• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.536-541
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• 1991

To enhance the productivity of fruit flavor compounds from whey by the lactose fermenting yeast, Kluyveromyces lactzs ATCC 8585 was treated with N-methyI-N'-nitro-N-nitrosoguanidine (NTG). After the NTG treatments, a mutant showing resistance to antifungal activity of geraniol, and strong fruity but low yeasty flavor was selected and named as K. lactis 450 K. Flavor compounds from 3-day culture broth were extracted with pentane-dichloromethane (2:l) and the concentrated oleoresins were analyzed by gas chromatography. The mutant strain produced more classes and larger amount of flavor compounds than the parent stlain. Tentatively identified volatile compounds from the culture of the mutant were: terpenes such as myrcenol; alcohols such as cis-3-hexenol, n-hexanol; esters such as ethyl isovalerate, cis- 3-hexenyl n-butyrate, n-amyl-n-hexanoate, phenyl ethyl n-propioate; ketones such as methyl vinyl ketones; other compounds such as vanillin, 3-methylcoumarin.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1337-1342
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• 2014

A novel and convenient route for the synthesis of a series of thalidomide derivatives is described. Compound 2 was cyclized with different amines under alkaline condition to obtain 4-nitro substituted phthalimidines 3a-d. Hydroxylactams 4a-d were produced via bromination and hydroxylation. Different acyl chlorides were reacted with hydroxylactams to provide the desired esters 5a-d. All compounds were evaluated by MTT assay for their inhibitory activities against HCT-116, MG-63, MCF-7, HUVEC and HMVEC cell lines in vitro. Most of them showed no obvious cytotoxic effect on normal human cells, compounds 4a-d, $5a_2$, $5a_4$, $5a_5$, $5b_2$, $5c_2$ and $5d_2$ exhibited potent antitumor activities, among which compounds $5a_2$ and $5b_2$ were more effective than 5-FU.

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.612-617
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• 1991

The approximate rates and stoichiometry of the reaction of excess 1,3,2-biphenyldioxaborepin [2,2'-biphenoxyborane (BPB)] with selected organic compounds containing representative functional groups under the standardized conditions (tetrahydrofuran, hydride to compound being 4 : 1, room temperature) was examined in order to define the characteristics of the reagent for selective reductions and compare its reducing power with those of other substituted boranes. The results indicate that BPB is unique and the reducing power is much stronger than that of other dialkoxyboranes, such as catecholborane and di-s-butoxyborane. BPB reduces aldehydes, ketones, quinones, lactones, tertiary amides, and sulfoxides readily. Carboxylic acids, anhydrides, esters, and nitriles are also reduced slowly. However, the reactions of acid chlorides, epoxides, primary amides, nitro compounds, and disulfides with this reagent proceed only sluggishly.

• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.313-318
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• 1987

The approximate rate and stoichiometry of the reaction of excess Thexylbromoborane-methyl sulfide, $ThxBHBr{\cdot}SMe_2,$ with selected organic compounds containing representative functional groups under standardized conditions (methylene chloride, $0^{\circ}C)$ were studied in order to characterize the reducing characteristics of the reagent for selective reductions. The selectivity of the reagent was also compared to the selectivity of thexylchloroborane-methyl sulfide. Thexylbromoborane appears to be a much milder and hence more selective reducing agent than thexylchloroborane. The reagent tolerates many organic functionalities. Thus, the reagent shows very little reactivity or no reactivity toward acid chlorides, esters, epoxides, amides, nitro compounds including simple olefins. However, this reagent can reduce aldehydes, ketones, carboxylic acids, nitriles, and sulfoxides. Especially the reagent reduces carboxylic acids including ${\alpha},{\beta}$ -unsaturated ones and nitriles to the corresponding aldehydes. In addition to that, thexylbromoborane shows good stereoselectivity toward cyclic ketones, much better than the chloro-derivative.

• Applied Biological Chemistry
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• v.17 no.3
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• pp.149-176
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• 1974

