• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1467-1468
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• 2010

• Journal of the Korean Chemical Society
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• v.32 no.1
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• pp.71-78
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• 1988

The crown ether ring of 20, 21, 24, 25-tetranitrodibenzo-18-crown-6(TNDB-18-C-6) was cleaved by various alcoholic bases to give 2,4,5-trialkoxynitrobenzene derivatives and 4,5-dialkoxy-1,2-dinitrobenzene derivatives as the major products, and bis[(alkoxynitrophenoxy)ethyl]ether derivatives from partially cleaved crown ether ring as the minor products. The ring cleavage reaction of TNDB-18-C-6 with ethylene glycolic base resulted ring contraction through intramolecular nucleophilic cyclization of the initially formed ring cleavage product to give nitro derivatives of DB-14-C-4.

• 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.

• Bulletin of the Korean Chemical Society
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• v.15 no.5
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• pp.337-338
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• 1994

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.23-24
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• 2014

• Journal of Korea Foresty Energy
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• v.17 no.1
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• pp.56-70
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• 1998

This study was carried out to investigate the structural characteristics of kraft lignin and the wood degrading characteristics, the productivity of ligninolytic enzymes and the enzymatic degradation of kraft lignin by white-rot fungi. To purify kraft lignin, precipitation of kraft pulping black liquors of pitch pine meal was done by titration with lN $H_{2}SO_{4}$ reaching to pH 2, and isolation of the precipitates done by centrifugation. The isolated precipitates from pitch pine were redissloved in lN NaOH, reprecipitated by titration with lN $H_{2}SO_{4}$, washed with deionized water, and kept ofr analysis after freeze drying. Fractionation of the precipitates in solution by successive extraction with $CH_{2}Cl_{2}$ and MeOH, and the fractionates were named SwKL, SwKL I, SwKL II, and SwKL III for pitch pine kraft lignin. The more molecular weights of kraft lignin increased, the less phenolic hydroxyl groups and the more aliphatic hydroxyl groups. Because as the molecular weights increased, the ratio of etherified guaiayl/syringyl(G/S ratio) and the percentage were increased. The spectra obtained by 13C NMR and FTIR assigned by comparing the chemical shifts of various signals with shifts of signals from autherized ones reported. The optimal growth temperature and pH of white-rot fungi in medium were $28^{\circ}C$ and 4.5-5.0, respectively. Especially, in temperature and pH range, and mycelial growth, the best white-rot fungus selected was Phanerochaete chrysosporium for biodegradation. For the degradation pathways, the ligninolytic fungus jcultivated with stationary culture using medium of 1% kraft lignin as a substrate for 3 weeks at $28^{\circ}C$. The weight loss of pitch pine kraft lignin was 15.8%. The degraded products extracted successively methoanol, 90% dioxane and diethyl ether. The ether solubles were analyzed by HPLC. Kraft lignin degradation was initiated in $\beta$-O-4 bonds of lignin by the laccase from Phanerochaete chrysosporium and the degraded compounds were produced from the cleavage of $C\alpha$-$C\beta$ linkages at the side chains by oxidation process. After $C\alpha$-$C\beta$ cleavage, $C\alpha$-Carbon was oxidized and changed into aldehyde and acidic compounds such as syringic acid, syringic aldehyde and vanilline. And the other compound as quinonemethide, coumarin, was analyzed. The structural characteristics of kraft lignin were composed of guaiacyl group substituted functional OHs, methoxyl, and carbonyl at C-3, -4, and -5 and these groups were combinated with $\alpha$ aryl ether, $\beta$ aryl ether and biphenyl. Kraft lignin degradation pathways by Phanerochaete chrysosporium were initially accomplished cleavage of $C\alpha$-$C\beta$ linkages and $C\alpha$ oxidation at the propyl side chains and finally cleavage of aromatic ring and oxidation of OHs.

• Journal of Pharmaceutical Investigation
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• v.24 no.4
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• pp.273-279
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• 1994

The stability of three oximes, Hl-6 [(4-carbamoyl-2'[(hydroxyimino)-methyl]- 1,1'-oxydimethylenedi-(pyridinium chloride)], Hl-CN [(4 cyano-2'-[(hydroxyimino)-methyl] -1,1'-oxydimethylene-di-(pyridinium chloride)], and 2-PAM [pralidoxime chloride] in aqueous solutions was evaluated by HPLC assay. The rate of degradation is dependent on the pH as well as the temperature at which the solution is stored. The optimum pH for the stability of these oximes was pH 2 to 3. The degradation rate constant for 2-PAM ($k\;at\;70^{\circ}C$, $2.07{\times}10^{-4}/hr;\;E_a\;value$, 27.2 kcal/mol) was smaller than those for bis-pyridiniumoximes, Hl-6 ($k\;at\;70^{\circ}C$, $3.38{\times}10^{-3}/hr$) and Hl-CN ($k\;at\;70^{\circ}C$, $8.66{\times}10^{-3}/hr;\;Ea\;value$, 20.7 kcal/mol). In mechanistic analyses, it was found that Hl-CN was decomposed through not only the hydrolysis of nitrile group but also the cleavage of methylene ether bridge, in contrast to Hl-6 which was degraded mainly through the cleavage of methylene ether bridge.

