• Journal of the Korean Chemical Society
• /
• v.34 no.5
• /
• pp.490-497
• /
• 1990

Two synthetic routes for the 1,4-diboracyclohexene-2 ring 8 have been developed. Method i) starts with 1,2-bis(dichloroaluminyl)ethane, in which the AlCl$_2$ group is replaced by BCl$_2$. Exchange of the chlorine with BI$_3$ in 1,2-bis-(dichloroboryl)ethane yields the corresponding iodo compound, which reacts with the alkynes to heterocycles 8a, b in good yield. In method ii) B$_2$Cl$_4$ is added to alkenes, replacement of chlorine with BI$_3$ yields the bis(diiodoboryl)ethane derivatives which undergo redox reactions with alkynes to give 8c, d. The diiodo derivative 8a forms the pyridine adduct 9a, and reacts with ether to give the ethoxy derivative 8f. 8a-d react with AlMe$_3$ to yield the corresponding dimethyl derivatives 8g-j, which give unstable radical anions when treated with potassium in THF. The ESR parameters are reported. In electrochemical experiments irreversible reductions of 8g-j are observed. 8g-j react with (C$_5$H$_5$)Co(C$_2$H$_4$)$_2$ to give the intermediate 16 VE complexes (C$_5$H$_5$)Co(8), in which C-H activation occurs with formation of the corresponding red 1,4-diboracyclohexadiene complexes 10. The X-ray structure analyses of 10h and 10j are reported.

• The Journal of Korean Medicine
• /
• v.25 no.2
• /
• pp.67-76
• /
• 2004

Objectives : This study was designed to investigate the protective mechanisms of Palmul-tang on hypoxia-induced cytotoxicity in H9c2 cardiomyoblast cells. Methods : In this study, we used H9c2 cells. Cells were subjected to hypoxia in the absence and presence of $1000\mu\textrm{g}/ml$ Palmul-tang for 24 hrs. Cells were treated with various concentrations of Palmul-tang for 24 hrs. Cell viability was measured by MTT assay. Hypoxia markedly decreased the viability of H9c2 cells, which was characterized with apparent apoptotic features such as chromatin condensation as well as fragmentation of genomic DNA and nuclei. Results : Palmul-tang significantly reduced hypoxia-induced cell death and apoptotic characteristics. Also, Palmul-tang prevented mitochondrial dysfunction including the disruption of mitochondrial membrane permeability transition (MPT) and an increase in expression of apoptogenic Bcl-2 proteins in hypoxia-H9c2 cells. Conclusions; This study suggests that the protective effects of Palmul-tang against hypoxic damages may be mediated by the modulation of Bcl-2, Bax expression.

• Applied Chemistry for Engineering
• /
• v.17 no.6
• /
• pp.638-643
• /
• 2006

Pyrolytic reaction study of dichloromethane ($CH_{2}Cl_{2}$) in excess hydrogen was performed to investigate pyrolytic reaction pathways at a pressure of 1 atm with residence times of 0.3~2.0 sec in the temperature range of $525{\sim}900^{\circ}C$. A constant feed molar ratio $CH_{2}Cl_{2}$:$H_{2}$ of 4:96 was maintained through the experiment. Reagent loss and product formation were monitored by using an on-line gas chromatograph, where batch samples were analyzed by GC/MS. Complete destruction(99%) of the parent reagent was observed at temperature near $780^{\circ}C$ with residence time over 1 sec. Major products observed were $CH_{3}Cl$, $CH_{4}$, $C_{2}H_{4}$, $C_{2}H_{6}$, and HCl. Minor products included $CHClCCl_{2}$, CHClCHCl, $CH_{2}CHCl$, and $C_{2}H_{2}$. The pyrolytic reaction pathways to describe the important features of intermediate product distributions and reagent loss, based upon thermodynamic and kinetic principles, were suggested. The results of this work provided a better understanding of pyrolytic decomposition processes which occur during the pyrolysis of $CH_{2}Cl_{2}$ and similar chlorinated methanes.

