• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1931-1935
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• 2011

The synthesis of carbocyclic analogues of normal nucleosides has grown exclusively since they have shown potential antiviral and antitumor activities. Radiolabeled cis-1-[4-(hydroxy-methyl)-cyclopent-2-enyl]-5-$[^{124}I]$-iodocytosine (carbocyclic d4IC) and cis-1-[4-(hydroxy-methyl)-cyclopent-2-enyl]-5-(2-$[^{124}I]$iodovinyl)cytosine(carbocyclic d4IVC) were synthesized. The synthetic route employed Pd(0)-catalyzed coupling reaction together with organotin and exchange reaction for radioiodination as key reactions. Carbocyclic $[^{124}I]$d4IC gave more than 75% radiochemical yield with greater than 95% radiochemical purity. Carbocyclic $[^{124}I]$d4IVC gave more than 80% radiochemical yield with greater than 95% radiochemical purity.

• Bulletin of the Korean Chemical Society
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• 제32권9호
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• pp.3382-3388
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• 2011

Reaction of barbituric acid (BA), 1,3-dimethyl barbituric acid (DMBA) and 2-thiobarbituric acid (TBA) with cyanogen bromide and aldehydes in the presence of L-(+)-tartaric acid afforded a new route for the synthesis of stable heterocyclic 5-aryl-1H,1'H-spiro[furo[2,3-d]pyrimidine-6,5'-pyrimidine]2,2',4,4',6'(3H,3'H,5H)-pentaones which is a dimeric form of barbiturate (uracil and thiouracil derivative). In the reaction of 1,3-diethyl thiobarbituric acid (DETBA) the Knoevenagel condensation and then Michael adducts were obtained under the same condition. Structure elucidation is carried out by $^1H$ NMR, $^{13}C$ NMR, FT-IR and Mass analyses. Mechanism of the formation is discussed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.227-227
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• 2010

The intercalation chemistry of graphite presents an attractive route to obtain few-layered graphene platelets based on the expanded interlayer spacing. We report that the lithium can be intercalated into the graphite in a controllable manner by adjusting the variables such as temperature, pressure, and reaction time. From the X-ray diffraction experiments, the lithium-graphite intercalaltion compounds (Li-GICs) can be produced as the first stage compounds ($LiC_6$), the second-stage compounds ($LiC_{12}$), and the mixtures, which is most likely to be dependent on the temperature and reaction time. Since these Li-GICs are expected to facilitate the exfoliation of graphite, we investigated the feasibility of Li-GICs as a effective precursors for the generation of single-or few-layered graphite nano-platelets.

• 대한기계학회논문집A
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• 제29권3호
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• pp.425-431
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• 2005

The efficiency of complex slurry preparation route for developing the high performance SiC matrix of $RS-SiC_{f}/SiC$ composites has been investigated. The green bodies for RS-SiC materials prior to the infiltration of molten silicon were prepared with various C/SiC complex slurries, which associated with both the sizes of starting SiC particles and the blending conditions of starting SiC and C particles. The characterization of Rs-SiC materials was examined by means of SEM, EDS and three point bending test. Based on the mechanical property-microstructure correlation, the process optimization is also discussed. The flexural strength of Rs-SiC materials greatly depended on the content of residual Si. The decrease of starting SiC particle size in the C/SiC complex slurry was effective for improving the flexural strength of RS-SiC materials.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2514-2518
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• 2010

A very simple synthetic route of a novel SATE prodrug type of 6'-fluoro-6'-methyl-5'-noradeonosine carbocyclic nucleoside phosphonic acid is described. The key fluorinated alcohol intermediate 7 was prepared from the epoxide intermediate 6a via selective ring-opening of epoxide. Coupling of 7 with $N^6$-bis-Boc-adenine under a Mitsunobu reaction followed by phosphonation and deprotection afforded the carbocyclic phosphonic acid. The chemical stability of the bis(SATE) derivative 13 was measured at neutral (pH 7.2) and slightly acidic (Milli-Q water, pH 5.5) pH. The antiviral activity test of the SATE prodrug 13 and its parent nucleoside phosphonic acid 11 were evaluated against HIV-1.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4007-4014
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• 2012

