• Bulletin of the Korean Chemical Society
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• v.29 no.7
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• pp.1327-1331
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• 2008

Novel $CO_2$-soluble 8-hydroxyquinoline (8-HQ) chelating agents were synthesized and evaluated for solubility and metal ion extraction ability in supercritical $CO_2\;(Sc-CO_2)$. Among them, secondary amide-containing 8- HQ derivatives cannot be dispersed well into Sc-$CO_2$, but tertiary amide-containing derivatives can dissolve completely in Sc-$CO_2$ even at low CO2 pressures, perhaps owing to the predominant intermolecular interaction between the chelating agent and the $CO_2$ molecule. Based on 8-HQ chelating agent solubility data, we investigated the extraction of metal ions ($Co^{2+}$, $Cu^{2+}$, $Sr^{2+}$, $Cd^{2+}$, and $Zn^{2+}$) using two highly $CO_2$-soluble 8-HQ derivatives (4d, 4e) in Sc-$CO_2$. The extraction efficiency of tertiary amide-containing 8-HQ ligands, both fluorinated and non-fluorinated forms, was dramatically increased in the presence of diethyl amine (organic base). We suggest that diethyl amine could play an important synergistic role in the stronger metal binding ability of 8-HQ through an in situ deprotonation reaction in Sc-$CO_2$ medium.

• Journal of Pharmaceutical Investigation
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• v.34 no.6
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• pp.453-457
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• 2004

Atenolol and related compounds found in raw materials and commercial products were analyzed by reversed-phase high-performance liquid chromatography. A mixed solution of phosphate buffer (3.4 g/l, pH 3.0), tetrahydrofurane and methanol (800:20:180, v/v/v) including sodium octanesulfonate (1 g/l) and tetrabutylammonium-hydrogensulfate (0.4 g/l) was used as mobile phase at the flow rate of 0.25 ml/min. Detection was carried out at UV 226 nm. Atenolol related compounds, such as bis ether, tertiary amine and blocker acid were identified by comparing the retention time of the standard. The within-day and between-day precisions of the separated compounds were less than 1.2% and 3.4%, respectively. The contents of related compounds of the tested samples were under the limit prescribed in the European Pharmacopoeia. The pattern of the related compounds showed that atenolol raw materials and products could be classified in three different groups, indicating that the materials originated from different source or treated in different way.

• Korean Journal of Environmental Agriculture
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• v.14 no.1
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• pp.55-71
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• 1995

Wheat (Triticum aestivum L.) seeds were used to study a possible relationship between strontium and polyamines (PAs) in the coleoptile, root, and endosperm during germination. When $Sr^{2+}$ (0.001 mM + 10 mM) was applied to the incubation medium with $10\;{\mu}M$ $GA_3$, great increases in putrescine (Put) were observed in root and spermidine (Spd) in the coleoptile, depending on the concentration. In germinating seeds, putrescine accumulation was induced even at a low concentration (0.01 mM Sr), whereas spermidine accumulation was stimulated considerably at a high concentration (10 mM Sr). The putrescine levels, on a gram fresh weight (g-fr-wt) basis, in the roots which were growth-inhibited by 1 and 10 mM $Sr^{2+}$ were 22.4 and 15.3 fold higher respectively than at the same concentrations of $Ca^{2+}$. The accumulation of total polyamine (TA), in particular Put and Spd, induced by Sr seemed to be an important physiological response not only on a g fr wt basis but also on an RNA basis. In contrast, the levels of agmatine (Agm) and cadaverine (Cad) were notably enhanced by 10 mM $Ca^{2+}$ in the coleoptile and root. Cadaverine was detected only in $Ca^{2+}-treated$ seedlings. However, $Ca^{2+}-treatment$ in the range of 0.001 mM to 1.0 mM resulted in reduction of TA content. The distinction of accumulated polyamines and the change in diamine (DA) / TA and tri- and tertiary (tPA) / TA ratios were likely to be a physiological difference between $Sr^{2+}$ and $Ca^{2+}$ during germination in wheat.

• Journal of the Korean Chemical Society
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• v.19 no.5
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• pp.343-350
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• 1975

About 20${\sim}$100${\mu}g$ iridium have been extracted quantitatively as stannous-chloro Complex from aqueous solution by Alamine-336, a high molecular weight tertiary amine, dissolved in benzene. The extractability was confirmed by radioactive tracer of iridium-192. The spectrophotometric measurements of the extracted species at 322.5 nm indicate the feasibility of this method to be used as an analytical procedure for the determination of micro amount of iridium. An anion model of stannous-chloro complex of iridium has been postulated to account for the extraction mechanism.

• Journal of the Korean Chemical Society
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• v.43 no.3
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• pp.294-301
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• 1999

Geminal bisphosphonates have been well known to be effective inhibitors of various calciumrelated disorders such as Paget's disease, hypercalcemia of malignancy, and osteoporosis. To synthesize bisphosphonates, we have used the pentacovalent oxaphospholene prepared from methyl vinyl ketone and triethyl-phosphite. Υ-Ketobisphosphonates are obtained by bromination, applied Westheimer reaction, and hydrolysis of synthesized oxaphospholene. This compound was converted to the N-alkylated Υ-aminobisphosphonates by the reductive amination. Conversion of the resulting secondary amine to the tertiary one, followed by introduction of the second alkyl group on the nitrogen, was led to the synthesis of new N,N'-dialkylated Υ-aminobisphosphonates.

• KSBB Journal
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• v.9 no.4
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• pp.406-411
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• 1994

An extractive fermentation process was developed to produce citric acid from g1ucose. Citric acid is a strong inhibitor to this fermentation. A mixture of tertiary amine and oleyl alcohol was used to selectively extract citric acid from the fermentation broth, hence enhancing the productivity by over 200%. Although the toxicity of the solvent was significant in the range of higher than 30% of amine, immobilization in polyurethane foam was useful to protect the cells from the toxicity of the solvent.

