• Journal of the Korean Chemical Society
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• v.64 no.4
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• pp.239-242
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• 2020

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3071-3072
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• 2010

• YAKHAK HOEJI
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• v.41 no.1
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• pp.14-17
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• 1997

(${\pm}$)-3-Deoxygericudranin A was designed and synthesized for the development of novel antitumour agent and for the elucidation of the effect of 3-hydroxyl group in gericudranin A on antitumour activity. 2,4.6-Trihydroxyacetophenone was converted to 3-deoxygericudranin A in 5 steps via sequential protection, aldol condensation, Michael tvpe-cyclization, regioselective, C-benzylation and deprotection.

• Bulletin of the Korean Chemical Society
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• v.13 no.2
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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.

• The Korean Journal of Nuclear Medicine
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• v.39 no.4
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• pp.215-223
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• 2005

Current interest in the regioselective N-functionalization of tetraazacycloalkanes (cyclen and cyclam) stems mainly from their complexes with radioactive metals for applications in diagnostic ($^{64}Cu,\;^{111}In,\;^{67}Ga$) and therapeutic ($^{90}Y$) medicine, and with paramagnetic ions for magnetic resonance imaging ($Gd^{+3}$). Selective methods for the N-substitution of cyclen and cyclam is a crucial step in most syntheses of cyclen and cyclam-based radiometal complexes and bifunctional chelating agents. In addition, mixing different pendent groups to give hetero-substituted cyclen derivatives would be advantageous in many applications for fine-tuning the compound's physical properties. So far, numerous approaches for the regioselective N-substitution of tetraazacycloalkanes and more specifically cyclen and cyclam are reported. Unfortunately, none of them are general and every strategy has its own strong points and drawbacks. Herein, we categorize numerous regioselective N-alkylation methods into three strategies, such as 1) direct substitution of the macrocycle, 2) introductiou of the functional groups prior to cyclization, and 3) protection/iunclionallrationideproteclion. Our discussion is also split into the methods of mono- and tri-functionalization and di-functionalizataion based on number of substituents. At the end, we describe new trials for the new macrocycles which iorm more stable metal complexes with various radiometals, and briefly mention the commercially available tetraazacycloalkanes which are used for the biconjugation of biomolecules.

• Bulletin of the Korean Chemical Society
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• v.12 no.1
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• pp.26-31
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• 1991

Facile and efficient syntheses of terpenic perfumeries cis-jasmone, dihydrojasmone, and tetrahydrojasmone have been investigated. Cis-jasmone was synthesized by successive metallation followed by alkylation of acetone N,N-dimethylhydrazone with (Z)-2-penten-1-yl tosylate (or 2-pentyn-1-yl tosylate) and propylene oxide in one flask to give a ketonic alcohol, which was oxidized to the corresponding diketone, followed by base-catalyzed intramolecular aldol condensation to give a regioselective cyclization product. Dihydrojasmone and tetrahydrojasmone could be conveniently obtained from 2-octanone. The dimethylhydrazone of the ketone was lithiated with butyllithium and reacted with propylene oxide to give a ketonic alcohol, which was oxidized to a diketone, followed by base-catalyzed intramolecular cyclization to afford dihydrojasmone. Tetrahydrojasmone was prepared by converting the ketonic alcohol into corresponding iodoketone, followed by base-catalyzed intramolecular cycloalkylation to furnish an odoriferous product.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1387-1390
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• 2011

• Archives of Pharmacal Research
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• v.22 no.4
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• pp.398-400
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• 1999

Sufentanil, a potent anilidopiperidine analgesic, was synthesized from a simple thiophenylethylamine via six sequence. The key parts of this synthesis involved an efficient construction of thiophenylethylpiperidone by aminomethano desilylation-cyclization followed by Swern oxidation and a direct regioselective N-nucleophilic spiral epoxide cleavage with aniline promoted by Lewis acids.

• YAKHAK HOEJI
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• v.43 no.5
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• pp.559-565
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• 1999

The two gericudranin E derivatives, GER-I & II, were synthesized and evaluated their antitumour activities for the elucidation of structure-activity relationship. 2,4,6-Trihydroxyacetophenone was converted to target molecules GER-I and GER-B in 5 steps via sequential protection, aldol condensation, Michael type-cyclization, regioselective C-benzylation. The cellular growth inhibition of compounds GER-I and GER-II were investigated against P388, L1210, K562, HCT-15, SK-HepG-1, MCF-7 as cancer cell lines and mouse splenocytes as a normal cell by MTT assay.

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