• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1520-1524
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• 2005

This paper describes the racemic and stereoselective synthetic route for a novel 4'$\alpha$-phenyl and 6'$\alpha$-methyl doubly branched carbocyclic nucleosides from an acyclic 2-hydroxy acetophenone. The installation of phenyl group at the 4'-position of carbocyclic nucleoside was successfully accomplished via a sequential [3,3]-sigmatropic rearrangement. The stereoselective introduction of a methyl group in the 6'$\alpha$-position was accomplished by Felkin-Anh controlled alkylation. Bis-vinyl 11 compound was successfully cyclized using a Grubbs’ catalyst II to desired carbocycles. The natural bases (adenine and cytosine) were efficiently coupled using a Pd(0) catalyst. Although all the synthesized compounds were examined for their activity against several viruses such as HIV-1, HSV-1, HSV-2 and HCMV, only cytosine analogues 17 exhibited weak antiviral activity against HCMV.

• Proceedings of the Korean Fiber Society Conference
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• 1996.10a
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• pp.468-472
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• 1996

A series of UV-curable polyurethane acrylate ionomer were synthesized from isophorone diisocyanate(IPDI), poly(tetramethylene ether glycol)(PTMG), 2,2-bis(hydroxymethyl)propionic acid (CMPA), triethylamine(TEA), 2-hydroxy ethyl acrylate (HEA), and dibutyl tin dilaurate (DBT) as a catalyst. 2,2-dimethoxy-2-phenyl acetophenone(DMPAP) was used as a photoinitiator. The films of UV-cured polyurethane acylate ionomer were prepared by casting the formulated materials onto a glass plate at room temperature and cured using a medium pressure mercury lamp (80 W/cm, max = 365nm). Effects of DMPA content, molecular weight of PTMG and degree of neutralization on the properties were invesigated. It is found that the storage modulus increased with increasing DMPA content. The glass transition temperature of sample A shifted to higher temperature as the content of DMPA was increased. Tensile modulus also increased with increasing DMPA content. Modulus and Tg decreased with increasing molecular weight of PTMG form 650 to 2000. With increasing the degree of nutralizaion, ionomers exhibited improved modulu.

• Bulletin of the Korean Chemical Society
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• v.21 no.1
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• pp.105-109
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• 2000

High-performance liquid chromatography is suitable for getting thermodynamic information about solute-solvent interactions. We used a squalane impregnated $C_{18}$ phase as a presumably bulk-like stationary phase to secure a simple partition mechanism for solute retention in reversed phase liquid chromatographic system. We measured retention data of some selected solutes (benzene, toluene, ethylbenzene, propylbenzene, butylbenzene, phenol, benzylalcohol, phenethylalcohol, benzylacetone, acetophenone, benzonitrile, benzylcyanide) at 25, 30, 35, 40, 45, and 50 $^{\circ}C$ in 30/70, 40/60, 50/50, 60/40 and 70/30 (v/v%) acetonitrile/water eluents. The van't Hoff plots were nicely linear, thus we calculated dependable thermodynamic values such as enthalpies and entropies of solute transfer from the mobile phase to the stationary phase based on more than four retention measurements on different days (or weeks). We found that the cavity formation effect was the major factor in solute distribution between the mobile and stationary phases in the system studied here. Our data were com-pared with some relevant literature data.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1080-1084
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• 1994

Asymmetric inducing effects of substituents attached at nitrogen, the 5-position and boron in oxazaborolidine rings on asymmetric borane reduction of ketones were investigated. Thus, the effect of N-substituents examined with the oxazaborolidines prepared from (lR,2S)-N-alkyl norephedrine derivatives showed the remarkable decrease of enantioselectivities of the product alcohols by the variation of the steric size of alkyl groups on nitrogen from Me${\leftrightarro}$n-Bu(${\simeq}$Bn)${\leftrightarro}$ neopentyl${\leftrightarro}$i-Pr, such as 83${\%}$ ee with 5b, 22${\%}$ ee with 5c, 23${\%}$ ee with 5f, 16${\%}$ ee with 5e, and 3${\%}$ ee with 5d for the reduction of acetophenone. The presence of diphenyl groups at the 5-position enhanced the enantioselectivities dramatically. The effect of B-alkyl substituents in the oxazaborolidines derived from (lR,2S)-ephedrine showed that the enantioselectivities of product alcohols decreased gradually when the substituents were changed from hydrogen to steric bulky groups such as methyl, n-butyl, thexyl and phenyl.

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.662-665
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• 1991

In order to prepare new chiral borohydrides (4) possessing chirality on dialkyl moieties, a series of B-alkoxydiisopinocampheylborinates (3) were synthesized by treatment of diisopinocampheylborane ($Ipc_2BH$) with alcohols (R in ROH: Me, Et, i-Pr, t-Bu) and reacted with excess of potassium hydride. Of these chiral borinic esters, only B-methoxydiisopinocampheyl borinate (3a) was converted into the corresponding dialkylmonoalkoxyborohydride (4a). For the other borinic esters, hydride uptake reactions were very slow at room temperature, accompanying disproportionation products at $65^{\circ}C$. The hydride (4a) formed is stable at $0^{\circ}C$ and can be stored over potassium hydride for few months. In the asymmetric reduction of the selected ketones, 4a provided the corresponding alcohols, such as 21% ee for 3-methyl-2-butanone, 11% ee for 2,2-dimethylcyclopentanone, 24% ee for acetophenone, 32% ee for 3-acetylpyridine, 30% for methyl benzoylformate, 31% ee for 4-phenyl-3-butyn-2-one, 39% ee for 3-butyn-2-one, and 34% ee for 3-hexyn-2-one.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.211-214
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• 1987

