• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.3899-3903
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• 2011

General, fast, and efficient fusion methods for the synthesis of dendrimers with 1,3-diynes at a core were developed. The synthetic strategy was employed the oxidative homo-coupling of terminal alkyne. The oxidative homo-coupling reaction of the alkyne-functionalized Frechet-type dendrons 1-Dm was allowed to provide first through fourth generation dendrimers 2-Gm with 1,3-diynes at core. The fusion of the propargylfunctionalized PAMAM dendrons 3-Dm by homo-coupling of terminal alkyne lead to the formation of symmetric PAMAM dendrimers 4-Gm. Their structure of dendrimers was confirmed by $^1H$ and $^{13}C$ NMR spectroscopy, IR spectroscopy, mass spectrometry, and GPC analysis.

• 대한화학회지
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• 제57권3호
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• pp.361-364
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• 2013

A modified synthetic approach to the synthesis of heterocyclic food mutagens, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PHIP) and 2-amino-1,6-dimethylimidazo[4,5-b]pyridine (DMIP) is reported. This route highlights an optimized palladium catalysed Buchwald cross-coupling of 2-halo-1-methyl-imidazo[4,5-b]pyridine with benzophenoneimine followed by acidic hydrolysis to yield compound 7. Using finely tailored conditions, Suzuki cross-coupling reactions with highly efficient catalytic systems were performed as the final step on 8 to introduce the aryl group and methyl group on the heterocyclic core.

• Bulletin of the Korean Chemical Society
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• 제19권11호
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• pp.1239-1244
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• 1998

Derivatives of ethylthio α-D-mannopyranoside as glycosyl donors are compared in coupling efficiency and stercoselectivity with varying thiophilic promoters from methyl triflate (MeOTf), dimethyl(methylthio)sulfonium triflate (DMTST) to iodonium dicollidine perchlorate (IDCP), solvents and glycosyl acceptors. IDCP was the most efficient promoter in coupling of perbenzylated ethylthio-α-D-mannopyranosides (1 and 2), giving α-Dmannosyl disaccharides preferentially, whereas inactive in coupling of 4,6-O-benzylidene derivatives 3 and 4. MeOTf and DMTST promoted coupling of 4,6-O-benzylidene derivatives 3 and 4, but P-D-mannopyranosyl disaccharides were formed preferentially. Coupling reaction was retarded as solvent polarity decreased.

• 한국미생물·생명공학회지
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• 제32권1호
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• pp.29-36
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• 2004

토양으로부터 CGTase를 생산하는 새로운 호열성 세균을 분리하였으며, 형태 및 생리적 특성과 16S ribosomal DNA의 염기서열을 분석한 결과 Geobacillus thermosacchalytycus 로 동정하였다. 호열성 G. thermosacchalytycus가 분비하는 CGTase를 한외여과, 소수성 Phenyl Sephadex CL-4B 클로마토그래피 , 그리고 gel filtration의 순서로 분리 정제하여 정제도 28.2배, 정제수율 12.2%, 그리고 specific activity가 4952.5 units/mg인 CGTase를 얻을 수 있었다. 정제된 CGTase의 분자량은 69,000 dalton이었고, terminal amino sequence는 Asn-Leu-Asn-Lys-Val-Asn-Phe-Thr-Ser-Asp-Val-Val-Tyr-Gln-Ile이었다. 최적 pH 및 온도는 각각 pH 6와$ 50^{\circ}C$였고, pH 6-8과 $60^{\circ}C$에서 장기간 보존할 수 있는 중성 pH의 내열성 효소임을 알 수 있었다. 내열성 CCTase의 cyclization과 coupling 반응의 특정을 검토한 결과 G. thermosacchalytycus가 생산하는 내열성 효소는 $\alpha$-type CGTase이었고, cyclization 반응보다는 coupling반응에 적합한 당전이성이 높은 효소임을 알 수 있었다. 당전이 반응에서 기질 특이성을 검토한 결과 당공여체로는 가용성 전분 그리고 당수용체로는 배당체인 stevioside에 대해 높은 기질 특이성을 보였다. 당전이 반응은 당수용체와 당공여체가 효소와 무작위로 결합하여 진행되는 random ternary complex mechanism으로 반응이 수행되었다.

• 대한화학회지
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• 제61권5호
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• pp.299-303
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• 2017

• Bulletin of the Korean Chemical Society
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• 제23권8호
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• pp.1045-1046
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• 2002

• Bulletin of the Korean Chemical Society
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• 제19권1호
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• pp.25-27
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• 1998

• Bulletin of the Korean Chemical Society
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• 제21권8호
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• pp.757-758
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• 2000

• Bulletin of the Korean Chemical Society
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• 제20권4호
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• pp.403-404
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• 1999

• Bulletin of the Korean Chemical Society
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• 제20권9호
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• pp.1097-1100
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• 1999