铁卟啉催化氧化萘酚合成2-羟基-1,4-萘醌

羟基萘醌;铁卟啉催化氧化萘酚合成2-羟基-1;4-萘醌     

金属卟啉催化氧化萘酚 Ⅰ.2-羟基-1,4-萘醌的制备

羟基萘醌;金属卟啉催化氧化萘酚 Ⅰ.2-羟基-1;4-萘醌的制备     

2-羟基-1,4-萘醌的合成及铁卟啉-氧催化中间体形成平衡常数的测定

铁卟啉催化剂;羟基萘醌;2-羟基-1;4-萘醌的合成及铁卟啉-氧催化中间体形成平衡常数的测定     

2,3-二取代-1,4-萘醌的合成

常温下, 在丙酮与水的混合介质中(V∶V＝1∶1), 4-羟基香豆素类化合物与1,4-萘醌进行Michael加成反应, 生成6个未见文献报道的2,3-二取代-1,4-萘醌. 产物经MS, 1H NMR, 元素分析表征, 确定了其化学结构.     

金属卟啉催化萘酚过氧化氢氧化(Ⅱ)──制备2-羟基-1,4-萘醌的氧化机理研究

在低温碱性甲醇溶液中一氯化四苯基卟啉铁催化萘酚H₂O₂氧化高选择性地制取2-羟基-1,4-萘醌(HNQ),以2-萘酚和1-萘酚为底物时HNQ的最高产率分别为57%和40%(纯度>95%).根据金属卟啉催化氧化反应的特性,采用UV-Vis和EPR现场光谱监测催化剂和反应物的光谱变化,提出了羟基游离基加成反应机理.     

2-甲基-1,4-萘醌的绿色合成方法

以2-甲基萘(2-MN)为原料、H₂O₂为氧化剂,经不同酸(硫酸、氢溴酸、三氟乙酸等)催化合成2-甲基-1,4-萘醌(2-MNQ),其结构经¹H NMR和¹³C NMR确证,其纯度经HPLC检测。对反应条件进行了优化。最佳反应条件为：20 eq. CH₃COOH为溶剂,6 eq. H₂O₂为氧化剂,在10%mol H₂SO₄催化下,于75 ℃反应,2-MNQ纯度95%,收率67%。     

2-甲基-1,4-萘醌对DNA光敏损伤的诱导作用

选择波长337 nm的激光作为激励光源,借助凝胶电泳研究了2-甲基-1,4-萘醌诱导的DNA光敏损伤.结果表明:在氧气饱和、脱氧条件下光敏损伤显著,DNA损伤主要与光子剂量、核酸与萘醌浓度比及DNA存在形式有关.     

气相色谱法测定直接电氧化反应液中2-甲基萘和2-甲基-1,4-萘醌

建立了气相色谱同时测定反应液中的2-甲基萘和2-甲基-1,4-萘醌的方法.该法以萘为内标物,在DB-1色谱柱上进行分离,氢火焰离子化检测器.方法的回收率98%～102%,相对标准偏差小于2%.     

2-羟基-1,4-萘醌的电化学氧化还原机理研究

利用现场红外光谱电化学方法、 红外光谱循环伏吸法(CVA)和导数循环伏吸法(DCVA)研究了2-羟基-1,4-萘醌(2-HNQ)在乙腈溶剂中的电子转移机理. 在扫描范围为0.2~-1.8 V时, 2-HNQ的循环伏安(CV)图中有2对氧化还原峰. 在扫描范围为1.0~-2.0 V时, CV图在更正的电位下会出现1个氧化峰. 通过分析循环伏安扫描过程中1656, 1495, 1549和1325 cm^-1等峰的变化, 观察到整个电化学过程中存在2种中间状态, 去质子化醌(Q-O^-)还原生成的自由基二价阴离子会继续发生电化学反应, 即Q-O^-的还原遵循电化学-电化学反应机理(EE机理). 红外分析结果表明, 2-HNQ的电化学过程中存在较强的氢键作用.     

1, 2-萘醌-4-磺酸钠分光光度法测定间苯二酚

在pH 13.00缓冲溶液中, 间苯二酚能够催化氢氧根离子与1,2-萘醌-4-磺酸钠反应生成2-羟基-1, 4-萘醌, 其最大吸收波长为454 nm. 间苯二酚质量浓度在0.39～13.21 mg/L范围内与吸光度呈现良好线性关系. 线性回归方程为A=0.01918+0.05703c (×105 mol/L), 相关系数r=0.9981. RSD和检测限分别为1.6%, 0.34 mg/L (3σ/k). 该法能够直接用于水样中间苯二酚含量测定, 回收率在94.3%～106%.     

Reaction of 2-mercaptobenzimida(thia)zole with 1,4-naphthoquinone and its oxide

The reaction of 2-mercaptobenzimida(thia)zole with 1,4-naphthoquinone proceeds as nucleophilic 1,4-addition to give the corresponding thioethers. The reaction of 1,4-naphthoquinone oxide with 2-mercaptobenzimidazole leads to benzimidazonaphthothiazole, while the reaction of the oxide with 2-mercaptobenzothiazole leads to a thioether as a consequence of the addition of the mercapto-substituted heterocycle at the oxide ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 121–124, January, 1992.     

