The kinetics of the addition of thiourea to cinnamenylisophorone derivatives(X : H, p-Br, p-CH3 m-CH3, p-OCH3) was investigated using ultraviolet spectrophotometry in 20%(v/v) dioxane-H2O at 25℃. A rate equation which can be applied over wide pH range(pH 1.0~13.0) was obtained. In order to investigate the substituent effects of cinnamenylisophorone derivatives. Hammett constant was plotted. As the result, the rate of uncleophilic addition of thiourea to cinnamenylisophorone derivatives was facilitated by electron donating group. It was found that addition of neutral thiourea which was not dissociated at the pH 1.0~9.0 was proceeded, the reaction was proceeded by addition of dissociated anion of thiourea above the pH 10.0. On the basis of this kinetic study, the reaction mechanism of nucleophilic addition of thiourea was investigated.
The kinetics of hydrolysis of cinnamenylisophorone derivatives (rho-H, rho-Br, P-Cl, rho-OCH3) was investigated using ultraviolet spectrophotometry in 20%(v/v) dicxane-H2O at 25℃. A rate equation which can be applied over wide pH range (pH 1.0~13.0) was obtained. In order to investigate the substituent effects on cinnarnenylisophorone derivatives, Hammett constant was plotted. As the result, the rate of hydrolysis of cinnamenylisophorone derivatives was facilitated by electron donating group. Final products of the hydrolysis were benzaldehyde and isophorone, From the measurement of reaction rate constant according to pH changes, substituent effect, and final products, it was found that the hydrolysis of cinnarnenylisophorone derivatives was initiated by the neutral H2O molecule which does not dissociated at below pH 9.0, and in the range of pH 9.0~11.0 this reaction occurs by H2O or hydroxide ion competitively, but proceeded by the hydroxide ion above pH 11.0. On the basis of this kinetic study, the reaction mechanism of the hydrolysis of cinnamenylisophorone derivatives was proposed.
The kinetic of hydrolysis for cinnamylidene aniline derivatives has been investigated by ultraviolet spectrophotometry in 20% (v/v) dioxane - H2O at 25℃. A rate equation which can be applied over wide pH range was obtained. The substituent effects on cinnamylidene aniline derivatives were studied and the hydrolysis was facilitated by electron attracting group. Final products of the hydrolysis were cinnamaldehyde and aniline. From the rate equation, substituent effect and final products, the hydrolysis of cinnamylidene aniline derivatives was initiated by the neutral molecule of H2O which does not dissociate at below pH 9.0~12.0, but proceeded by the hydrogen ion at above pH 5.0~9.0.
The Kinetics of the addition of benzalacetophenone derivatives was investigated by ultraviolet spectrophotometery in 5% dioxane H2O at 50℃. A rate equation was obtained in wide range of pH. The substituent effects on benzalacetophenone derivatives were studied, and addition were facilitated by electron attracting groups. The final product was benzalacetophenone-β-thioglycolic acid synthesized by the addition of thioglycolic acid to benzalacetophenone. On the base of the rate equation, substituent effect, general base effect and final product, the plausible addition mechanism was proposed: Below pH 9.0, only neutral thioglycolic acid molecule was added to the carbon-carbon double bond, and in the range of pH 9.0~11.0, neutral thioglycolic acid molecule and thioglycolic acid anion competitively attacted the double bond. By contrast, above pH 11.0, the reaction was dependent upon only the addition of thioglycolic acid anion.
The rate constants of the hydrolysis of cinnamanilide derivatives were determined UV spectrometry in H2SO4 (5~20N), NaOH(5~11N) at 50~110℃ and rate equation could be applied over a strong acid and strong base were obtained. Final product of the hydrolysis was a cinnamic acid. The σ values obtained from the slope of linear plots of log kabs vs. Hammet tΣ constants were slightly negatives, Substituents on cinnamanilide showed a relatively small effect, with hydrolysis facilitated be electron donating group. Activation energy(Ea)was also calculated for the hydrolysis of the cinnamanilide. From this reaction rate equation, substituent effect and experimental of rate constants, that the hydrolysis of cinnamanillde was Initiated by the netural molecule of H2O which do not dissociate at strong acid, and proceeded by hydroxide ion at strong base.
The present study aimed to investigate the effects of low temperature on the growth, yield, quality, and biologically active compounds of strawberry and obtain basic information for developing a technology for stable growth of strawberry in greenhouses. Growth of strawberry, including leaf number, area, and length, plant height, and dry weight was better at the optimum growth temperature of 20℃ than at a lower temperature of 15°C. At the low temperature of 15°C, the cultivar 'Maehyang' was more tolerant and displayed better growth rate than 'Seolhyang'. At 15°C, the fruit production per week and fruit weight was lower than that at 20°C. In contrast, fruit length and diameter were not significantly different between the two growth temperatures. Growth temperature also did not affect the fruit color index, Hunter L, a, b value, or fruit firmness. However, the sugar content of strawberries grown at 15 was higher by 0.8 and 1.5 Brix for 'Seolhyang' and 'Maehyang', respectively, than of those grown at 20°C. There was no difference in the content of fisetin, a biologically active compound, for 'Seolhyang' at both growth temperatures, however, the fisetin content of 'Maehyang' was higher at 20°C than at 15 . Cinchonine and ellagic acid content of 'Seolhyang' was higher at 20°C than at 15 , whereas that of 'Maehyang' was higher at 15°C than at 20℃ . Quercetin content showed no significant differences with respect to growth temperature, however, it tended to increase at 20°C. The cinnamic acid content of 'Seolhyang' was higher at 15°C than at 20℃ , whereas that of 'Maehyang' increased at 20°C. Collectively, the biologically active compounds of strawberry were affected by growth temperature. Moreover, the content of these compounds tended to increase at 20°C, the optimum growth temperature, rather than at the sub-optimal growth temperature of 15°C.