• Bulletin of the Korean Chemical Society
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• 제31권3호
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• pp.735-738
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• 2010

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.249-252
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• 2004

Cytochrome P450 (P450)/$O_2$/NADPH engender electron transfer reaction of N-benzyl-N-substituted benzylamines to yield corresponding radical cation 1 that is simultaneously converted into 2 and 3. Subsequently, expulsion of proton and hydroxylation yielding a-hydroxylamines are followed by formation of benzaldehydes and benzylamines.

• Bulletin of the Korean Chemical Society
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• 제13권3호
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• pp.252-255
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• 1992

Preparative methods for and catalytic activities of monoaza-18-crown-6 or monoaza-15-crown-5 in the reaction of 1-bromooctane with aqueous KI or NaI were investigated. Monoazacrown ethers were prepared by debenzylation of N-benzylmonoazacrown ethers, obtained from the reaction of N-benzyldiethanolamine and oligoethylene glycol ditosylate. The phase-transfer catalytic activity of N-benzylmonoazacrown ethers was higher than that of the corresponding monoazacrown ethers.

• 폴리머
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• 제33권2호
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• pp.158-163
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• 2009

본 연구에서는 잘 정의된 덴드리틱 폴리스티렌-블록-선형 폴리(3차 부틸 아크릴레이트) 공중합체를 성공적으로 합성하였다. 음이온 중합법을 통해 합성된 폴리스티렌($M_n$=1000 g/mol)을 외곽부분으로 함유하는 덴드론의 수산기 그룹을 토실화(tosylation), 아지드화(azidation), 환원(reduction) 반응을 통해 아민기로 전환하였다. 한편, 선형 poly(t-butyl acrylate)는 DMF 용매에서 benzyl 2-bromopropanoate/Cu(I)Br, PMDETA/t-butylacrylate를 각각 개시제/촉매 시스템/단량체로 사용하여, 원자이동라디칼 중합법(atom transfer radical polymerization, ATRP)을 통해 합성할 수 있었고, 말단을 카르복시산 그룹으로 전환하기 위해 수소기체 환경하에서 Pd/C 을 사용하여 탈벤질화(debenzylation) 반응을 수행하였다. 마지막으로, 합성된 덴드리틱 및 선형 블록들을 다이메틸아미노피리딘(4-(dimethylamino)pyridine, DMAP)과 다이아이소프로필카보다이이미드(N,N'-diisopropylcarbodiimide, DIPC)를 이용한 아미드 커플링 방법을 통해 최종 덴드리틱-선형의 블록공중합체를 합성하였다. 합성된 블록공중합체를 수소원자핵공명법 및 겔침투크로마토그래피 방법을 통해 조사한 결과, 잘 정의된 분자량 및 낮은 분자량 분포를 확인할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.289-292
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• 2004

A trisaccharide, GlcNAcp- ${\beta}-(1{\to}3)-Galp-{\alpha}-(1{\to}2)$-6-deoxy-altroHepp- ${\alpha}-(1{\to}O$-propyl, as an O-antigenic repeating unit of C. jejuni serotype O:23 and O:36 was synthesized. Coupling of the GlcNPhth-(1${\to}$3)-Gal disaccharide donor with allyl 6-deoxy-altroHep acceptor in the presence of iodonium dicollidine perchlorate (IDCP) promoter afforded the ${\alpha}$-galactosidic trisaccharide with high stereoselectivities. Subsequent deacetalation, dephthaloylation, N-acetylation, and hydrogenolytic debenzylation furnished the title compound.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.174-178
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• 2013

A highly reliable dealkylation protocol of alkyl aryl ethers, whose alkyl groups are longer than methyl group, has been developed. We report that various ethyl, n-propyl, and benzyl aryl ethers are successfully cleaved using an ionic liquid, 1-n-butyl-3-methylimidazolium bromide, [bmim][Br], under microwave irradiation. Despite many characteristics such as lower cost and less toxicity of the alkylating agents, and greater hydrophobicity of the products, longer alkyl ethers have been significantly less exploited than methyl ethers, probably due to more difficulty in the deprotection step. Since it has the same advantages as the demethylation method developed by this group including mild conditions, short reaction time, and small use of the ionic liquids, the dealkylation protocol can greatly encourage the broader use of longer alkyl groups in the protection of phenolic groups. As with our previous study of demethylation using [bmim][Br], the microwave irradiation is crucial for the deprotection of longer alkyl aryl ethers. Unlike the conventional heating, which causes either low conversion or decomposition, the microwave irradiation seems to more effectively provide energy to cleave the ether bonds and therefore suppresses the undesired reactions.

• Macromolecular Research
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• 제12권4호
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• pp.359-366
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• 2004

The polysaccharide, (1\longrightarrow5)-$\alpha$-D-ribofuranan, was synthesized by a cationic ring-opening polymerization of 1,4-anhydro-2,3-di-O-benzyl-$\alpha$-D-ribopyranose with the aid of boron trifluoride etherate and subsequent debenzylation. This polysaccharide catalyzed the hydrolysis of ethyl p-nitrophenyl phosphate, uridylyl(3'\longrightarrow5')uridine ammonium salt, and 4-tert-butylcatechol cyclic phosphate N-methyl pyridinium. The polymer also catalyzed the cleavage of nucleic acids (DNA and RNA). The hydrolysis of ethyl p-nitrophenyl phosphate in the presence of the polymer was accelerated by 1.5 ${\times}$ 10$^3$ times relative to the uncatalyzed reaction. The catalytic activity was attributable to the vic-cis-diols of the riboses being located inside the active center that is formed by polymer chain folding; these diols form hydrogen bonds with two phosphoryl oxygen atoms of the phosphates so as to activate the phosphorus atoms to be attacked by nucleophile ($H_2O$).