• YAKHAK HOEJI
• /
• v.31 no.1
• /
• pp.40-41
• /
• 1987

4-Hydroxy-2H-1, 2-benzothiazine-3-carboxylic acid 1a was reacted with 2 equivalents of dicyclohexylcarbodiimide (DCC) to give 2-cyclohexyl-3-cyclohexylimino-4,5-dihydro-1H-imidazo [1,5-b][1,2] benzothiazine-10, 10a-dyhydro-1,10-dione 5,5-dioxide 2a and dicyclohexylurea (DCU). On the other hand 2-substituted-4-hydroxy-2H-1, 2-benzothiazine-3-carboxylic acid 1,1-dioxide 1b or c was reacted with DCC to give 2-cyclohexylimino-3-cyclohexyl-5-alkyl-4-oxo-2,5H-1,3-oxazino [5,6-c]-1,2-benzothiazine 6,6-dioxide 2b or c and DCU.

• Journal of the Korean Chemical Society
• /
• v.32 no.4
• /
• pp.390-405
• /
• 1988

The chlorination of $C_7H_16,\;C_8H_18,\;C_10H_22,\;and\;(Me_2CH)_2$ with N-Chlorosuccinimide, tert-BuOCl, $CCl_3SO_2Cl,\;CCl_4,\;CCl_3SCl,\; PCl_5,\;and\;Cl_2\;in\;C_6H_6\;or\;CS_2$ which both form loose complexes with $Cl_2$ atoms yielded mixtures of isomeric monochloroalkanes which were analyzed quantitatively. An isomer ratio differing from that known for the substitution of paraffinic hydrocarbons was observed. The isomer distribution observed is the result of the combined effects of the differing C-H dissociation energies of the different types of H atoms of the alkane and of the free energy of the attacking radical with polar effects of the attacking radical as well as of the hydrocarbon.

• Preventive Nutrition and Food Science
• /
• v.2 no.3
• /
• pp.241-245
• /
• 1997

Inhibitory effects of kimchi extracts on arcinogen-induced cytotoxicity and transformation in C3H/10T1/2 cells were studied. The methanol extract (500㎍/ml) of fresh (unfermented kimchi), and 3-week-fermented kimchi (properly ripened kimchi at 5℃) inhibited 3-methylcholanthrene (MCA)-induced cytotoxicity in C3H/10T1/2 cells by 84 and 99%, respectively. The inhibitory effect of 3-week-fermented kimchi was higher than that of the fresh kimchi at same test condition. The methanol soluble fraction, and haxane extract of 3-week fermented kimchi also surpressed the cytotoxicity of FC3H/10T1/2 cells mediated by 7,12-dimethylbenz[a]anthracene(DMBA) and N-methyl-N'-nitro-N-nitrosoguanidine(MNNG). Furthermore, MCA-induced transformation of C3H/10T/1/2 cells was significantly inhibited by the methanol soluble fraction of 3-week fermented kimchi. With these results, we suggest that kimchi might have anticarcinogenic effect in part due to inhibition of carcinogen-induced cytotoxicity and transformation of C3H/10T/1/2 cells.

