• Journal of the Korean Chemical Society
• /
• v.49 no.6
• /
• pp.617-622
• /
• 2005

• Journal of the Korean Chemical Society
• /
• v.57 no.6
• /
• pp.855-858
• /
• 2013

• Bulletin of the Korean Chemical Society
• /
• v.15 no.2
• /
• pp.154-161
• /
• 1994

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.

• Bulletin of the Korean Chemical Society
• /
• v.13 no.2
• /
• pp.166-172
• /
• 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.

• YAKHAK HOEJI
• /
• v.40 no.4
• /
• pp.382-386
• /
• 1996

The compound of the 6,7-dichloroquinoline-5,8-dione has two asymmetric chloro radicals at the position of the C6 and C7. When the compound reacts with ethyl acetoacetate in the presence of sodium ethoxide, it is considered that C6 and/or C7 position of the compound can be substitued. The exact substitued position of the product (I) could not be identified by the NMR analysis in our experiment. Therefore, we synthesized the 3-ethoxycarbonyl-2-methyl-1-N-propyl pyridino(2,3f)indole-4,9-dione by reaction of the product (I) with propylamine via intramolecular cyclization to identify the substitued position of the product (I) using the X-ray crystallographic structure analysis. The result demonstrates that the position of nucleophilic substitution of the product (I) is at the position of the C6.

• Journal of the Korean Chemical Society
• /
• v.44 no.3
• /
• pp.229-236
• /
• 2000

The reaction of 6-chloro-2-hydrazinoquinoxaline 4.oxide(10) with acetylacetone or dibenzoylmethane gave 6-chloro-2-(3,5-disubstituted pyrazol-1-yl)quinoxaline 4-oxides (11) through the intramolecular·cyclization.The chlorination of compound 11 with phosphoryl chloride afforded 3,6-dichloro-2-(3,5-disubstituted pyrazol-1-yl)quinoxalines (12), whose reaction with hydrazine hydrate provided 6-chloro-3-hydrazinodehydes, benzenesulfonyl chloride, substituted benzoyl chlohdes or acyl chlorides gave novel pyrazolylquinoxalines (14-17).

• Bulletin of the Korean Chemical Society
• /
• v.26 no.2
• /
• pp.273-277
• /
• 2005

Dynamic resolution of $\alpha$-bromo tertiary acetamides in asymmetric nucleophilic substitution reaction is described. Intermolecular substitution of $\alpha$-bromo tertiary acetamides with dibenzylamine in the presence of TBAI and $Et_3N$ gave the dipeptide analogues 7-10 with high stereoselectivities up to 90 : 10 dr. Also, cyclic dipeptide analogues 20-29 were produced by the intramolecular nucleophilic cyclization of $\alpha$-bromo tertiary acetamides with low stereoselectivities in 84-42% yields.

• YAKHAK HOEJI
• /
• v.41 no.5
• /
• pp.582-587
• /
• 1997

The 6.7-dichloroquinoline-5,8-dione (I) was reacted with ethyl acetoacetate in the presence of sodium ethoxide to yield 6-(${\alpha}$-acetyl-${\alpha}$-ethoxycarbonyl methyl)-7-chloro-qui noline-5,8-dione(II). When this compound II was reacted with some arylamine (phenyl, p-toluyl, p-fluorophenyl, p-chlorophenyl. p-bromophenyl, p-iodophenyl, p-trifluoromethylphenyl, p-dimethylaminophenyl,indanyl), 1N-aryl-2-methyl-3-ethoxycarbonyl pyridino[2,3-f]-indole-4.9-dione(IIIa-I) were obtained via intramolecular cyclization.

• YAKHAK HOEJI
• /
• v.40 no.1
• /
• pp.19-24
• /
• 1996

The 6,7-dichloroquinolone-5,8-dione(I) was reacted with ethyl acetoacetate in the presence of sodium ethoxide to yield 6-(${\alpha}$-acetyl-${\alpha$-ethoxycarbonyl-methyl)-7-chloro-quin oline-5,8-dione(II). When this compound II was reacted with some alkylamine (methylamine, ethylamine, propylamine, isopropylamine, cyclopropylamine, methoxyethylamine, ethanolamine, benzylamine, furfurylamine), 1N-alkyl-2-methyl-3-ethoxycarbonyl-pyridino(2,3f)-indole-4,9-dione(IIIa-i) were obtained via intramolecular cyclization.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.2
• /
• pp.357-362
• /
• 2008

A method for synthesizing o-carborane substituted tetrahydroisoquinolines containing a polar functional group such as sulfamide, sulfonic, or phosphoric acid on the nitrogen atom of the piperidine ring, starting from arylethylamine, N-(2-arylethyl)sulfamide, N-(2-arylethyl)sulfamic acid or 2-arylethylamidophosphate, is described. In vitro studies showed the desired compounds 10, 15, 19, and 25 synthesized accumulate to high levels in B-16 melanoma cells with low cytotoxicity.