• Bulletin of the Korean Chemical Society
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• 제19권6호
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• pp.686-689
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• 1998

Irradiation of 1-(o-allyloxyphenyl)-2-pentamethyldisilanylethyne (2) in methanol yields two 1 : 1 photoaddition products (3 and 4) via silacyclopropene intermediate. Photolysis of (2) with acetone in deaerated methylene chloride yields site specific and regioselective 1: 1 adducts (7 and 8) via silacyclopropene and 1-sila-1,2-propadiene intermediate, respectively.

• Bulletin of the Korean Chemical Society
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• 제15권8호
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• pp.687-689
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• 1994

• Bulletin of the Korean Chemical Society
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• 제13권5호
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• pp.551-553
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• 1992

An efficient and very short synthesis of epoxy alcohol 5, a key intermediate for leukotriene synthesis, was described. The key reaction involves the regioselective benzylidene acetal formation from methyl 5,6,7-trihydroxyheptanoate 1.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.166-166
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• 1996

A series of 6-(N-arylamino)-7-alkylthio-5,8-quinolinedione derivatives(SQ1-12) were newly synthesized for the evaluation of antifungal activities. 6-(N-Arylamino)-7-chloro-5,8-quinolinediones (RCKs) were treated with Na$_2$S/(CH$_3$)$_2$SO$_2$ in EtOH In give SQs. RCKs were prepared by regioselective nucleophilic substitution of 6,7-dichloro-5,8-quinolinediones with arylamines. In the presence of CeCl$_3$, the N-arylamino groups were introduced at the 6-position of 5,8-quinolinedione ring by the regioselective substitution. These derivatives 1-12 were tested for antifungal and also antibacterial activities, in vitro, against Candida sp., Aspergillus niger and Trichophyton mentagrophytes. The MIC values were determined by the two-fold dilution method.

• Bulletin of the Korean Chemical Society
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• 제29권1호
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• pp.51-56
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• 2008

The regioselective ring opening of epoxides using elemental iodine and bromine in the presence of methimazole (MMI, a anti-thyroid drug) and its metabolite methimazole-disulfide as new catalysts are studied. MMI easily converted in vitro to MMI-disulfide without any double activation presented in vivo. FT-Raman and UV spectroscopies are used to study the interaction of iodine with these catalysts. The results indicate that both catalysts are efficient in polyiodide formation, but MMI-disulfide can catalyze this reaction in higher yield and regioselectivity. The complex [(MMI-disulfide)I]+.I3- is considered to be formed initially which could be bulkier by addition of excess of iodine in the course of the reaction. These bulky nucleophiles have a fundamental role in the high regioselectivity by attacking the less sterically hindered epoxide carbon. In this study we suggest that MMI is readily converted to MMI-disulfide by interaction with iodine or activated iodine in thyroid gland, and this process is responsible for high anti-thyroid activity of MMI.

• Archives of Pharmacal Research
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• 제17권3호
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• pp.139-144
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• 1994

A series of 6-(N-aylamono)-7-chloro-5, 8-quinolinedione derivatives was newly synthesized for the evaluation of antifugal activities. 5-Amino-8-hydroxy-quinoline (II) was treated with $KCLO_3$ in HCl to give 6,7-dichloro-5,8-quinolinediones (III). 6-(N-Arylamino)-7-chloro5,8-quinolinediones 1-13 were prepared by regioselective nucleophilic substitution of III with arylamines. In the presence of $CeCl_3$, the N-arylamono groups were introduced at the 6-position of 5,8-quinolinedione ring by the regioselective substitution. These derivatives 1-12 were tested for natifungal and also antibacterial activites, in vitro, against Canadida albicans, Aspergillus nier, Tricophyton mentagrophytes, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coil. The MIC values were determined by the two-fold agar/steak dilution method. Newly obtained 6-(N-arylamino)-7-chloro5,8-quinolinedione derivatives showed potent antifungal and antibacterial activities. Among these derivatives, 1,3,5,7,8 and 9 showed more potent antifungal activities than fluconazole and griseofulvin. Also most of derivatives were found to be more active than ampicillin against gram-positive bacteria. 1 and 7 showed the very potent antifungal activities. 1 was the most efective in preventing the growth of Candida albicans, Aspergillus niger, Tricophyton mentagrophytes, Bacillus subtills and Staphylococcus aureus at MIC $1.6\;\mu{g/ml}$.

• Bulletin of the Korean Chemical Society
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• 제13권2호
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• pp.166-172
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• 1992

Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethoxyalkyl)phthalimides(alkyl=E thyl, n-propyl, n-butyl, n-pentyl, and n-octyl). Photocyclizations occur in methanol in 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 oxygen in the $\alpha-silylmethoxy$ groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate $\alpha-silylmethoxy$ cation radicals and cyclization by radical coupling are proposed. In contrast, photoreaction of N-(trimethylsilylmethoxyethyl) phthalimide in acetone follows different reaction routes to produce two cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon $\alpha$ to silicon and oxygen atoms via triplet carbonyl hydrogen abstraction triplet carbonyl silyl group abstraction pathways. The normal singlet SET pathway dominates these triplet processes for photoreaction of this substance in methanol. The efficient and regioselective cyclization reactions observed for photolysis in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.297-298
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• 2003

Chitin is a natural biopolymer that, with its derivative chitosan, has been represented as a biomaterial with considerable potential in wide ranging medical applications. But there are some limitations in using chitosan as attained, for instance, the problem of water solubility$^1$. In order to use chitosan in various applications (e.g. drug carrier), chemical modifications are often necessary$^2$. (omitted)

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2825-2828
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• 2013

• Bulletin of the Korean Chemical Society
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• 제24권8호
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• pp.1193-1196
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• 2003

Palladium-catalyzed heteroannulation of 2-amino-3-iodoquinoline derivatives and 1-trimethylsilyl internal alkynes provided highly regioselective pyrrolo[2,3-b]quinolines with trimethylsilyl group next to the nitrogen atom in the pyrrole ring.