• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.327-327
• /
• 2006

Methyl glycidyl ether has been polymerized in a controlled fashion at low temperature in toluene using the combination of tetraoctyl ammonium bromide and triisobutyl aluminum. Poly(glycidyl methyl ether)s with molar masses ranging from 3 000 to about 90 000 g/mol and narrow polydispersities (<1.2) were prepared and the dependence of their solubility and LCST in water as a function on their molar masses investigated.

• Journal of the Korean Chemical Society
• /
• v.9 no.4
• /
• pp.211-214
• /
• 1965

The partition function of liquid methyl chloride and methyl bromide are developed by applying the significant structure theory of liquid.$^{(1-3)}$ The parameters therein are determined by the modified significant structure theory of liquid.$^{(4)}$ The molar volume, the vapor pressure, and the entropy of vaporization of the liquids are calculated over a wide temperature range. The critical properties for the liquids are also calculated. The results show good agreement with experimental observations.

• Bulletin of the Korean Chemical Society
• /
• v.8 no.1
• /
• pp.15-19
• /
• 1987

Preparation of optically pure (3R, 4R)-4-acetoxy-3-[(1R)-1-hydroxyethyl]azetidin-2-o ne derivatives, which can be employed as starting materials for synthesis of carbapenem and penem antibiotics, was established in high efficiency from 6-amino-penicillanic acid (6-APA). 6-APA was diazotized and brominated to give 6, 6-dibromopenicillanic acid and its methyl ester was metalated with methylmagnesium bromide and condensed with acetaldehyde. The product, methyl 6-bromo-6-(1-hydroxyethyl)penicillanate was reduced with Zn-$NH_4Cl-NH_4OH$-acetone efficiently to give methyl 6-(l-hydroxyethyl)-penicillanate, which was protected either with ${\beta},{\beta},{\beta}$ -trichloroethoxycarbonyl group or with t-butyldimethylsilyl group. The thiazolidine rings of these compounds were cleaved by treatment of mercury(II) acetate in acetic acid and permangante in acetone in sequence to afford the desired optically pure final products.

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

• Journal of Biomedical Engineering Research
• /
• v.9 no.2
• /
• pp.225-232
• /
• 1988

Poly (L- lactic acid-co-glycine-L-lactic acid) and Poly (L-lactic acid-co-glycine-L- methyl lactic acid ) have been prepared by ring opening polymerization. The monomer 6, 6-dimethyl morpho-line-2, 5-dione was synthesized by the bromoisobutylation of 2-bromoisobutyryl bromide with glycin e. L-lactide, 6-methyl morpholine-2, 5-diode. and 6, 6-dimethyl morpholine-2, 5-diode have been used as starting materials for polydepsipeptides. The synthesized monomers and copolymers have been identified by NMR and FT-lR spa- ctrophotometer. The thermal propert ies and glass transition temperature(Tg) of the copolymers have been measured by differential scanning calorimetry. The Tg values of poly(L-lactic acid co-glycine-L-lactic acid) system are increased from $53^{\circ}C\; to\; 107^{\circ}C$ with increasing the mole fraction of 6-methyl morpholine-2, 5-diode. And the Tg values of poly(L-lactic acid co-glycine-L-methyl lactic acid) system are increased from $53^{\circ}C\;to\;138^{\circ}C$ with increasing the mole fraction of 6. 6-dimethyl morpholine-2, 5-diode The thermal stability of poly (L-lactic acid-co-glycine-L-methyl lactic acid) is slightly greta text than that of poly(L-lactic acid-co-glycine-L-lactic acid) due to the methyl group.

• Horticultural Science & Technology
• /
• v.16 no.3
• /
• pp.374-376
• /
• 1998

Effects of traditional fumigation (methyl bromide; MB) and combined fumigation (methyl bromide/phosphide; $MB/PH_3$) on the disinfestation, and phytotoxicity and longevity of cut flowers (lily and rose) were investigated. Combined fumigation with low concentrations of $7/3g/m^3\;(MB/PH_3$) at $10^{\circ}C$ immediately after transportation from harvested place was found to be much more effective in disinfestation of aphid, mite, and thrips than fumigation with $MB\;48g/m^3$ only at $20^{\circ}C$ after simulated transportation for 2 days. Quality and longevity of cut flowers measured after fumigation were better in flowers treated by combined fumigation ($7/3g/m^3,\;MB/PH_3$) at $10^{\circ}C$ for 2.5-3 hrs, irrespective of pretreatment with pulsing solution immediately after transporation, even though phytotoxicity varied with cut flowers fumigated. On the other hand, fumigation with $MB\;48g/m^3$ only at $20^{\circ}C$ after simulated transportation for 2 days showed tendency of enhanced insect disinfestation, but caused phytotoxicity to both lily and rose, regardless of pretreatment and moreover, reduced the longevity of the cut flowers.

