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임응찬,한인웅,이승준,박재호,조방현,서형수,정구용,한기원,김진원,임상규,이재윤 三陟大學校 1996 論文集 Vol.29 No.2
By impproving the educational program of the Department of Architectural Engineering and studying the theory of learning and the applied method necessary for the development of nation and society, we should develop a satisfying course of education to meet the demand and skill in the industralized society for the purpose of cultivating men of baility with great personalities and creative minds. Therefore, this study focused on classifying several kinds of occupations in the prart of architectured related to what graduates from the department of Architectural Engineering go with into the society. Accordingly after choosing some works adequate to each occupation by the proposed curricula, we tried to establish the scope of education and courses corresponding to the jobs and thus and develop a satisfying curriculum.
金鎭源,鄭求用,林應贊,林相奎,李在允 三陟大學校 1995 論文集 Vol.28 No.1
To serve the objectives of Architectural Design Course, that is, to develop professional worker our country and society keenly need, this study was carried out as a program to ensure the special domain of vocational educational institution. To carry out such and education, a practical curriculum should be developed and according to it education should be effectively accomplished so that students could find it easy to seek for work on leaving school, and that they could make progress their field.
Exploratory Study of Photocyclization Reactions of N-(Trimethylsilylmethylthioalkyl)phthalimides
Ung Chan Yoon,Sang Jin Lee,Kyung Ja Lee,Sung Ju Cho,Chan Woo Lee,Patrick S. Mariano Korean Chemical Society 1994 Bulletin of the Korean Chemical Society Vol.15 No.2
Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethylthioalkyl)phthalimides (alkyl=ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl). Photocyclizations occur in methanol in modest to high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from sulfur in the ${\alpha}$-silylmethylthioalkyl groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate ${\alpha}$ -silylmethylthio cation radicals and cyclization by radical coupling is proposed. In contrast, photoreactions of N-(trimethylsilylmethylthioalkyl)phthalimides in acetone follow different reaction routes to produce another cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon ${\alpha}$ to silicon and sulfur atoms via triplet carbonyl hydrogen abstraction pathway. The normal singlet SET pathway dominates this triplet process for photoreactions of these substances in methanol while the triplet process dominates the singlet SET pathway for those in acetone. The efficient and regioselective cyclization reactions observed for photolyses in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.
Yoon, Ung-Chan,Kim, Moon-Jung,Moon, Jae-Joon,Oh, Sun-Wha,Kim, Hyun-Jin,Mariano, Patrick S. Korean Chemical Society 2002 Bulletin of the Korean Chemical Society Vol.23 No.9
Photochemical reactions of aromatic carbonyl compounds with silyl ketene acetals have been explored. Irradiation of acetonitrile or benzene solutions containing aryl aldehydes or ketones in the presence of silyl ketene acetals is observed to promo te formation of ${\beta}-hydroxyester$, 2,2-dioxyoxetane and 3,3-dioxyoxetane products. The ratios of these photoproducts, which arise by competitive single electron transfer (SET) and classical Paterno-Buchi mechanistic pathways, is found to be dependent on the degree of methyl-substitution on the vinyl moieties of the ketene acetals in a manner which reflects expected alkyl substituent effects on the oxidation potentials of these electron rich donors. An analysis of the product distribution arising by irradiation of a solution containing butyrophenone (6) and the silyl ketene acetal 9, derived from methyl isobutyrate, provides an estimate of the rate constants for the competitive Norrish type Ⅱ, SET and Paterno-Buchi processes occuring. Finally, sequences involving silyl ketene acetal-aryl aldehyde or ketone photoaddition followed by 2,2-dioxyoxetane hydrolysis represent useful procedures for Claisen-condensation type, ${\beta}-hydroxyester$ synthesis.
Yoon, Ung-Chan,Oh, Sun-Wha,Moon, Seong-Chul,Hyung, Tae-Gyung Korean Society of Photoscience 2002 Journal of Photosciences Vol.9 No.1
Studies have been conducted to explore photoaddition reactions of N-methylthiophthalimide with $\alpha$-silyl-n-electron donors Et$_2$NCH$_2$SiMe$_3$, n-PrSCH$_2$SiMe$_3$ and EtOCH$_2$SiMe$_3$. Photoaddition of $\alpha$-silyl amine Et$_2$NCH$_2$SiMe$_3$ to N-methylthiophthalimide occurs in $CH_3$CN and benzene to produce non-silicon containing adduct in which thiophthalimide thione carbon is bonded to $\alpha$-carbon of $\alpha$-silyl amine in place of the trimethylsilyl group. In contrast, photoaddition of EtOCH$_2$SiMe$_3$ to N-methylthiophthalimide generates two diastereomeric adducts in which thiophthalimide thione carbon is connected to $\alpha$-carbon of $\alpha$-silyl ether in place of u-hydrogen. Based on a consideration of the oxidation potentials of u-silyl-n-electron donors and the nature of photoadducts, mechanism for these photoadditions involving single electron transfer(SET) -desilylation and H atom abstraction pathways are proposed.
