesteric phase on heating, whereas on cooling they formed two different mesophases, cholesteric and smectic phases, sequentially.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3381-3384
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• 2014

• Bulletin of the Korean Chemical Society
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• 제11권6호
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• pp.479-481
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• 1990

• 한국산업보건학회지
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• 제31권1호
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• pp.1-12
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• 2021

Objective: The purpose of this study was to contribute to the prevention of occupational diseases through the development of an automatic analysis program for evaluating workers' exposure to hazardous chemical substances. Methods: The authors selected chemical substances that caused occupational disease in Korea and chemical substances that are frequently used in industrial sites as target substances for a GC-MS automatic analysis program. The target substances are organic compounds which can be measured by a passive sampler. The automatic analysis program was studied using various raw data obtained from GC-MS analysis for the target substances. Results: A total of 48 organic compounds that can be measured with a passive sampler were selected as target substances for the GC-MS automatic analysis program. The selected compounds included substances that caused occupational disease, substances related to C1 and D1 in special health examinations, and substances for which work environment measurements have been frequently conducted. The GC-MS automatic analysis program was developed by combining information mainly on retention time and mass spectrum. The GC-MS automatic analysis program is designed to analyze unknown samples by comparing the mass spectrum and retention time of the samples to those of reference materials. To evaluate the stability of the program, samples at about the 30-50% level of OELs were prepared and analyzed with the GC-MS automatic analysis program, resulting in stable results for all 48 organic compounds. Conclusion: An automatic analysis program for a total of 48 organic compounds was developed using a GC-MS system that can analyze organic compounds. Unknown samples that contain the 48 organic compounds can be automatically analyzed by the developed program. It is anticipated that it can contribute to the prevention of occupational diseases through an GC-MS automatic analysis program that can quickly provide workers with information on exposure to chemical substances.