아플라톡신 B₁의 酸化反應에 關한 硏究(第Ⅶ報)

張香東 서울産業大學校 1985 논문집 Vol.22 No.1

아플라톡신 B₁에 過옥시酸인 m-클로로 過옥시벤조酸(mCPB)을 作用시키면 未端푸란고리의 二中結合에 酸素가 結合되어 에폭시 化合物이 生成되거나 或은 共鳴으로 安定化된 카르보늄 中間體를 形成하여 시스 및 트란스-8-(3-클로로벤조일옥시)-9-히드록시-8.9-디히드로마플라톡신 B₁을 生成하기도 한다. 시스-2-(3-클로로벤조일옥시)-3-히드록시-2,3,3a,8a-테트라히드로푸로-[2,3-b]-벤조푸란에스테르는 反應條件에 따라 트란스-3-(3-크로로벤조일옥시)-2-히드록시-2,3,3a,8a-테트라히드로푸로-[2,3-b]-벤조푸란으로 자리옮김反應을 한다. 그리고 에틸알코올을 에폭시化系에 附加시켰을 때에는 競爭親核劑로서 作用하여 시스 및 트란스 히드록시 아세탈을 生成하게 된다. Peroxoacid oxidation of aflatoxin B₁resulst in the addition of m-chloro-peroxybenzoic acid(mCPB)across the terminal furane double bond via an epoxide or a resonance-stabilised Carbonium ion intermediate to give cis-and trans-8-(3-chloro benzoyl oxy)-9-hydroxy-8.9-dihydro aflatoxin B₁. The cis-2-(3-chlorobenzoyl oxy)-3-hydroxy-2,3,3a,8a-tetra hydrofuro-[2,3-b]-benzofurane ester rearranges in the reaction conditions to give trans-3-(3-chlorobenzoyl oxy)-2-hydroxy-2,3,3a,8a-tetrahydrofuro-[2,3-b]-benzofurane. When ethyl alcohol is added to epoxidizing system it acts as a competing nucleophile to give cis-and trans-hydroxy acetals.

발암물질인 아플라톡신 G1 에폭시드의 가메탄올 분해에 관한 연구

장향동,류성렬,진주희 한국공업화학회 2000 응용화학 Vol.4 No.1

The methanolysis of anhydrous methyl alcohol (MeOH) with Aflatoxin G₁ (AFG₁) exo-9, 10-epoxide formed predominantly a trans methoxy alcohol (95% over), but the methanolysis of MeOH under acidic conditions with AFG₁ exo-9, 10-epoxide formed a trans methoxy alcohol (84%) and a cis methoxy alcohol (16%). And, the methanolysis of anhydrous MeOH with AFG₁ endo-9, 10-epoxide formed a trans methoxy alcohol (80%), but the methanolysis of MeOH under acidic conditions with AFG₁ endo-9, 10-epoxide formed a cis methoxy alcohol (20%). The methanolysis studies reveal exclusive trans opening of exo-epoxide and under acid conditions, the endo-epoxide formed mixtures of trans and cis(4 : 1) ratio products.

Aflatoxin B₁의 化學的 脫毒素化에 關한 연구(第Ⅰ報)

長香東 서울産業大學校 논문집 Vol.12 No.1

Aflatoxin B₁was treated with many chemicals, especially bases, acids, oxidizing agents and reducing agents in various concentrations under reflux at atmospheric pressure. Less of fluorescence and change of ?? value on TLC were the principal reaction indicators. Also, aflatoxin B1 was treated with formaldehyde alone and in combination with calcium hydroxide, and the products were evaluated chemically. TLC assays revealed that addition of calcium hydroxide to formaldehyde caused greater inactivation of the toxins than did formaldehyde alone. The reactions appear the olefinic double bond of the terminal furane ring and oxidation involving the phenol formed on opening of the lactone ring.

L- α-alanine의 미셀化를 위한 臨界濃度에 關한 硏究(Ⅵ)

張香東 서울産業大學校 1978 논문집 Vol.11 No.1

The studies on the critical concentrations for Micellization of L- α-alanine The Critical concentrations of L- α-alanine for micellization have been determined by the surface tension measurments in acid and alkali solutions, and also by the dye titration using Rhodamine, 6G in alkali solutions. The critical concentrations for micelle formation obtained by the above two methods shows the good agreement within experimental errors. Since L- α-alanine is an ampholyte, it may aggregate to form the micelles in both acidic and basic media than its isoelectric points. The basic media was found the good for the micelle formation than acidic media. The effect of gegen ions upon critical concentrations for micellization in alkaline media is similar to that expected from the salts effect on critical micelle concentrations.

Benzyl chloride와 Mercurous nitrate의 反應에 關한 反應速度論的 硏究 (第Ⅳ報)

張香東 서울産業大學校 1976 논문집 Vol.9 No.1

The kinetics of the reaction of m-or p-substituted benzyl chlorides with mercurous nitrate in acetonitrile at 25° were determined by an electric conductivity method. According to a plot of log k against the Hammett substituent constants, C-Cl bond cleavage in benzyl chloride is postulated to be a rate determining step at the SN₂ reaction of benzyl chloride with mercurous nitrate. Both electron-donation substituents and electron-withdrawing substituents quantitatively affected the rate of reaction, but each in a different manner. A mechanistic possibility was proposed to account for the results and some activation parameters were also calculated.