• The Journal of Korean Medicine
• /
• v.25 no.3
• /
• pp.149-159
• /
• 2004

Backgrounds & Objectives : The water extract of Gyungokgo (GOG) has traditionally been used for treatment of general weakness and hemoptysis in oriental medicine. However, little is known about the mechanism by which the water extract of GOG rescues cells from these damages. This study was designed to investigate the protective mechanisms of GOG on H2O2­induced cell death in H9c2 cardiomyoblasts. Methods : In this study, we used H9c2 cells. Cells were treated with oxidative stress in the absence and presence of 1000㎍/ml GOG for 12hrs. Cells were treated with various concentrations of GOG for 12hrs. Cell viability was measured by MTT assay. Oxidative stress, which markedly decreased the viability of H9c2 cells, was characterized by apparent apoptotic features such as chromatin condensation as well as fragmentation of genomic DNA and nuclei. Results : GOG significantly reduced H₂O₂-induced cell death and apoptotic characteristics. The cotreatment of GOG and H₂O₂ in H9c2 cells also induced the phosphorylation of ERKs in a time-dependent manner. Moreover, PD098059, a MEK1 (upstream activator of ERK) inhibitor attenuated the protective effect of GOG on H₂O₂-induced cytotoxicity in H9c2 cardiomyoblast cells. Conclusions : These results suggest that MEK/ERK pathways play important roles in the protective effects of GOG in H9c2 cells. Taken together, they suggest that the protective effects of the water extracts of GOG against oxidative damages may be mediated by the regulation of HO-1, Fas/FasL and Bcl-XS proteins.

• Food Science and Preservation
• /
• v.6 no.2
• /
• pp.153-160
• /
• 1999

This study was carried out to investigate the production of C$_2$H$_4$ and CO$_2$, and the change of flesh firmness and peel color in 'Fuji' apples during CA storage. ACC oxidase activity was more inhibited by the low O$_2$ concentration, and the low level of internal C$_2$H$_4$ in apples was maintained under the low O$_2$ conditions during 8 months storage. Especially, the level of internal C$_2$H$_4$ in apples was maintained below 1 ppm during storage under 1% O$_2$+1% CO$_2$ at 0$^{\circ}C$, and not much changed for 7 days in air at 20$^{\circ}C$ after storage. The influence of CO$_2$ on the C$_2$H$_4$ production was dependent on the O$_2$ concentration. Increasing of CO$_2$ concentration with 3% O$_2$ decreased the C$_2$H$_4$ Production during storage, but that with 1% O$_2$increased. Internal C$_2$H$_4$ concentration and the rate of CO$_2$ evolution in apples showed the close correlation. Internal CO$_2$ concentration of apples was positively related to the rate of CO$_2$ evolution and maintained the lower level in 1% O$_2$+1% CO$_2$ than the other conditions during storage but nu different in the increment after storage. The relationship between C$_2$H$_4$ and CO$_2$ production was exhibited in CA and the short-term air stored apples, but not in the long-term air stored apples. Loss of flesh firmness and green color in apples was more less in storage condition retarded effectively the production of C$_2$H$_4$ and CO$_2$.

• Bulletin of the Korean Chemical Society
• /
• v.15 no.2
• /
• pp.100-101
• /
• 1994

• Environmental Analysis Health and Toxicology
• /
• v.31
• /
• pp.2.1-2.4
• /
• 2016

Objectives In this study, we investigated the biodegradation features of 4 perfluorooctanesulfonate (PFOS) alternatives developed at Changwon National University compared to those of PFOS. Methods Biodegradation testing was performed with microorganisms cultured in the good laboratory practice laboratory of the Korea Environment Corporation for 28 days following the Organization for Economic Cooperation and Development guidelines for the testing of chemicals (Test No. 301 C). Results While $C_8F_{17}SO_3Na$, PFOS sodium salt was not degraded after 28 days, the 4 alternatives were biodegraded at the rates of 20.9% for $C_{15}F_9H_{21}S_2O_8Na_2$, 8.4% for $C_{17}F_9H_{25}S_2O_8Na_2$, 22.6% for $C_{23}F_{18}H_{28}S_2O_8Na_2$, and 23.6% for $C_{25}F_{17}H_{32}O_{13}S_3Na_3$. Conclusions $C_{25}F_{17}H_{32}S_3O_{13}Na_3$, $C_{23}F_{18}H_{28}S_2O_8Na_2$, and $C_{15}F_9H_{21}S_2O_8Na_2$ were superior to PFOS in terms of biodegradation rates and surface tension, and thus they were considered highly applicable as PFOS alternatives. Environmental toxicity, human toxicity, and economic feasibility of these compounds should be investigated prior to their commercialization.