• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.350.2-350.2
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• 2002

The reaction of N-acyliminium ion with a variety of nucleophiles is one of the powerful method to introduce various substituents at the a-carbon of an amine. Particularly this type of inter and intramolecular C-C bond formation can be effectively applied to the synthesis of the bioactive natural or unnatural compounds as well as many bioactive peptidomimetics. Accordingly. much attention has been devoted to the practical and efficient methods for the generation of acyliminium ion precursors though there are many important aspects in the reaction involving N-acyliminium ions. (omitted)

• 대한화학회지
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• 제37권2호
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• pp.244-248
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• 1993

니트로 알코올은 브로모 알코올의 치환반응으로 얻었다. 두번째 니트로 원자단은 사슬 길이에 따라 다른 방법으로 도입했다. 3,3-dinitro-1-propanol은 분자내 염기성 니트로화 반응으로 형성되면 5,5-dinitro-1-pentanol은 산화촉매 니트로화 반응으로 얻었다. 3,3-dinitro-1,6-hexanediol과 4,4-dinitro-1,8-octanediol은 3,3-dinitro-1-propanol과 5,5-dinitro-1-pentanol에 acrolein을 가해 Michael 반응으로 알데히드를 얻고 환원하여 합성했다. 치환반응시 알코올 보호기는 아세틸기가 좋으며 산화촉매 니트로 반응에서는 THP 원자단이 좋은 보호기이다.

• Bulletin of the Korean Chemical Society
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• 제29권10호
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• pp.1977-1982
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• 2008

Novel bicyclo[3.1.0]hexanyl purine nucleoside analogues were synthesized as potential antiherpetic agents via a bicyclo[3.1.0]hexanol (${\pm}$)-8, which was prepared using a highly efficient carbenoid cycloaddition reaction. A highly diastereoselective reduction of ketone and a Mitsunobu reaction for the condensation of glycosyl donor (${\pm}$)-12 with 6-chloropurine were employed.

• Archives of Pharmacal Research
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• 제20권2호
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• pp.184-190
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• 1997

A new method based on the chemical reaction has been devised for the sequential analysis of reducing oligosaccharides using 8-amino-2-naphthalenesulfonic acid (ANS), a fluorescent precolumn derivatization reagent for reducing saccharides. The procedure established includes 1) the derivatization of a reducing oligosaccharide to produce a Schiff base, 2) the reduction of the base with sodium cyanoborohydride $(NaBH_3/CN), 3)$ the methoxycarbonylation of the resultant secondary amino group, 4) the cleavage of the glycoside bond next to the reducing end, based on the intramolecular acid hydrolysis by the action of a sulfonic acid group of the ANS derivative, 5) the identification of the liberated reducing end by high-performance liquid chromatography (HPLC), and finally 6) the recovery of the resultant oligosaccharide fragment from the cleavage reaction mixture. The extensive examination of the conditions for the sequential analysis of reducing oligosaccharides resulted in the procedure of simplicity , high selectivity and high recovery. This procedure was found to be useful for the sequential analysis of di-, tri- and tetrasaccharides.

• Bulletin of the Korean Chemical Society
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• 제28권1호
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• pp.17-28
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• 2007

Indium and gallium have emerged as useful metals in organic synthesis as a result of its intriguing chemical properties of reactivity, selectivity, and low toxicity. Although indium belongs to a main metal in group 13, its first ionization potential energy is very low and stable in H2O and O2. Therefore, indium-mediated organic reactions are of our current interest. On the basis of these properties of indium, many efficient indium-mediated organic reactions have been recently developed, such as the addition reactions of allylindium to carbonyl and iminium groups, the indium-mediated synthesis of 2-(2-hydroxyethyl)homoallenylsilanes, the indiummediated allylation of keto esters with allyl halides, sonochemical Reformatsky reaction using indium, the indium-mediated selective introduction of allenyl and propargyl groups at C-4 position of 2-azetidinones, the indium-mediated Michael addition and Hosomi-Sakurai reactions, the indium-mediated β-allylation, β- propargylation and β-allenylation onto α,β-unsaturated ketones, the highly efficient 1,4-addition of 1,3-diesters to conjugated enones by indium and TMSCl, and the intramolecular carboindation reactions. Also, we found gallium-mediated organic reactions such as addition reactions of propargylgallium to carbonyl group and regioselective allylgallation of terminal alkynes.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.2081-2085
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• 2014

Second-order rate constants ($k_N$) have been measured spectrophotometrically for the reactions of phenyl 2- pyridyl carbonate (6) with a series of cyclic secondary amines in MeCN at $25.0{\pm}0.1^{\circ}C$. The Br${\o}$nsted-type plot for the reaction of 6 is linear with ${\beta}_{nuc}$ = 0.54, which is typical for reactions reported previously to proceed through a concerted mechanism. Substrate 6 is over $10^3$ times more reactive than 2-pyridyl benzoate (5), although the reactions of 6 and 5 proceed through the same mechanism. A combination of steric hindrance, inductive effect and resonance contribution is responsible for the kinetic results. The reactions of 6 and 5 proceed through a cyclic transition state (TS) in which H-bonding interactions increase the nucleofugality of the leaving group (i.e., 2-pyridiniumoxide). The enhanced nucleofugality forces the reactions of 6 and 5 to proceed through a concerted mechanism. In contrast, the corresponding reaction of 4-nitrophenyl 2-pyridyl carbonate (7) proceeds through a stepwise mechanism with quantitative liberation of 4-nitrophenoxide ion as the leaving group, indicating that replacement of the 4-nitrophenoxy group in 7 by the PhO group in 6 changes the reaction mechanism (i.e., from a stepwise mechanism to a concerted pathway) as well as the leaving group (i.e., from 4-nitrophenoxide to 2-pyridiniumoxide). The strong electron-withdrawing ability of the 4-nitrophenoxy group in 7 inhibits formation of a H-bonded cyclic TS. The presence or absence of a H-bonded cyclic TS governs the reaction mechanism (i.e., a concerted or stepwise mechanism) as well as the leaving group (i.e., 2-pyridiniumoxide or 4-nitrophenoxide).

