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朱東峻 慶熙大學校 1987 論文集 Vol.16 No.-
The solutions of a UV stabilizer 2-(2H-benzotriazol-2-yl)-4-methylphenol(Tinuvin P)in different solvents are iradiated with 300nm UV light and their UV absorbance changes measured. When an equal amount of UV is irradiated, the absorbance decrease is most pronounced in the most polar solution, This result is in accord with the widely accepted UV stabilizer action mechanism but encounter complex (EC) formation can not be explained. Acetyl, benzoyl, p-toluenesulfonyl esters and methyl, benzyl ethers of Tinuvin P have been prepared. After UV irradiation, all of these Tinuvin P derivatives have been converted back to Tinuvin P. This may be due to the photo-Fries rearrangement. No out-of-cage product formation is observed.
주동준 慶熙大學校 1985 論文集 Vol.14 No.-
Surface wettability is one of the most critical properties that bio-medical polymeric materials should maintain for their bio-compatibility. In most cases, such surface wetting properties have been obtained through the addition of simple polymer additives, which results in the gradual loss of surface wettability due to the slow leaching of the wetting agents from polymer matrix upon prolonged use. In addition to the loss of surface wettability, additive-leaching sometimes cause undesired side effects to the hot tissue. These kinds of problems related with the use of simple wetting additives can circumvented by the use of co-polymerizable wetting monomers. Amino acids posses hydrophilic groups such as amino and hydroxyl groups in their structures. In this study two amino acids have been reacted with acryloyl and methacryloyl chloride to from N-acyl amino acids. Remaining carboxylic groups have been masked by forming the corresponding oxazolone ring Oxazolones are compatible with the hydrophobic monomers such as methacryloyl dimethylsiloxanes at the monomer stage. Following the copolymerization, oxazolone ring is easily hydrolyzed under mild conditions to give the polymeric material a good surface wetting property. Little change in the physical properties of material has been observed by copolymerizing the wetting monomers.
3,5-Disubstituted Isoxazole의 합성 및 그 광분해에 관한 연구
박양기,주동준 慶熙大學校 1988 論文集 Vol.17 No.-
The reaction of 1,3-dicarbonyl compounds with hydroxylamine is the method most widely used for the synthesis of 3,5- substituted isoxazoles, such as 3-methyl-5-phenylisoxazole. In this study, 3,5-dimethylisoxazole is treated with methyl iodide and n-butyl bromide in the presence of sodium amide to yield alkylated product at the 5-position of isoxazole ring. Some other 3,5-drsubstituted isoxazoles have been prepared in good to excellent yield by oxidation of the corresponding αβ-unsaturated ketoximes. Isoxazole is known to undergo photoisomerization to form a different 5-membered ring compound. Thus the 3,5-disubstituted is oxazole has been converted to 2,5-disubstituted oxazole upon UV irradiation. In the course of this rearrangement, an azirine intermediate has peen identified. 2-Methyl-5-phenyloxazole, the photolysis product of 3-methyl 5-phenyl-isoxazole with 254 nm, is converted back to the starting material upon irradiation with 300nm UV.
김병희,주동준 慶熙大學校 1992 論文集 Vol.21 No.-
Two polymerizable UV stabilizers were prepared and their properties studied. Thus, 2-hydroxy-4-(2-methacryloylethoxy)benzophenone (2H-4MEB) was obtained by the reaction of 2,4-dihydroxybenzophenone with 2-methacryloyloxyethyl p-toluenesulfonate which in turn had been synthesized from 2-hydroxyethyl methacrylate in 97% yield. Synthesis of another polymerizable UV stabilizer, 2-(2H-benzotriazol-2yl)-4-methyl-6-vinyl phenol (4M-6VP) was accomplished in three steps from commercially available 2-(2H-benzotriazol-2-yl)-4-methyl phenol. The 2H-4MB was homo- and copolymerized with HEMA and MMA. Homopolymerization of 4M-6VP was unsuccessful, but copolymerization with MMA and styrene went smoothly to obtain UV-stabilized polymers.
Aromatic Disulfide를 이용한 Sulfenimine의 합성
丁國聲,朱東駿 慶熙大學校 1989 論文集 Vol.18 No.-
The method used for the preparation of sulfenimines is condensation of a sulfenamide with aldehydes or ketones, and oxidation of the sulfenamides and reaction of aromatic thiols with N-chloro-p-quinone imine, condensation of aromatic disulfides, metal, ammonia and aldehydes or ketones. Several metal ions such as silver, mercury, zinc, copper, cadmium, tin, and lead were employed as catalysts. Among metal ions, silver was superior to other metal catalysts in preparing sulfenimines resulting in high yield. Using the similar procedure, various sulfenimines from α-keto ester or α-keto acid were synthesized. Comparing the results of this study with the result from aldehydes or ketones revealed that steric factor might play an important role in the synthesis of sulfenimines.