Efficient synthetic route to novel 4'-fluorinated 5'-deoxythreosyl phosphonic acid nucleosides was described from glyceraldehyde using Horner-Emmons reaction in the presence of triethyl ${\alpha}$-fluorophosphonoacetate. Glycosylation reaction of nucleosidic bases with glycosly donor 14 gave the nucleosides which were further phosphonated and hydrolyzed to reach desired nucleoside analogues. Synthesized nucleoside analogues 18, 21, 25 and 28 were tested for anti-HIV activity as well as cytotoxicity. Adenine derivatives 18 and 21 showed significant anti-HIV activity up to $100{\mu}M$.

• 대한화학회지
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• 제28권6호
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• pp.412-417
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• 1984

2-Mercaptobenzothiazole과 알코올로부터 여러가지 알킬유도체를 얻을 수 있었다. 이 방법은 알려진 다른 방법보다 간편하고 수율도 좋고 또 일반성이 있는 장점이 있다. 이렇게 해서 얻은 2-mercaptobenzothiazole에 염소화 반응을 시도한 결과 2-chloromethylthiobenzothiazole을 얻을 수 있었다.

• Archives of Pharmacal Research
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• 제28권7호
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• pp.745-749
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• 2005

A simple synthetic route for the synthesis of novel methyl branched cyclopropyl phosphonic acid nucleosides is described. The characteristic cyclopropyl moiety 8 was constructed by employing Simmons-Smith reaction as a key step. The condensation of mesylate 11 with natural nucleosidic bases (A,C,T,U) under standard nucleophilic substitution conditions ($K_2CO_3$, 18-Crown-6, DMF) and after subsequent hydrolysis resulted in the formation of target nucleosides, 16, 17, 18, and 19. In addition, the antiviral evaluations of the synthesized nucleotides against various viruses were also performed.

• Bulletin of the Korean Chemical Society
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• 제16권11호
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• pp.1037-1042
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• 1995

The reaction of acetophenone 1-ureidoethylidenehydrazones 6 with a mixture of triphenylphosphine, carbon tetrachloride, and triethylamine in dichloromethane provides a general route to 1-(1-phenylethenyl)-5-(N-substituted amino)-1,2,4-triazoles 11 via the electrocyclization of the expected azino carbodiimide intermediates 9 to give the resonance stabilized azomethine imine 10a followed by a proton abstraction from the methyl group by amide anion. However, the same reaction of benzaldehyde 1-ureidoethylidenehydrazones 5 was unsuccessful. Under the same conditions, the reactions of benzaldehyde 1-N-acylureidoethylidenehydrazones 7 or acetophenone 1-N-acylureidoethylidenehydrazones 8 afforded 4H-1,2,4-triazolo[1,5-c][1,3,5]oxadiazines 16 or 17 via the zwitterionic species 15, or a [4+2] intramolecular cycloaddition from the carbodiimide intermediates 14, respectively.

• 통합자연과학논문집
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• 제2권4호
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• pp.289-292
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• 2009

Perchlorosilanes are useful precursors for the synthesis of hydrosilanes for the fabrication of electronic devices such as silicon thin-film transistors and silicon nanoparticles. For this solution process, requirements of precursors applicable to solution process are relatively low volatile and soluble in common organic solvents. In this work, the decaphenylcyclopentasilane has been obtained from the reaction of the lithium wire and dichlorodiphenylsilane. The reaction of decaphenylcyclopentasilane with lewis acid catalyst, HCl/$AlCl_3$, gives the perchlorocyclopentasilane. Decaphenylcyclopentasilane exhibits an unusual optical property. Its optical property was characterized by UV-vis and fluorescence spectroscopy. Absorption wavelength maxima for the decaphenylcyclopentasilane was 272 nm. Decaphenylcyclopentasilane displayed an emission band at 741 nm with excitation wavelength of 272 nm.