• Bulletin of the Korean Chemical Society
• /
• v.30 no.4
• /
• pp.829-836
• /
• 2009

The catalytic enantioselective electrophilic fluorinations of active methine compounds promoted chiral palladium complexes have been developed. Treatment of $\beta$-keto phosphonates and $\beta$-ketoesters with N-fluorobenzenesulfonimide as the fluorine source under mild reaction conditions afforded the corresponding $\alpha$-fluorinated adducts in high yields with excellent enantiomeric excesses (up to 99% ee). These reactions can be conducted in alcoholic solvents without any precaution to exclude water and moisture.

• Journal of the Korean Chemical Society
• /
• v.33 no.6
• /
• pp.596-600
• /
• 1989

The simple and mixed ligand complexes of cadmium-oxalate-citrate systems have been studied with differential pulse polarography at 25${\circ}$C, in the solution with constant ionic strength, ${\mu}$= 1.0 ($NaNO_3$) and pH 8.0. Using the graphical methods by DeFord-Hume and Schaap-McMasters, the overall stability constants for the mixed ligand complexes, $\beta_{ij}$, were found to be: $log\beta_{11}$ = 4.91, $log\beta_{12}$ = 4.99, and log $log\beta_{21}$ = 5.18, respectively. Various equilibria involved in the mixed system have also been discussed.

• KSBB Journal
• /
• v.19 no.4
• /
• pp.321-326
• /
• 2004

Microparticles of an inclusion complex between itraconazole and 2-hydroxypropyl-${\beta}$-cyclodextrin (HP-${\beta}$-CD) were prepared using an environmentally-benign supercritical anti-solvent (SAS) process. In order to evaluate the degree of complexation, the thermal behavior of solid micro particulate complexes was investigated using differential scanning calorimetry. The experimental results obatined for the solubility and dissolution rate of the microparticulate inclusion complexes in a buffer solution of pH 1.2 showed that the complexation of itraconazole with HP-${\beta}$-CD results in a significant increase in the solubility and dissolution rate of itraconazole. For the microparticulate itraconazole/Hp-${\beta}$-CD inclusion complexes prepared by the SAS process, about 80% of itraconazole was found to dissolve in the buffer solution. Our experimental results confirmed that the SAS process is a promising method for the preparation of microparticles of water-insoluble drug/cyclodextrin inclusion complexes.

• Journal of the Korean Chemical Society
• /
• v.25 no.4
• /
• pp.228-235
• /
• 1981

Ultraviolet spectrophotometric investigation were carried out on the systems of pyridine, ${\beta}$-picoline and 3,5-lutidine with iodine in carbon tetrachloride. The results reveal the formation of one to one molecular complexes of the type, $C_5H_5N{\cdot}I_2$, ${\beta}-C_5H_4(CH_3)N{\cdot}I_2$ and 3,5-$C_5H_3(CH_3)_2N{\cdot}I_2$. The equrilibrium constants of complexes were obtained in consideration of that absorption maxima have the blue shift with the increasing temperatures according to the formation of the charge transfer complexes. The thermodynamic parameters, ${\Delta}H$, ${\Delta}G$ and ${\Delta}S$ for the formation of the charge transfer complexes were calculated from these values. These results indicated that the relative stabilities of the pyridine, ${\beta}$-picoline and 3,5-lutidine complexes with iodine increase in the order, pyridine < ${\beta}$-picoline < 3,5-lutidine. These results were supposed to be the influence resulted from increase of electron density by the positive inductive effect and the dipole moment of the steric hindrance effect. And this results were compared and discussed with polymethylbenzene-iodine CT-complexes.

• Archives of Pharmacal Research
• /
• v.18 no.1
• /
• pp.22-26
• /
• 1995

The solubility and dissolution rate of naproxen (NPX) complexed with 2-hydroxypropyl-.betha.-cyc-lodextrin (2-HP.betha.CD) using coprecipitation, evaporation, freeze-drying and kneading method were investigated. Solubility of NPX linearly increased (correlation cefficient, 0.995) as $2-HP\betaCD$ concentraction increased, resutling in $A_l$ type phase solubility curve. Inclusion complexes prepared by four different methods were compared by different methods were compared by dfferential scanning calorimetry(DSC). The NPX showed sharp endothemic peak around $156^{\circ}C$ but inclusion complexes by evaporation, freeze-drying and kneading method showed very broad peak without distinct phase transtion temperature. In contrast, inclusion complex prepared by coprecipitation method resulted in detectable peak around $156^{\circ}C$ which is similar to NPX, suggesting incoplete formation of indusion co plex. Dissolution rate of inclusion complexes prepared by evaporation, frezz-drying and kneding except coprecipitation method was largely enhanced in the simultaed gastric and intestinal fluid when compared to NPX powder and commercial $NA-XEN^\registered$tablet. However, about 65% of NPX in gstric fluid. in case of inclusion complex prepared by coprecipitation method, formation of inclusion complex appeared to be incoplete, resulting in no marked enhancement of dissolution rate. From these findings, inclusion complexes of poorly water-soluble NPX with $2-HP\betaCD$ were useful to increase soubility and dissolution rate, resting in enhancement of bioavailability and minimization of gastrointestinal toxicity of drug upon oral administration of inclusion complex.