Oxidation of 7-ethyl-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone (echinochrome A) by atmospheric oxygen 1. Structure of dehydroechinochrome

The nondestructive oxidation of 7-ethyl-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone by atmospheric oxygen in the ground (triplet ³Σ_g^–) and excited (singlet ¹Δ_g) states in different solvents (acetone, dioxane, ethanol, aqueous ethanol, water) at room temperature involves the initial formation of 7-ethyl-5,6,8-trihydroxy-2,3-dioxo-2,3-dihydro-1,4-naphthoquinone (dehydroechinochrome) accompanied by the release of an H₂O₂ molecule into the reaction medium. Dehydroechinochrome, being highly susceptible to hydration, successively reacts with two H₂O molecules to form 7-ethyl-2,2,3,3,5,6,8-heptahydroxy-2,3-dihydro- 1,4-naphthoquinone as the relatively stable final product. In this form, it can be isolated from the mixture of reaction products.     

Synthesis of 2-aminopentafluoro-1,4-naphthoquinone derivatives

Potential biologically active derivatives of 2-aminopentafluoro-1,4-naphthoquinone modified at the amino group were synthesized in 32–96% yield by reactions of hexafluoro-1,4-naphthoquinone with nitrogen-centered nucleophiles.     

Reactions of 1,4-naphthoquinone and 5-hydroxy-1,4-naphthoquinone with ninhydrin

Russian Chemical Bulletin - 1,4-Naphthoquinone and 5-hydroxy-1,4-naphthoquinone react with ninhydrin to give 2-(2-hydroxy-1,3-dioxo-2,3-dihydro-1H-inden-2-yl)naphthalene-1,4-dione and 8-hydroxy-...     

Photolysis of 2-amino- and 2-methylamino-1,4-naphthoquinone

Pyrex-filtered sunlight irradiation of solutions of 2-amino-1,4-naphthoquinone unexpectedly failed to produce cyclobutane dimers. Irradiation in acetic anhydride led to the formation of the trimeric 6-[3'-amino-2'-(1,4-naphthoquinonyl)]-dibenzo[b,h]carbazole-5,13:7,12-diquinone as well as 3,3'-diaraino-2,2'-bi-1,4-naphthoquinonyl and diben=zo[b,h]carbazole-5,13;7,12-diquinone. Similar treatment of 2-methyl=amino-1,4-naphthoquinone afforded 6-[3'-methylamino-2'-(1,4-naphthoqui=nonyl)]-dibenzo[b,h]carbazole-5,13:7,12-diquinone and 6-methyl-dibenzo=[b,h]carbazole-5,13:7,12-diquinone.     

Reaction of 2-chloro-3-(4-N,N-dimethylaminoanilino)-1,4-naphthoquinone with cyclic amines (piperidine,morpholine, and pyrrolidine)

It was shown that the reaction of 2-chloro-3-(4-N,N-dimethylaminoanilino)-1,4-naphthoquinone with piperidine in the absence of a solvent gives not only a product of replacement of the chlorine atom by a piperidino group, 3-(4-N,N-dimethylaminoanilino)-2-piperidino-1,4-naphthoquinone, but also 2-(4-N,N-dimethylaminoanilino)-1,4-naphthoquinone and 2-(4-N,N-dimethylaminoanilino-2-piperidino)-1,4-naphthoquinone. The latter compounds are the only reaction products formed in dimethyl sulfoxide. The reaction with morpholine occurs in a similar way, whereas that with pyrrolidine gives only a product of replacement of the chlorine atom by hydrogen.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2451–2454, December, 1995.     

Use of bis(oxazoline)-metal complexes as chiral catalysts for asymmetric Diels-Alder reactions using 2-acetyl-1,4-naphthoquinone as a dienophile

Asymmetric Diels-Alder reactions of 1,4-naphthoquinone and 2-acetyl-1,4-naphthoquinone with cyclopentadiene catalyzed by bis(oxazoline)-metal complexes afforded the corresponding Diels-Alder adducts. Moderate levels of enantiomeric excess were obtained and a number of different reaction conditions evaluated.     

Interaction of 2,3-dichloro-1,4-naphthoquinone with n-butylamine in halocarbon solvents

The rapid interaction between 2,3-dichloro-1,4-naphthoquinone (DClNQ) and n-butylamine results in the formation of 2N(n-butylamino)-3-chloro-1,4-naphthoquinone as the final product. The reaction is found to proceed through the initial formation of charge-transfer (CT) complex as an intermediate. The final product of the reaction has been isolated and characterized using FTIR, H1 and C13 NMR spectroscopy, mass spectrometry, and elemental analysis. The rate of formation of product has been measured as a function of time in different halocarbon solvents, viz., chloroform, dichloromethane and 1:1 (v/v) mixture of two solvents. The pseudo first order and second order rate constants at various temperatures for the transformation process were evaluated from the absorbance time data. The activation parameters (E(a), DeltaS#, DeltaH#, and DeltaG#) were obtained from temperature dependence of rate constants. The influence of dielectric constant on the properties of reaction was discussed and the probable course of reaction is presented.     

Synthesis and spectral properties of 1,4-naphthoquinone sulfanyl derivatives

Reactions of 2,3-dichloro-1,4-naphthoquinone with hexadecanethiol and other alkanethiols in ethanol in the presence of sodium carbonate afforded new symmetric and unsymmetrical sulfanylnaphthoquinone dyes.     

Synthesis of cis- and trans-5,8-dihydroxy-5,6,7,8-tetrahydro-1,4-naphthoquinone

Cis- and trans-5,8-dihydroxy-5,6,7,8-tetrahydro-1,4-naphthoquinone (1a, 1b) were for the first time synthesized from 5,8-dihydroxy-1,4-naphthoquinone (naphthazazine) (6) as a starting material and racemic triol (3) was first synthesized from 7. The configuration of 1a was determined by X-ray analysis.