Alanine 誘導體의 合成에 關한 硏究(第IV報) (L-α-alanine과 Oxaly Chloride의 反應 및 그 誘導體의 合成)

張香東 서울産業大學校 1975 논문집 Vol.8 No.1

Synthesis of L-α-alanine derivatives have been attempted, as a part of the study for the oxaly derivatives of L-α-amino acids. Oxanily L-α-alanine has been synthesized from L-α-alanine and oxanily chlor ide in tetrahydrofurane, and it has been, also, synthesized by direct reaction of L-α-alanine, aniline and oxalyl chloride in dioxane. Oxalyl L-α-alanine methyl ester has been synthesized from the reaction of L-α-alanine methyl ester and oxalyl chloride in benzene, and it has been, also, synthesized by direct reaction of L-α-alanine and oxalyl chloride in dioxane medium. When the resulting products are confirmed through the element analysis and infrared spectroscopy.

A flatoxin B_1의 化學的 脫毒素化에 關한 硏究(第Ⅳ報)

張香東 단국대학교 대학원 1981 學術論叢 Vol.5 No.-

On acidification of aflatoxin B_1, the lactone ring in reformed and can be extracted with chloroform (2nd report). After hydrogen peroxide treatment of the aflatoxin B_1 in alkaline medium can not be extracted by chloroform. This process dependent upon the opening of the lactone ring in pure crystall aflatoxin B_1 are effectively distroyed on pH=9 and pH=10, 100℃, and 0.125M―H_2O_2 The lactone ring of aflatoxin B_1 opens in the hydrogen peroxide by alkaline medium to yield the carboxyl and hydroxyl group. The separation of opened compound was carried out by elution chromatography. The identification of opened compound was determined to molecular weight by titration and Rast method, and it was confirmed by infrared spectroscopy.

Benzyl Nitrate로부터 Aldehyde 및 Acetate 轉換에 關한 硏究(第Ⅲ報)

張香東 서울産業大學校 1974 논문집 Vol.7 No.1

Benzyl nitrate was not only converted to benzaldehyde but also acetate in acetic acid containning a catalytic quantity of sulfuric acid. And it was, also,converted to aldehyde and acetate in toluene,tetrahydrofurane and dioxane. It colud be recovered unchanged after a solution in toluene was refluxed for 5 hr, One-third of the nitrate was converted to acetate, but no aldehyde was formed. The strong acid was an essential ingredient for aldehyde formation. The acctic acid solvent, on the other hand was not essential ingredient for aldehyde formation. But, it was an essential ingredient for acetate formation.

Aflatoxin B₁의 化學的 脫毒素化에 關한 硏究(第Ⅴ報)

張香東 서울産業大學校 1981 논문집 Vol.15 No.1

Oxidation of aflatoxin B₁by ozone (ozonized oxygen) at -78°C in chloroform gave the exo 2,3 -oxide (epoxide) on dluble bond of the terminal furane ring. The chloroform was removed in a stream of nitrogen and the residue was separated by elution column chromatography. The epoxide was identified by infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and determined to molecular weight by Rast method. The result by elemental analysis of the resulting product was well agreed with calcd value and found value.

아플라톡신 B₁의 化學的 脫毒素化에 關한 硏究 (第Ⅷ報)

張香東 서울産業大學校 1986 논문집 Vol.24 No.1

아플라톡신 B₁의 脫毒素化를 위한 가장 믿을만한 實際的인 接近方法의 하나로서 溫度를 上昇시킨 條件下에서 水酸化암모늄으로 反應을 시켰다. 이때에 生成된 二次化合物을 赤外線 및 紫外線 分光 光度計, 그리고 水素核磁氣 共鳴 및 質量 分析 分光器로 名名 測定한 結果에 依하면 dihydro-4-hydroxy-6-methoxyfuro-[2, 3-b] - benzofuran 임이 確認되었다. 本 實驗에서는 암모니아化시켜 二次的으로 生成된 物質 分離 및 그 特性을 記述하면 分子量 206 化合物의 非螢光性 페놀은 아폴라톡신 D₁의 構造와 類似하지만 시클로펜텐온 고리가 없다는 것이다. One of the most promising practical approaches to detoxification of aflatoxin B₁reacted with ammonium hydroxide under elevated temperature. A second compound was identified as dihydro-4-hydroxy-6-methoxyfuro[2,3-b]-benzofuran by infrared, ultraviolet, proton nuclear magnetic resonance and mass spectrometry. This article describes the separation and characterization of a second major ammoniation product, a nonfluorescent phenol of molecular weight 206 which is similar in structure to aflatoxin D₁, but lacks the cyclopentenone ring.