• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.895-899
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• 2004

We have designed a new family of radioligands, 3-(amino- and hydroxymethyl)-4-(5-iodopyridin-2-ylthio)indoles, combining characteristically distinct moieties proven to impart successful binding ability in a variety of structurally diverse selective serotonin reuptake inhibitors recently published. Described in this article are the syntheses of 3-substituted 4-(5-iodopyridin-2-ylthio)-indoles, featuring successful adaptation of the modified Leimgruber-Batcho indole synthesis onto the key intermediate 1-(5-iodopyridin-2-ylthio)-2-methyl-3-nitrobenzene (6) prepared from the nucleophilic aromatic substitution of chloropyridine 7 with thiophenol 8.

• Bulletin of the Korean Chemical Society
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• v.24 no.11
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• pp.1671-1674
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• 2003

The effects of amine donors ($a:NH_2,\;b:NMe_2,\;c:NMePh,\;d:NPh_2$) and conjugation length on the molecular hyperpolarizabilities of a series of dipolar molecules have been theoretically investigated by using CPHF/6-31G method. The first hyperpolarizabilities (${\beta}$) of p-nitrobenzene derivatives increase with the donor in the order, $NH_2\;<\;NMe_2\;<\;NMePh\;<\;NPh_2$, whereas slightly different order is observed in more conjugated derivatives, i.e., $NH_2\;<\;NPh_2\;<\;NMe_2\;<\;NMePh$. The result has been attributed to the extent of charge transfer and torsion angle. Moreover, the results show that "non-traditional" ${\pi}$-conjugation effect exists in small compounds and decreases as the conjugation length between donor and acceptor increases.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.23-28
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• 2011

The pine wood meal was ozonated in acidic water. A 91.3% of lignin and 13% of polysaccharides in pine wood meal were degraded with 180 min ozonation. The phenolic hydroxyl groups of lignin in ozonated wood meals were increased with ozonation time. The vanillin content in nitrobenzene oxidation products of lignin is decreased with 10 min. ozonation and it was slightly increased with ozonation time. The sugar composition of ozonated wood meals showed that the hemicellulose was more susceptible to ozonation than cellulose. The crystallinity of ozonated wood meal was increased.

• Bulletin of the Korean Chemical Society
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• v.9 no.1
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• pp.52-55
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• 1988

Starting with readily available p-tert-butylcalix[4]arene 3 tert-butyl groups are removed by $AlCl_3$-catalyzed de-alkylation reaction, and the calix[4]arene 4 formed is converted into the tetraacyl esters. These compounds undergo Fries rearrangement to yield p-acylcalix[4]arenes. p-Acetyl, p-propionyl, p-butyryl, and p-benzoylcalix[4]arene 10, 11, 12 and 14 are synthesized in 70-80% yields by treatment of the corresponding esters 5, 6, 7 and 9 with $AlCl_3$ in nitrobenzene. When the tetraisobutyryl ester 8 was treated with the same condition, only two isobutyryl groups were rearranged to the para-positions of calix[4]arene, and remaining two groups were simply cleaved.

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.451-455
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• 1999

The polymerization of 2-ethynylpyridine by alkyl bromide carrying carbazole moiety, 6-(N-carbazolyl)hexyl bromide, relatively proceed well to give the corresponding poly[6'-(N-carbazolyl)hexyl-2-ethynylpyridinium bromide) in high yields under DMF reflux conditions without any initiator or catalyst. This polymerization was influenced upon the initial monomer concentration. The polymer yields and inherent viscosities of the resulting polymers were in the range of 34-85% and 0.11-0.21 dL/g, respectively. Instrumental analyses using NMR, IR, and UV-visible spectroscopies and elemental analysis indicated that the resulting polymer has a conjugated polymer backbone system carrying pyridine and n-hexyl carbazole moiety. The polymers were mostly brown powders and completely soluble in DMF, DMSO, nitrobenzene, and formic acid. The photoluminescence spectrum of the dilute polymer solution with the excitation at 383 nm exhibited two sharp peaks at 495 and 540 nm.

• Bulletin of the Korean Chemical Society
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• v.13 no.6
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• pp.599-605
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• 1992

Rate constants of methanolyses of para-Z-substituted benzenesulfonyl chlorides have been determined in various isodielectric solvent mixtures. A third-order kinetic behavior has been observed in the methanolysis of p-nitrobenzenesulfonyl chloride in methanol-nitromethane mixture from the correlation figure of logarithms of rate constants were plotted against Y-values based on solvolyses of 1-adamantyl tosylate. $S_N1$-$S_N2$ mixing mechanisms are favored by neutral or weak electron-donating and weak electron-withdrawing substituents of p-Z-substituted benzenesulfonyl chlorides in methanol-nitrobenzene mixture. While the methanolyses of para-Z-substituted benzenesulfonyl chlorides in methanol-ethylene glycol solvent mixture are appropriate for $S_N2$ mechanism from the mechanistic criterion by means of m-values.