• YAKHAK HOEJI
• /
• v.47 no.4
• /
• pp.200-205
• /
• 2003

The stability constants for the inclusion complexes between carboxymethyl-$\beta$-cyclodextrin (CM-$\beta$-CD) and five $\beta$-blockers, such as atenolol (ATE), bisoprolol (BIS), metoprolol (MET), pindolol (PIN) and propranolol (PRO) were determined by capillary electrophoresis. The magnitude of stability was decreased as following order; PRO＞MET＞BIS＞ATE＞PIN. Among them PRO showed the highest affinity towards CM-$\beta$-CD with stability constants of 383 and 371 $M^{-l}$ for (R)- and (S)-enantiomer, respectively. PIN enantiomers showed the lowest stability towards CM-$\beta$-CD, while the selectivity between (R)- and (S)-enantiomer was higher than any other tested $\beta$-blocker.r.

• Polymer(Korea)
• /
• v.39 no.2
• /
• pp.261-267
• /
• 2015

The inclusion complexes (ICs) between polylactic acid (PLA) and ${\beta}$-cyclodextrin (CD) were prepared by co-precipitation method in this work. The orthogonal experiments were designed to investigate the influence of different factors on the formation of inclusion complexes. The results suggested that the optimum scheme of inclusion compounds could be obtained when the feeding ratio of CD to PLA (wt%) was 20:1, stirring speed was 6 kr/min and the stirring time was 30 min. The structures and properties of the inclusion complexes were characterized by $^1H$ NMR, FTIR, DSC, FT-Raman, XRD and TGA. The DSC results demonstrated that the crystallization behavior of the inclusion complexes nearly disappeared. It was found that ${\beta}$-CD-PLA inclusion complex had a better thermal stability compared with the neat PLA. The model of the inclusion complexes was proposed on the basis of XRD, $^1H$ NMR and DSC results.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.2
• /
• pp.216-220
• /
• 2004

${\beta}$-CD and CM- ${\beta}$-CD as chiral NMR shift agents were used to resolve the enantiomers of noradrenaline (NA). The stoichiometry of each complex formed between the CDs and the enantiomers of NA was found to be 1 : 1 through the continuous variation plots. The binding constants (K) of the complexes were determined from $^1H$ NMR titration curves. This result indicated that both ${\beta}$-CD and CM- ${\beta}$-CD formed the complexes with the S(+)-NA more preferentially than its R(-)-enantiomer. The K values for the complexes with ${\beta}$-CD ($K_{S(+)}$ = 537 $M^{-1}$ and $K_{R(-)}$ = 516 $M^{-1}$ was larger than those with CM- ${\beta}$-CD ($K_{S(+)}$ = 435 $M^{-1}$ and $K_{R(-)}$ = 313 $M^{-1}$), however, enantioselectivity (${\alpha}$) of S(+)- and R(-)-NA to CM- ${\beta}$-CD ( ${\alpha}$ = 1.38) was larger than that to ${\beta}$-CD ( ${\alpha}$ = 1.04), indicating that CM- ${\beta}$-CD was the better chiral NMR solvating agents for the recognition of the enantiomers of NA. Two dimensional rotating frame nuclear Overhauser enhancement spectroscopy (ROESY) experiments were also performed to explain the binding properties in terms of spatial fitting of the NA molecule into the macrocyclic cavities.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.10
• /
• pp.2213-2216
• /
• 2009

A novel carbazole functionalized bis-$\beta$-diketone type organic ligand, 1,1′-(2,6-bispyridyl)bis-3-(9-ethylcarbazole- 3-yl)-1,3-propanedione ($H_2L$) and its corresponding lanthanide complexes $Eu_2(L)_3\;and\;Tb_2(L)_3$ were successfully prepared. The ligand and complexes were characterized in detail based on FT-IR spectra, $^1H$ NMR and elemental analysis. The observed UV-Vis absorption and photoluminescence properties of the complexes were investigated, it shows that the Eu(III) and Tb(III) ions can be sensitized efficiently by the ligand ($H_2L$) to some extent, in particular, the complex $Tb_2(L)_3$ exhibits a more excellent luminescence property than the Eu(III) complex. Meanwhile, the introduction of the carbazole moiety can enlarge the $\Pi$-conjugated system of the ligand and enhance the luminescent intensity of the complexes. The results show that the complexes would be used as excellent luminescent materials.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.11
• /
• pp.6949-6953
• /
• 2013

Background: Nowadays, the encapsulation of cytotoxic chemotherapeutic agents is attracting interest as a method for drug delivery. We hypothesized that the efficiency of helenalin might be maximized by encapsulation in ${\beta}$-cyclodextrin nanoparticles. Helenalin, with a hydrophobic structure obtained from flowers of Arnica chamissonis and Arnica Montana, has anti-cancer and anti-inflammatory activity but low water solubility and bioavailability. ${\beta}$-Cyclodextrin (${\beta}$-CD) is a cyclic oligosaccharide comprising seven D-glucopyranoside units, linked through 1,4-glycosidic bonds. Materials and Methods: To test our hypothesis, we prepared ${\beta}$-cyclodextrin-helenalin complexes to determine their inhibitory effects on telomerase gene expression by real-time polymerase chain reaction (q-PCR) and cytotoxic effects by colorimetric cell viability (MTT) assay. Results: MTT assay showed that not only ${\beta}$-cyclodextrin has no cytotoxic effect on its own but also it demonstrated that ${\beta}$-cyclodextrin-helenalin complexes inhibited the growth of the T47D breast cancer cell line in a time and dose-dependent manner. Our q-PCR results showed that the expression of telomerase gene was effectively reduced as the concentration of ${\beta}$-cyclodextrin-helenalin complexes increased. Conclusions: ${\beta}$-Cyclodextrin-helenalin complexes exerted cytotoxic effects on T47D cells through down-regulation of telomerase expression and by enhancing Helenalin uptake by cells. Therefore, ${\beta}$-cyclodextrin could be superior carrier for this kind of hydrophobic agent.