Asymmetric reduction of a series of aliphatic ketones and representative other classes of ketones with potassium 9-O-isopinocampheyloxy-9-boratabicyclo[3.3.1]non ane (K 9-O-Ipc-9-BBNH) was studied. All the ketones examined were reduced smoothly to the corresponding alcohols in THF at -$78^{\circ}C$. Thus, the reduction of 2-butanone, 3-methyl-2-butanone, 3,3-dimethyl-2-butanone, 2-octanone, and 4-phenyl-2-butanone provides 51% ee, 61% ee, 44% ee, 35% ee, and 33% ee of optical inductions, respectively. The reduction of other classes of ketones gave 52% ee for 2,2-dimethylcyclopentanone, 47% ee for acetophenone, 23% ee for 3-acetylpyridine, 50% ee for methyl benzoylformate, 4.8% ee for 2-chloroacetophenone, 30% ee for trans-4-phenyl-3-butene-2-one, and 2% ee for 4-phenyl-3-butyn-2-one. Thus, the reagent was found to be most useful in the asymmetric reduction of acyclic and cyclic aliphatic series of ketones.

• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.276-280
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• 1987

Several chiral potassium B-alkyl-9-boratabicyclo[3.3.1]nonanes $(K\; B-R^*-9-BBNH)$ and potassium B-alkoxy-9-boratabicyclo[3.3.1]nonanes $(K \;B-OR^*-9-BBNH)$ were synthesized by treatment of the corresponding trialkylboranes and dialkylmonoalkoxyboranes with a small excess of potassium hydride. The chiral B-alkoxy derivatives generally reduce representative ketones, such as acetophenone and 3-methyl-2-butanone, with greater optical induction than the corresponding B-alkyl derivatives, suggesting the involvement of the oxygen atom in the control process for asymmetric synthesis.

• Bulletin of the Korean Chemical Society
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• v.9 no.3
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• pp.164-166
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• 1988

7-Dithiocarboxy-3-phenyl-5,6-dihydro imidazo[2,1-b]thiazolium-betaine (2) was prepared by treatment of 3-phenyl-5,6-dihydro imidazo[2,1-b]thiazole (1) with carbon disulfide in acetone at room temperature. On the reaction of 2 with para-substituted phenacyl bromides (4) having the electron withdrawing property by virtue of (+) resonance (R) < (-) inductive (I) or (-) resonance (R), (-) inductive (I) effect, ring transformation product p-substituted-2-[2-[7-(p-substituted benzoyl)-5-thioxo-2,3-dihydro-1H-imidazo[1,2-c] thiazol-1-yl]-2-phenylvinylthio] acetophenone (6) was obtained; however, when R is electron donating grops with (+) resonance (R) > (-) inductive (I) effect the quarternary ammonium salt 7-(p-substituted phenyl) carbonyl methyl-3-phenyl-5,6-dihydro imidazo [2,1-b] thiazolium bromide (8) is formed. The reaction of 2 with unsubstituted-phenacyl bromide (R = H), on the other hand, gives 6a and 8a to the similar ratio, respectively.

• Natural Product Sciences
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• v.28 no.2
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• pp.62-67
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• 2022

Column chromatographic fractionation of the methanol and ethyl acetate extracts of the stem-bark of Anacardium occidentale led to the isolation of five compounds (1-5). Their structures were determined by spectroscopic means by comparing spectral data to be β-sitosterol (1), 2,4-dihydroxy acetophenone (2), 1-monolinolein (3), ethyl oleate (4) and β-sitosterol-3-O-β-D-glucopyranoside (5). These compounds were evaluated for cytotoxicity against human cancer cell lines: A549, SCOV3 and rat normal cell line NRK49f. Compounds 2-5 were for the first time isolated from A. occidentale.

• Korean Journal of Medicinal Crop Science
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• v.12 no.3
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• pp.255-261
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• 2004

The MeOH extracts from 21 species were tested for their cytotoxicity against SK-MEL-28 melanoma cell line and HaCat normal cell line in 5 g/ml by sulforrhodamine-B (SRB) method. Among them, the MeOH extract from Moutan Cortex Radicis showed the moderate activity with the growth rate of 74.3% in SK-MEL-28 cells and the high activity with the growth rate of 207.8% in HaCat cells. Activity-guided fractionation was performed and five compounds, paeonol (1), benzoylpaeoniflorin (2), benzoic acid (3), 2,5-dihydroxy-4-methoxy- acetophenone (4), paeonfliorin (5) were isolated from hexane and EtOAc fraction. The structures were established by physicochemical and spectrometric methods $(mp,\;UV,\;IR,\;^1H-NMR,\;^{13}C-NMR,\;spectram)$. All compounds were evaluated for their cytotoxicity, compound 4 showed the significant cytotoxic activity with $ED_50$ value of $5.92\;{\mu}g/ml$, but the other compounds no activity. These results suggest that compound 4 is a novel anticancer candidate against SK-MEL-28 melanoma cells.