• YAKHAK HOEJI
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• v.16 no.4
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• pp.180-185
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• 1972

A new spectrophotometric method was established for the determination of undecylenic acid. The method is based on the solvent extraction into nitrobenzene of the ion pair formed between tris(1,10-phenanthroline)Fe(II) chelate and the anion of undecylenic acid. The maximum absorbance of the extract in the organic phase was at 518nm. A maximum extraction was obtained at pH 9-11, when excess of at least 50-fold(molar) of the phenanthroline-Fe(II) chelate to undecylenic acid was present. The color intensity of the extracted species remained constant at room temperature for the several hours after separation of the organic layer. A linear relationship was obtained over the tested range of 5-20${\gamma}$/ml of undecylenic acid. The effect of several other fungicids on this method was investigated. The method was applied to the determination of undecylenic acid in preparations and the results were in good agreement with those added amounts.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.162-165
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• 1987

The reduction rate of borohydride exchange resin (BER) was greatly enhanced in the presence of lithium salts. Thus 2-heptanone was reduced completely with BER-LiCl in 1 h at room temperature. However, no reduction was observed with BER alone under the same conditions. With this system, organic compounds containing various fuctional groups were examined in ethanol at room temperature. This study revealed that BER-LiCl system exhibits an excellent chemoselectivity for carbonyl group in the presence of other functional groups. Keto esters and epoxy ketones were reduced with BER-LiCl to give the corresponding hydroxy esters and epoxy alcohols with excellent yields. Selective reductions of carbonyl groups were also possible in the presence of other organic compounds containing functional groups such as 1-idooctane, 1-bromooctane, caproamide, hexanenitrile, nitrobenzene, n-butyl disulfide, dimethyl sulfoxide and 1-dodecene.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.372-380
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• 2009

After supercritical water treatment of poplar wood meals (passed through 60 mesh) for 60s between 325 and $425^{\circ}C$ at the fixed pressure at $220{\pm}10atm$, some solid residues were present in the degradation products. They mainly consisted of chemically modified lignin and fibrous materials. Glucose and xylose were identified as main sugar components of fibrous materials, and the highest ratio of glucose/xylose was achieved at the highest reaction temperature. As reaction temperature was elevated, the portion of fibrous materials decreased in the solid residues, while lignin was further accumulated. The H : G : S ratio of lignin in solid residues was estimated by analytical pyrolysis. Irrespective of reaction temperatures, the H:G:S ratios were not significantly changed in the lignin in solid residues. Compared to poplar milled wood lignin (MWL), it was remarkable that H type monomers were further lowered, while portion of S type monomers increased. The amount of G type monomers were relative stable. In presence of HCl catalyst, lowering H type as well as enhancing S type was further distinguishable. According to the result of nitrobenzene oxidation (NBO), ca. 265 mg of vanillin and syringaldehyde was yielded from poplar MWL as main products. However, remarkably reduced amount of NBO products were determined from solid residues by raising operating temperature as well as by the addition of HCl catalyst. These results strongly indicate that $\beta$-O-4 linkage could be easily cleaved during supercritical water treatment, so that the lignins in the solid residues seem to be condensed phenol polymers, which are mainly formed by carbon-carbon linkages rather than $\beta$-O-4 linkage.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.230-237
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• 2004

In this study nitroreductase from Pseudomonas sp. HK-6 capable of degrading 2,4,6-trinitrotoluene (TNT) was characterized. Through a series of purification process including ammonium sulfate precipitation, DEAE-sepharose, and Q-sepharose, three different fractions I, II, and III having the enzyme activity of NTRs whose molecular weights were approximately 27 kDa were detected in fractions from HK-6 cells. Specific activity of the three fractions were approximately 4.85 unit/mg, 5.47 unit/mg, and 5.01 unit/mg, and concentrated to 9.0-, 10.1-, and 9.3-fold compared to crude extract, respectively. The optimal pH and temperature for the three NTR fractions were approximately 7.5 and $30^{\circ}C$, respectively. Metal ions, $Ag^{＋}$ , $Cu^{ 2+}$, $Hg^{2＋}$ inhibited approximately 70% of enzymes activities of all NTR, while $Fe^{2＋}$ did not stimulate or inhibit the activities. Monitoring the effect of chemicals on the enzyme activity revealed that those NTR fractions lost enzyme activity in presence of $\beta$-mercaptoethanol, but were a little influenced by dithiothreitol, EDTA and NaCl. The three NTR fractions demonstrated enzyme activities for nitrobenzene and RDX as well as TNT.