• Horticultural Science & Technology
• /
• v.16 no.3
• /
• pp.370-373
• /
• 1998

Fumigation by combination of methyl bromide/phosphide ($MB/PH_3$) was much more effective in disinfestating the rose insect pests (Aphis gossypii, Tetranychus urticae, and Frankliniella occidentalis) than that by individual MB or $PH_3$. Fumigation for 2 hours in the chamber using ;$MB/PH_3$ at the concentration of $10/3g{\cdot}m^{-3}$ brought about 91.3% and 100% mortality in aphids and thrips, respectively. Fumigation for 3 hrs using ;$MB/PH_3$ at the concentration of 5/3 or $7/3g{\cdot}m^{-3}$ showed over 96% mortalities in mites and thrips as well as no phytotoxicity symptoms, e.g. tip burn or bent neck, in cut roses, while mortalities of mites and thrips were not influenced by increasing $CO_2$ concerntration from 0.03% to 10% or decreasing $O_2$ concentration up to 15% in fumigation chamber.

• Horticultural Science & Technology
• /
• v.16 no.3
• /
• pp.366-369
• /
• 1998

To lesson economical loss induced by fumigation in importing country when cut roses are exported, effects of several fumigation temperature, treatments of cut stems (dry or wet), methyl bromide (MB) concentrations, and fumigation periods on the quality of cut roses were investigated. According to results, the most important factor affecting the quality of cut rose was found to be fumigation temperature. When fumigated at $5^{\circ}C$, cut roses showed no chemical damages, e.g., tip burn or bent neck, and maintained their quality for the same duration as that of control, regardless of MB concentrations or treatments of cut stems. However, phytotoxicity by MB increased and vase life of cut rose was shortened as fumigation temperature increased. Timing of fumigation also appeared to be an important factor affecting the quality of cut roses of which phytotoxicity by MB was not observed and thier vase life was not shortened, even if MB was treated up to $40g{\cdot}m^{-3}$, when cut roses were fumigated at $5^{\circ}C$ on the day of harvesting. On the other hand, the degree of damage of cut flowers by fumigation methods or MB concentraions was not consistent with changes in fumigation temperature.

• Journal of Korean Society of Archives and Records Management
• /
• v.1 no.1
• /
• pp.231-243
• /
• 2001

The sterilization method of records by fumigation using mixed gas of methyl bromide(MB) and ethylene oxide(ETO) has been generally used as a way to protect biological deterioration by microorganisms and insects. In this study, we confirmed sterilization effect of MB and ETO [86 : 14(Vol.%)] on and analyzed toxicity on microorganisms isolated from records. To analyze sterilization effect of fumigation on microorganisms and insect, we have fumigated microorganisms and insect with a various amounts mixed gas of MB and ETO, and various exposure time. Insect was sterilized at all experimental conditions. In microorganisms, sterilization effect was detected only when the mixed gas was treated at $120g/m^3$ concentration for at least 24 hrs. To test the possibility of isolated microorganisms as a threat to human health, it was investigated that toxicity test using yeast, radish and cancer cells on microorganisms. Only Aspergillus oryzae had an inhibition effect on growth of yeast. radish and cancer cells, respectively. These results demonstrate that sterilization effect can occur at low concentrations of the mixed gas on insect but requires higher concentrations of the mixed gas on microorganisms. In addition to, it is suspected that the possibility of the microorganism as a threat to human health is little.

• Archives of Pharmacal Research
• /
• v.28 no.10
• /
• pp.1105-1110
• /
• 2005

Novel anomeric branched carbocyclic nucleosides were synthesized from 1,3-dihydroxy acetone. 4'-Hydroxymethyl was installed by [3,3]-sigmatropic rearrangement reaction and 1'-methyl group was introduced by carbonyl addition of methylmagnesium bromide. The coupling of nucleosidic bases and desilylation afforded a series of novel nucleosides. The synthesized compounds $16{\~}19$ were evaluated for their antiviral activity against HIV-1, HSV-1, HSV-2, and EMCV. Compounds 16 and 19 exhibit toxicity non-related to any anti-HIV-1 activity.