• Bulletin of the Korean Chemical Society
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• 제15권6호
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• pp.460-465
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• 1994

New silicon-monosubstituted (${\eta}^4$-2,3,4,5-tetraphenyl-l-silacyclopentadiene)transi tion metal complexes are described. (7-Alkyl-7-silanorbornadienyl)MLn(Alkyl=Methyl: MLn=CpRu$(CO)_2$: Alkyl=Methyl: MLn=CpNi(CO): Alkyl=Ethyl: MLn=CpNi(CO)) complexes were prepared from the corresponding silole-transition metal complexes with dimethylacetylenedicarboxylate. Cycloaddition products were obtained with 2,3-dimethyl-1,3-butadiene, 2,3-butanedione, and 1,4-benzoquinone through the ruthenium-substituted silylene. We have determined the crystal structure of (1-methyl-2,3,4,5-tetraphenyl-l-silacyclopentadien yl)cyclopentadienyldicarbonylruthenium by using graphite monochromated Mo-Ka radiation. The compound was crystallized in the monoclinic space group $P2_{1/c}$ with a = 9.838(l), b = 15.972(3), c = 18.327(3) ${\AA}$, and ${\beta}= 94.28(l)^{circ}$. The ruthenium moiety CpRu$(CO)_2$ on silicon is in an axial position.

• 고무기술
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• 제13권1호
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• pp.1-9
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• 2012

Click chemistry had enjoyed a wealthy decade after it was introduced by K.B.Sharpless and his co-worker on 2001. Since there is no optimized method for synthesis of click polymer, therefore, this paper introduced three click reaction methods such as catalyst, non-catalyst and azide-end capping for fluorene-based functional click polymers. The obtained polymers have reasonable molecular weight with narrow PDI. The polymers are thermally stable and almost emitted blue light emission. The synthesized fluorene-based functional click polymers were characterized to compare the effect of click reaction methods on polymer electro-optical properties as well as device performance on quasi-solid-state dye sensitized solar cells (DSSCs) applications. The DSSCs with configuration of $SnO_2:F/TiO_2/N719$ dye/quasi-solid-state electrolyte/Pt devices were fabricated using these click polymers as a solid-state electrolyte components. Among the devices, the catalyzed click polymer composed device exhibited a high power conversion efficiency of 4.62% under AM 1.5G illumination ($100mW/cm^2$).These click polymers are promising materials in device application and $Cu^I$-catalyst 1, 3-dipolar cycloaddition click reaction is an efficient synthetic methodology.

• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.2021-2026
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• 2005

The oxidation of cytidine 1 and inosine 5 by sodium metaperiodate followed by the reaction of the product with $CH_3I$ in NaOH afforded 2',4'-dihydroxyhexopyranosyl derivatives 2 and 14 respectively. The reaction of thiophene-2-carboxylic acid or furfural with cytidine were taken place via cycloaddition afforded adducts 3 and 4 respectivily. The bromination of inosine 5 or its 2',3'-O-isopropylidine inosine 6 led to the formation of 8-bromoanalogue 7 and 8, respectively. The reaction of 8-bromo-2',3'-O-isopropylidine inosine (8) with ethylglycinate hydrochloride afforded 8-ethoxycarbonylmethylaminoinosine 9. The alkylation of the compound 6 with urea led to the formation of 3-carbonylaminoinosine 10. The oxidation of 6 with DCC afforded 4'-formyl derivative 11, which on reaction with ethyl glycinate hydrochloride followed by reaction with sodium cyanoborohydride afforded 12, while the treatment of dialdehyde inosine 13 with ethyl cyanoacetate in the presence of 0.5 N NaOH afforded compound 15.

• Bulletin of the Korean Chemical Society
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• 제30권1호
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• pp.157-162
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• 2009

General, fast, and efficient methods for the synthesis of Fréchet-type dendrimers having core diversities were elaborated. Two core building blocks, 4,4'-(3,5-bis(propargyloxy)benzyloxy)bisphenyl and N,N,N',N'-tetra(prop-2- ynyloxycarbonylethyl)-1,2-diaminoethane, were designed to serve as the alkyne functionalities for dendrimer growth via click reactions with the azide-dendrons. The synthetic strategy involved an 1,3-dipolar cycloaddition reaction between an alkyne and an azide- functionalized Fréchet-type dendrons in the presence of Cu(I) species which is known as the best example of click chemistry.

• Bulletin of the Korean Chemical Society
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• 제14권4호
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• pp.487-490
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• 1993

A semiempirical methods (PM3-CI-UHF. etc.) for the evaluation of ground and excited state electronic structures of psoralens are applied to angelicin with thymine. The photocycloaddition reaction of angelicin with thymine were deduced to be formed by their preferable HSOMO-LUMO interactions. The photoadduct was inferred to be a C$_{4-}$cycloaddition product with the stereochemistry of cis-anti formed through [2+2] addition reaction between, the 3,4 double bonds of angelicin and the 5,6-double bond of thymine.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.229-238
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• 2011