Dipole-Forming Photochemical Group Transfer Reactions of Phthalimides and ${\alpha}-Ketoamides$
Yoon, Ung-Chan,Mariano Patrick S. Korean Society of Photoscience 2005 Journal of Photosciences Vol.12 No.3
Results of studies of SET-promoted dipole-forming photochemical group transfer reactions of phthalimide and ${\alpha}-ketoamide$ derivatives are discussed. Azomethine ylide forming photochemical reactions, which are initiated by intramolecular SET from tethered silylmethyl-, carboxymethyl-, and ${\beta}-hydroxyethyl$ containing electron donors to excited states of phthalimides, related maleimides, and conjugated imides, are presented first. Following this, investigations of regioselective 1,4-dipole forming photochemical reactions of N-trialkylsilylmethyl- and N-trialkylstannyl-${\alpha}$-ketoamides are described.
Ung Chan Yoon,Young Sim Koh,Hyun Jin Kim,Dong Yoon Jung,Dong Uk Kim,Sung Ju Cho,Sang Jin Lee Korean Chemical Society 1994 Bulletin of the Korean Chemical Society Vol.15 No.9
Photochemical reactions of saccharin with tertiary amines were explored. Saccharin was found to undergo an acid-base reaction with N-trimethylsilylmethyl-N,N-diethyl amine to form N-trimethylsilylmethyl-N,N-diethyl ammonium saccharin salt which is in equilibrium with free saccharin and N-trimethylsilylmethyl-N,N-diethyl amine insolution. Photoreaction of N-trimethylsilylmethyl-N,N-diethyl ammonium saccharin in $CH_3OH\;or\;CH_3CN$ results in the generation of desilylmethylated product, N,N-diethyl ammonium saccharin mainly along with benzamide. Photoreaction of N-methylsaccharin with N-trimethylsilylmethyl-N,N-diethyl amine in $CH_3OH$ leads to the production of o-(N-methylcarbamoyl)-N-ethylbenzenesulfonamid e as the major product along with N-methylbenzamide as the minor product. On the other hand, photoreaction of N,N,N-triethyl ammonium saccharin, generated from saccharin and triethylamine, produces N-methylbenzamide as the exclusive product. These photoreactions are quenched by oxygen indicating that triplets of saccharin and N-methylsaccharin are the reactive excited states. Based on the consideration of the redox potentials of saccharin and N-trimethylsilylmethyl-N,N-diethyl amine, and the nature of photoproducts, pathways involving initial triplet state single electron transfer are proposed for photoreactions of the saccharins with the ${\alpha}$-silylamine.
Explortory Study of Photocyclization Reactions of N-(Trimethylsilylmethylthicoalkyl)phthalimides
Yoon, Ung Chan,Lee, Sang Jin,Lee, Kyung Ja,Cho, Sung Ju,Lee, Chan Woo,Mariano, Patrick S. 부산대학교 기초과학연구소 1994 부산대학교 기초과학연구소 연구논문집 Vol.14 No.-
Studies have been conducted to explore single electron transfer(SET) induced photocyclization reactions of N-(trimethylsilymethylthioalky) phthalimides (alkyl=ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl). Photocyclizations occur is methanol in modest to high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from sulfur in the α-silylmethylthioalkyl groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate α-silylmethylthioalkyl cation radicals and cyclization by radical coupling is proposed. In contrast, photoreactions of N-(trimethylsilylmethylthioalkyl) phthalimides in acetone follow different reaction routes to produce another cyclized products in which carbon-carbon bond formation takes place between the phthlimide carbonyl carbon and the carbon α to silicon and sulfur atoms via trilpet carbonyl hydrogen abstraction pathway. The normal singlet SET pathway dominates this triplet process for photoreactions of these substances in methanol while the triplet process dominates the singlet SET pathway for those in acetone, The efficient and regioselective cyclization reactions observed for photolyses in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.
Yoon, Ung-Chan,Lee, Sang-Jin,Oh, Sun-Wha,Cho, Dae-Won Korean Society of Photoscience 2001 Journal of Photosciences Vol.8 No.3
Studies have been conducted to explore single electron transfer (SET) promoted photocyclization reactions of ($\omega$-phthalimidoalkylthio)acetic acids (alkyl=ethyl, n-propyl, n-butyl, n -hexyl and n-nonyl). Photocyclizations occur in methanol in modest yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the carboxylic group. The initially formed cyclized products undergo efficient water eliminations to produce enthiol ethers in secondary ground state reactions.
The investigation of photochemical reaction of phototoxic antimalarial compounds
Yoon, Ung-Chan,Epling, Gary-A. The Pharmaceutical Society of Korea 1980 Archives of Pharmacal Research Vol.3 No.2
The goal of this research is to provide information that will lead to the development of new non-phototoxic antimalarial compounds. The goal was approached by first learning the chemical mechanism of phototoxicity of six representative compounds 1a-f: a[(diethyl-, -dihexyl-, and -dioctyl- aminomethyl)]-2-(3', 4' -dichlorophenyl)-6-methoxy-4-quinolinemethanol (1a, 1b, and 1c) and .alpha. [(diethyl-, -dibutyl-, and -dihexyl-aminomethyl)]-2-(-4'-methoxyphenyl-6-methoxy-7-chloro-4-quinolinemethan ol (1d, 1e, and 1f). The photochemical reaction of these compounds was investigated in 2-propanol. Similar photochemical fragmentation reactions accurred in all compounds.