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2448-2452
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• 2014

Second-order rate constants ($k_N$) have been measured spectrophotometrically for $S_NAr$ reactions of Y-substituted-phenoxy-2,4-dinitrobenzenes (1a-1g) with hydrazine and glycylglycine in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. Hydrazine is 14.6-23.4 times more reactive than glycylglycine. The magnitude of the ${\alpha}$-effect increases linearly as the substituent Y becomes a stronger electron-withdrawing group (EWG). The Br${\o}$nsted-type plots for the reactions with hydrazine and glycylglycine are linear with ${\beta}_{lg}=-0.21$ and -0.14, respectively, which is typical for reactions reported previously to proceed through a stepwise mechanism with expulsion of the leaving group occurring after rate-determining step (RDS). The Hammett plots correlated with ${\sigma}^{\circ}$ constants result in much better linear correlations than ${\sigma}^-$ constants, indicating that expulsion of the leaving group is not advanced in the transition state (TS). The reaction of 1a-1g with hydrazine has been proposed to proceed through a five-membered cyclic intermediate ($T_{III}$), which is structurally not possible for the reaction with glycylglycine. Stabilization of the intermediate $T_{III}$ through intramolecular H-bonding interaction has been suggested as an origin of the ${\alpha}$-effect exhibited by hydrazine.

• 대한화학회지
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• 제10권1호
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• pp.25-31
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• 1966

폴리아크릴로니트릴을 加熱할 때 着色과 同時에 構造變化가 있다는 것은 잘 알려진 事實이며 이것은 部分水素化나프틸리딘型環을 形成함에 基因하는 것으로 알려지고 있다. 本硏究는 이와 같은 構造變化의 反應을 動力學的 및 統計學的으로 取扱하여 지금까지 알려지지 않았던 새로운 事實들을 發見하였다. 첫째로 폴리아크릴로니트릴을 加熱할 때의 니트릴基의 減少는 一次反應이라는 것이며 이는 環形成反應이 긴連鎖反應으로 이루어지지 않는다는 것을 말해 주는 것이다. 다시 말하면 環形成時의 kinetic chain length는 極히 짧다는 것이다. 또 本 構造變化는 반드시 分子間反應(架橋結合)이 아니드라도, 일어날 수 있다는 것을 證明했다. 둘째로 環形成으로 니트릴基가 減少할 때 19~22%의 니트릴基가 殘存한다는 것이며 이를 統計學的으로 解析해본 結果 19.2%라는 計算値를 얻었으며 이는 實驗値와 잘 맞는 數値이다.

• 대한화학회지
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• 제57권5호
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• pp.612-617
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• 2013

The versatile, hitherto unreported 3-(4-(2-phenyldiazenyl)-2-oxo-2H-chromen-3-yl)-3-oxopropanenitrile 3 was prepared by two convenient routes: either by the reaction of ethyl 4-(2-phenyldiazenyl)-2-oxo-2H-chromen-3-carboxylate 2 with acetonitrile in the presence of sodium hydride or by treatment of 4-(2-phenyldiazenyl)-3-(2-bromoacetyl)-2H-chromen-2- one 5 with potassium cyanide. Reaction of 3 with heterocyclic diazonium salts 6, 7, 14 and 17 furnished the corresponding hydrazones 8, 9, 15 and 18. The latter hydrazones underwent intramolecular cyclization into the corresponding pyrazolo[5,1- c]-1,2,4-triazine 10, 1,2,4-triazolo[5,1-c]-1,2,4-triazine 11, 1,2,4-triazino[4,3-b]indazole 16 and imidazo[2,1-c]-1,2,4-triazine 19 derivatives, respectively upon refluxing in pyridine.

• 대한화학회지
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• 제42권4호
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• pp.449-453
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• 1998

6-Chloro-2-hydrazinoquinoxaline 4-oxide(11)와 ethyl chloroglyoxylate를 반응시켜 분자내 고리화반응에 의한 ethyl 8-chloro-4H-1,3,4-oxadiazino[5,6-b]quinoxaline-2-carboxylate(12)를 합성하였다. 화합물 12를 hydrazine hydrate와 반응시켜 $C_2$-hydrazinocarbonyl 유도체 13이 합성되었는데, 이것을 치환 벤즈알데히드류 및 헤테로아릴 알데히드류와 반응시켜 8-chloro-2-(substituted benzylidenehydrazinocarbonyl)-4H-1,3,4-oxadiazino[5,6-b]quinoxaline류(14) 및 8-chloro-2-[(2-substituted methylidene)hydrazinocarbonyl]-4H-1,3,4-oxadiazino[5,6-b]quinoxaline류(15)를 각각 합성하였다.