Eight substituted diphenyl ether herbicides and some of their photoproducts were studied in terms of solution phase photolysis under simulated environmental conditions by using a Rayonet photochemical reactor. The test compounds absorbed sufficient light energy at the wavelength of 300 nm to undergo various photoreactions. All the photoproducts were confirmed by means of tlc, glc, ir, ms, and/or nmr spectrometry. The results obtained are summarized as follows: Solution phase photolysis of C-6989: An exceedingly large amount of p-nitrophenol formed strongly indicates the readiness of the ether linkage cleavage of this compound as the main reaction in all solvents used. Photoreduction of nitro to amino group(s) and photooxidation of trifluoromethyl to carboxyl group were recognized as minor reactions. Aqueous photolysis of p-nitrophenol: Quinone(0.28%), hydroquinone (0.66%), and p-aminophenol (0.42%) were confirmed as photoproducts, in addition to a relatively small amount of an unknown compound. The mechanisms of formation of these products were proposed to be the nitro-nitrite rearrangement via $n{\rightarrow}{\pi}^*$ excitation and the photoreduction through hydrogen abstractions by radicals, respectively. Solution phase photolysis of Nitrofen: Photochemical reduction leading to the p-amino derivative was the main reaction in n-hexane. In aqueous solution, the photoreduction of nitro to amino group and hydroxylation predominated over the ether linkage cleavage. Nucleophilic displacement of the nitro group by hydroxide ion and replacement of chlorine substituents by hydroxyl group or, to a lesser extent, hydrogen were also observed as minor reactoins. Solution phase photolysis of MO-338: Photoreduction of the nitro to amino group was marked in the n-hexane solution photolysis. In the aqueous solution, photoreduction of the nitro substituent and hydroxylation were the main reactions with replacement of chlorine substituents by the hydroxyl group and hydrogen, and cleavage of the ether linkage as minor reactions. Photolyses of MC-4379, MC-3761, MC-5127, MC-6063, and MC-7181 in n-hexane and cyclohexane: Photoreduction of the nitro group leading to the corresponding amino derivative and replacement of one of the halogen substituents by hydrogen from the solvent used were the key reactions in each compound. Aqueous photolysis of MC-4379: Cleavage of the ether linkage, replacement of the carboxymethyl by hydroxyl group, hydroxylation, and replacement of the nitro by hydroxy group were prominent with photoreduction and dechlorination as minor reactions. Aqueous photolysis of MC-3761: Cleavage of the ether linkage, replacement of the carboxymethyl by hydroxyl group, and photoreduction followed by hydroxylation were the main reactions. Aqueous photolysis of MC-5127: Replacement of carboxyethyl by hydrogen was predominant with ether linkage cleavage, photoreduction, and dechlorination as minor reactions. It was obvious that the decarboxyethylation proceeded more readily than decarboxymethylation occurring in the other compounds. Aqueous photolysis of MC-6063: Cleavage of the ether linkage and photodechlorination were the main reactions. Aqueous photolysis of MC-7181: Replacement of the carboxymethyl group by hydrogen and monodechlorination were the remarkable reactions. Cleavage of the ether linkage and hydroxylation were thought to be the minor reactions. Aqueous photolysis of 3-carboxymethyl-4-nitrophenol: The photo-induced Fries rearrangement common to aromatic esters did not appear to occur in the carboxymethyl group of this type of compound. Conversion of nitro to nitroso group was the main reaction.

• YAKHAK HOEJI
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• v.35 no.1
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• pp.7-10
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• 1991

For the purpose of developing of anticariogenic agents, P-phenylphenol derivatives were synthesized and determined their antibacterial activities against a cariogenic bacterium, Streptococcus mutans. Among synthetic compounds, 2-nitro-6-bromo-p-phenylphenol showed as potent antibacterial activity as magnolol and honokiol.

• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.436-438
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• 1989

• KSBB Journal
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• v.11 no.6
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• pp.623-629
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• 1996

m-Bromonitrobenzene was reduced to m-bromoaniline with a 86∼91% yield by either baker's yeast (Sigma type I) or glucose and baker's yeast in conjunction with glucose. Nitrosobenzene was reduced to aniline in good yields using baker's yeast(Sigma type I) only.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1319-1325
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• 2010

Tyrosinase ubiquitously existing from microorganisms to animals and plants is known to be the most critical and rate limiting enzyme during melanin biosynthesis. In order to develop new tyrosinase inhibitor we have synthesized 14 diphenyl ether compounds possessing hydroxyl, bromo, and nitro groups in the structure. Among the compounds prepared, 18 and 19 have shown much stronger inhibition of tyrosinase monophenolase function than arbutin used as a positive control. Both compounds 18 and 19 possess para-hydroxyphenyl moiety in their structure, which might reinforce the importance of p-hydroxyphenyl group in the tyrosinase inhibitory process. In the DPPH radical scavenging activity test, none of the compounds even 18 and 19 showed significant antioxidant activity. The results suggest that elaborate adjustment of diphenyl ether analogues with proper substituents have potential to be developed as new skin whitening agents working on the tyrosinase function.

• Journal of Society of Preventive Korean Medicine
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• v.13 no.2
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• pp.39-50
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• 2009

Objectives : In order to evaluate the cytotoxicity of 3,4,5-trihydroxybenzoic acid and related compounds on the growth of normal cell lines and human oral epithelioid cell line, cell viability, cell adhesion ability, and morphological changes of cells were examined. Methods : We measured the cytotoxicity of 3,4,5-trihydroxybenzoic acid and related compounds with 3-[4,5-dimethyl-thiazol-2-yl]-2,5-diphenyltetrazolium bromide-[MTT), and 2,3-bis-[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium -5-caboxanilide-[XTT) methods. Results : The cytotoxicity of 3,4,5-trihydroxybenzoic acid($IC_{50}$, $2,552.40\;{\mu}M$) was low according to the toxic criteria. Cytotoxic effect of 3,4,5-trihydroxybenzoic acid and related compounds against $IC_{50}$ value in cell morphology increased in a concentration-dependent manner. In light microscopy, $100\;{\mu}M$ 3,4,5-trihydroxy-benzoic acid showed th highest cytotoxic activity. Conclusions : These results suggest that 3,4,5-trihydroxybenzoic acid may have a potential anticancer activity.