• YAKHAK HOEJI
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• v.35 no.3
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• pp.182-189
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• 1991

Systematic study on the extraction of ion pair by the use of picric acid (PCA) as an ion pair forming reagent to the aliphatic amines has not be done by spectrophotometric method. The extraction of ion pair by the use of PCA and 23 kinds of the aliphatic amines was examined. The procedure is as follows; Elving's buffer solution (pH 1.3~10, ionic strength 0.5) each amine solution, and PCA solution were taken into a test tube. The mixture was shaken mechanically with chlorform. The organic phase was filtered through a filter paper to remove water droplets. The absorbance was examined at $\lambda_{max}$ against a reagent blank. Primary and secondary whose carbon number were more than 7 or 6, respectively, are extractable as ion pairs with PCA, while tertiary amines and quaternary ammonium salts are also extractable without the correlation of carbon number. It was considered that the ion pair extraction of primary and secondary amines was affected by the number of carbon of amines, but its extraction of tertiary amines or quaternary ammonium salts was affected by kind of aliphatic amines rather than pKa values or carbon number of amines.

• Bulletin of the Korean Chemical Society
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• v.18 no.8
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• pp.890-895
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• 1997

The approximate rates and stoichiometry of the reaction of excess lithium tripiperidinoaluminum hydride (LTPDA), an alicyclic aminoaluminum hydride, with selected organic compounds containing representative functional groups under the standardized conditions (tetrahydrofuran, 25°) were examined in order to define the reducing characteristics of the reagent for selective reductions. The reducing ability of LTPDA was also compared with those of the parent lithium aluminum hydride (LAH) and lithium tris(diethylamino)aluminum hydride (LTDEA), a representative aliphatic aminoaluminum hydride. In general, the reactivity of LTPDA toward organic functionalities is weaker than LTDEA and much weaker than LAH. LTPDA shows a unique reducing characteristics. Thus, benzyl alcohol, phenol and thiols evolve a quantitative amount of hydrogen rapidly. The rate of hydrogen evolution of primary, secondary and tertiary alcohols is distinctive. LTPDA reduces aldehydes, ketones, esters, acid chlorides and epoxides readily to the corresponding alcohols. Quinones, such as p-benzoquinone and anthraquinone, are reduced to the corresponding diols without hydrogen evolution. Tertiary amides and nitriles are also reduced readily to the corresponding amines. The reagent reduces nitro compounds and azobenzene to the amine stages. Disulfides are reduced to thiols, and sulfoxides and sulfones are converted to sulfides. Additionally, the reagent appears to be a good partial reducing agent to convert primary carboxamides into the corresponding aldehydes.

• Bulletin of the Korean Chemical Society
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• v.15 no.10
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• pp.881-888
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• 1994

The approximate rates and stoichiometry of the reaction of excess sodium tris(diethylamino)aluminum hydride (ST-DEA) with selected organic compounds containing representative functional groups under standardized conditions(tetrahydrofuran, $0{\circ}$) were studied in order to characterize the reducing characteristics of the reagent for selective reductions. The reducing ability of STDEA was also compared with those of the parent sodium aluminum hydride (SAH) and lithium tris(diethylamino)aluminum hydride (LTDEA). The reagent appears to be milder than LTDEA. Nevertheless, the reducing action of STDEA is very similar to that observed previously for LTDEA, as is the case of the corresponding parent sodium and lithium aluminum hydrides. STDEA shows a unique reducing characteristics. Thus, benzyl alcohol, phenol and 1-hexanol evolved hydrogen slowly, whereas 3-hexanol and 3-ethyl-3-pentanol, secondary and tertiary alcohols, were essentially inert to STDEA. Primary amine, such as n-hexylamine, evolved only 1 equivalent of hydrogen slowly. On the other hand, thiols examined were absolutely stable. STDEA reduced aidehydes and ketones rapidly to the corresponding alcohols. The stereoselectivity in the reduction of cyclic ketones by STDEA was similar to that by LTDEA. Quinones, such as p-benzoquinone and anthraquinone, were reduced to the corresponding 1,4-dihydroxycyclohexadienes without evolution of hydrogen. Carboxylic acids and anhydrides were reduced very slowly, whereas acid chlorides were reduced to the corresponding alcohols readily. Esters and epoxides were also reduced readily. Primary carboxamides consumed hydrides for reduction slowly with concurrent hydrogen evolution, but tertiary amides were readily reduced to the corresponding tertiary amines. The rate of reduction of aromatic nitriles was much faster than that of aliphatic nitriles. Nitrogen compounds examined were also reduced slowly. Finally, disulfide, sulfoxide, sulfone, and cyclohexyl tosylate were readily reduced without evolution of hydrogen. In addition to that, the reagent appears to be an excellent partial reducing agent: like LTDEA, STDEA converted ester and primary carboxamides to the corresponding aldehydes in good yields. Furthermore, the reagent reduced aromatic nitriles to the corresponding aldehydes chemoselectively in the presence of aliphatic nitriles. Consequently, STDEA can replace LTDEA effectively, with a higher selectivity, in most organic reductions.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.246-248
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• 1988

The electrical insulation characteristics of the Epoxy resin is generally depended upon the cross-Link. Therefore, when the Epoxy is cured the full cross-Link must be gotten to obtain the best electrical insulation property. This paper alms at examining the cure condition to get the best cross-link. The Epoxy used in this experiment is DGEBA, the curing materiel is MNA, and the accellator is tertiary amine. In this study, the best curing condition of cross-link is suggested by analysing the each Epoxy resin which is differenty cured according Lo the variable temperatures and curing times.