A series of novel glucose derived benzyl and alkyl 1,2,3-triazoles and their hydrochlorides have been synthesized via Cu(I)-catalyzed 1,3-dipolar cycloaddition. All the new compounds were characterized by MS, IR and NMR spectra. The DEPT, APT, $^1H$-$^1H$ and $^1H-^{13}C$ 2D NMR spectra for some compounds were also recorded. These compounds were evaluated for their in vitro antibacterial activities against Staphylococcus aureus ATCC 29213, Bacillus subtilis, Bacillus proteus, Pseudomonas aeruginosa, Escherichia coli ATCC 25922, and antifungal activities against Candida albicans and Aspergillus fumigatus. The bioactive data revealed that (3R,4S,5S,6S)-2-(hydroxymethyl)-6-methoxy-4,5-bis((1-octyl-1H-1,2,3-triazol-4-yl)methoxy)-tetrahydro-2H-pyran-3-ol 8a exhibited excellent antifungal activity against A. fumigatus with an MIC value of 0.055 mM compared to Fluconazole. It also showed broad inhibitory efficacy against tested bacterial strains with MIC values ranging from 0.049 mM to 0.39 mM.

• 한국자기공명학회논문지
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• 제8권1호
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• pp.62-69
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• 2004

Bicyclolactones obtained from the Diels-Alder cycloaddition of 3,5-dibromo-2-pyrone can undergo various palladium catalyzed cross coupling reactions to afford aryl bicyclolactones. The resulting coupled products can be readily converted into various 3-OH cyclohexenes via lactone ring openings, while those bearing dienyl units underwent highly diastereoselective Diels-Alder cycloadditions with selected dienophiles to funish multiply functionalized polycarbocycles. Bromo-bicyclic diene furnished two different diastereomers endo-form (62%) and exo-form (38%) upon cycloadditions with N-Et maleimide (NEM), and their stereochemistries were identified with NMR.

• 대한화학회지
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• 제34권5호
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• pp.469-475
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• 1990

2,6-dichloroquinoxaline (13)과 m-chloroperbenzoic acid를 반응시켜 2,6-dichloroquinoxaline 4-oxide (14)를 합성하고, 이것과 pyrrolidine 혹은 indoline을 반응시켜 2-substituted 6-chloroquinoxaline 4-oxide류(15)를 합성하였다. 그리고 이들과 dimethyl acetylenedicarboxylate를 반응시키니 isoxazolo[2,3-a]quinoxaline류(16)와 pyrrolo[1,2-a]quinoxaline류 (17)가 선택적으로 합성되었다. 더욱이 pyrrolo[1,2-a]quinoxaline류 (17)는 isoxazolo[2,3-a]quinoxaline류 (16)의 고리변환에 의하여 생성된다는 것을 알았다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권1호
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• pp.61-64
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• 2000

A series of 5-oxaproline peptide derivatives was synthesized and evaluated for its ability to inhibit the prolyl 4-hydroxylase in vitro. Structure-activity studies show that the 5-oxaproline sequences, prepared by the 1,3-dipolar cycloaddition of the C-methoxycarbonyl-N-mannosyl nitrone in the presence of the ethylene, are more active than the corresponding proline derivatives. Prolyl 4-hydroxylase belongs to a family of $Fe^{2+}-dependent$ dioxygenase, which catalyzes the formation of 4-hydroxyproline in collagens by the hydroxylation of proline residues in -Gly-Xaa-Pro-Gly- of procollagen chains. In this paper we discover the more selective N-Cbz-Gly-Phe-Pro-Gly-OEt $(K_m\;=\;520\;{\mu}M)$ sequences which are showed stronger binding than others in vitro. Therefore, we set out to investigate constrained tetrapeptide that was designed to mimic the proline structure of pep tides for the development of prolyl 4-hydroxylase inhibitor. From this result, we found that the most potent inhibitor is N-Dansyl-Gly-Phe-5-oxaPro-Gly-OEt $(K_i\;=\;1.6\;{\mu}M)$. This has prompted attempts to develop drugs which inhibit collagen synthesis. Prolyl 4-hydroxylase would seem a particularly suitable target for antifibrotic therapy.

• 대한화학회지
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• 제27권5호
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• pp.368-375
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• 1983

5-아릴-1,3,4-옥시티아졸-2-온을 트리에틸포스파이트와 반응시키면 탈황반응에 의해 벤조니트릴과 에틸포스포로티오에이트가 66~94% 수득율로 얻어졌다. 다른 3가의 인화합물 즉, 트리메틸포스파이트, 트리에틸포스핀, 그리고 트리페닐포스핀들과도 같은 탈황반응이 관찰되었다. 그러나 트리페닐포스파이트와는 전혀 반응하지 않았다. 5-아릴-1,3,4-디티아졸-2-온을 트리페닐포스핀과 반응시키면 티오아실 이소시아네이트가 얻어졌다. 이것은 에테르에서 자체적으로 분해되어 벤조니트릴로 변하게 되나 클로로포름에서는 안정하다. 이 두 반응에서 관찰되는 탈황반응은 인이 고리속으로 들어가 고리를 늘인후 분자내에서의 자리옮김 반응에 의해 일어나는 것이라 생각된다. 클로로포름에서 안정한 티오아실 이소시아네이트는 이민과 1,4-고리화 첨가반응을 일으켜 티아다이아지논을 생성하였다.