• Journal of Forest and Environmental Science
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• v.13 no.1
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• pp.143-152
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• 1997

The decayed wood by Fomes pini (Thore) Lloyd required a smaller H factor than the sound wood for pulping to permanganate number 20. The H factors for the decayed wood pulping by the kraft and soda processes were reduced by 15% and 17%, respectively, in the presence of 1% anthraquinone. The wood components degraded by fungi are normally more readily solubilized in alkali than the corresponding components in sound wood. The nonphenolic ${\beta}$-O-4 type lignin model compound, veratrylglycerol-${\beta}$-guaiacyl ether(I), and phenolic model compound, syringylglycerol-${\beta}$-syringyl ether(III), were degraded by the white-rot fungi to yield ${\alpha}$-guaiacoxy-${\beta}$-hydroxypropioveratrone(II) from the former and ${\alpha}$-syringyloxy-${\beta}$-hydroxypropiosyringone(IV) from the latter. Structures of the degradation products indicated that C ${\alpha}$-oxidation could occur with white-rot fungi. It has been shown that the alkaline cleavage of ${\beta}$-aryl ether bonds in the lignin units is accelerated by the presence of ${\alpha}$-carbonyl groups.

• Korean Journal of Microbiology
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• v.20 no.2
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• pp.53-66
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• 1982

1. When Chong Ju and Chung Ju soils possessing different physicochemical properties were treated with 500 ppm of TOK and incubated in flooded anaerobic condition for 2, 4, and 6 months, respectively, they produced 4-Chloro-4'-amino diphenyl ether, 2,4-Dichloro-4'-amino diphenyl ether(amin-TOK), N-[4'-(4-Chlorophenoxy)] phenyl acetamide, and N-[4'-(4-Chlorophenoxy)] phenyl formamide as the metabolities. This result indicates that TOK undergose the reduction of its $NO_2\;to\;NH_2$ group, dechlorination, acetylation, and formylation under this condition. The cleavage of ether linkage does not occur. In addition, TOK degrades more readily in Chung Ju soil which is characterized by pH 6.43 and higher contents of $Ca^{++}$ and C.E.C. than in Chong Ju soil which is lower in pH, $Ca^{++}$, and C.E.C. 2. In the aerobic incubation of TOK of 25ppm in Chung Ju soil suspension for 21 days, the ratio of the resulting metabolites, TOK : amino-TOK : 4-Chloro-4'-amino diphenyl ether was 100 : 130 : 76. Meanwhile, in the 42 day incubation, the ratio was 100 : 19 : 5, which indicates that TOK in aerobic condition dose not necessrily degrade as a function of the incubation period. 3. The citrate buffer extract of Chung Ju soil has the capability of degrading TOK, which was verified to be due to the action of the microorganisms involved. 4. Twelye strains of soil bacteria were isolated from the TOK-treated soils. In the incubation of TOK in pure cultures of the respective isolates, the strain T-1-1 isolated from Chong Ju soil had almost no degradability whereas the strain T-2-3 was the most potent. The degradation of TOK by the isolates constituted mostly the reduction of the nitro group to amino group. 5. In a test for the degradability of TOK by some selected microorganisms, Pseudomonas species were more potent than fungi. Yet, Isolate B which had been isolated from Chung Ju soil suspension was the most potent.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7055-7059
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• 2014

Artemisia, as one of the largest genera in the tribe Anthemideae of the Asteraceae comprises an important part of Iranian flora. While cytotoxic and apoptotic properties have already been reported for some species of the genus there is not any report on cytotoxic effects of A. ciniformis. Petroleum ether (40-60), dichloromethane, ethyl acetate, ethanol and ethanol-water (50:50) extracts of the aerial parts of A. cinformis were subjected to cytotoxic and apoptotic evaluations on two cancer human cell lines (K562 and HL-60) and on J774 normal cells. Among multiple extracts evaluated for cytotoxicity, dichloromethane ($CH_2Cl_2$) and petroleum ether (PE) extracts were shown to possess the highest anti-proliferative effects on HL-60 and K562 cells with $IC_{50}$ values of 31.3 and $25.5{\mu}g/ml$ respectively. Apoptosis induction verified by sub-G1 peaks was seen in flow cytometry histograms. Increase in the amount of Bax protein, formation of DNA fragments, and cleavage of PARP to 24 and 89kDa sub units all confirmed induction of apoptosis by A. cinformis extracts. Taken together according to the result of the present study some extracts of A. cinformis could be considered as sources for natural cytotoxic compounds and further mechanistic and phytochemical studies are recommended to fully understand the underlying mechanisms of cnacer cell death as well as identification of responsible phytochemicals.