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《合成化学》2010,(Z1)
以绿色合成为目标的方法和技术是目前有机合成化学研究的重要内容。水相中的有机电化学合成兼有水相有机合成和有机电化学合成两种方法的优点,是一种重要的绿色合成技术,也是目前绿色化学研究的热点之一。研究表明,水相中邻苯二酚电化学氧化生成邻苯醌,该中间体非常活泼,可以与双烯发生[4+2]环加成反应生成烯酮衍生物,或者在亲核试剂的作用下,发生Michael加成反应生成取代邻苯二酚或者苯并杂环衍生物,而这些化合物常常具有各种抗菌、抗病毒(包括HIV)、抗肿瘤、保肝、扩冠等重要的生理作用。因此,水相中邻苯醌的电化学合成及其原位转化是一种有效的合成多羟基芳香化合物及其衍生物的方法。考虑到很多多羟基芳香化合物具有抗HIV整合酶的潜在活性,近三年来,我们开展了多羟基芳香族化合物电化学合成工作。本报告将简单介绍本课题组在这一方面的研究结果。 相似文献
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Electrochemical oxidation of catechol and its derivatives ( 1a–d ) has been studied in the presence of 4‐amino‐3‐thio‐1,2,4‐triazole ( 3 ) at various pHs. Some electrochemical techniques such as cyclic voltammetry using the diagnostic criteria derived by Nicholson and Shain for various electrode mechanisms and controlled‐potential coulometry were used. Results indicate the participation of catechols ( 1a–d ) with 3 in an intramolecular cyclization reaction to form the corresponding 1,2,4‐triazino[5,4‐b]‐1,3,4‐thiadiazine derivatives. In various scan rates, based on an electron transfer–chemical reaction–electron transfer–chemical reaction mechanism, the observed homogeneous rate constants (kobs) for Michael addition reaction were estimated by comparing the experimental cyclic voltammetric responses with the digital simulated results. The oxidation reaction mechanism of catechols ( 1a–d ) in the presence of 4‐amino‐3‐thio‐1,2,4‐triazole ( 3 ) was also studied. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 340–345, 2007 相似文献
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Rajendra Prasad Korivi Dr. Chien‐Hong Cheng Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(1):282-287
An efficient short total synthesis of benzo[c]phenanthridine alkaloids including oxyavicine, oxynitidine, and oxysanguinarine is described. Thus, N‐methyl‐o‐bromobenzaldimines 1 b – d undergo regioselective cyclization with 4‐(benzo[d][1,3]dioxol‐5‐yl)but‐3‐yn‐1‐ol ( 2 b ) in the presence of [Ni(cod)2] (cod=1,5‐cyclooctadiene). In situ oxidation of the resultant isoquinolinium salts gives isoquinolinone derivatives 5 b – d with benzo[d][1,3]dioxol‐5‐yl substitution at the C3 atom and a (CH2)2OH group at the C4 atom. Later, oxidation of the alcohol group in 5 b – d to the aldehyde moiety followed by acid‐catalyzed cyclization and dehydration completes the total syntheses to give oxyavicine, oxynitidine, and oxysanguinarine in 67, 65, and 60 % yields, respectively. The synthesis requires four steps from o‐bromobenzaldehyde derivatives. Transformations of these alkaloids to the other alkaloids in this family are also discussed herein. 相似文献
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Mojtaba Shamsipur Saied Saeed Hosseiny Davarani Davood Nematollahi 《Journal of heterocyclic chemistry》2006,43(6):1673-1677
Electrochemical oxidation of catechol and some of 3‐substituted catechols ( 1a‐c ) has been studied in the presence of ethyl‐2‐chloroacetoacetate ( 3 ) in water/acetonitrile (90:10) solution using cyclic voltammetry and controlled‐potential coulometry. The results indicate that the quinones derived from catechols ( 1a‐c ) participate in Michael addition reactions with ethyl‐2‐chloroacetoacetate( 3 ), with consumption of only two electrons per molecule of 1 , to form the corresponding benzofurans ( 10a‐c ). The electrochemical synthesis of benzofurans ( 10a‐c ) has been successfully performed at a carbon rod electrode and in an undivided cell with good yields and purity. A new two‐electron mechanism for the electrode process is proposed. 相似文献
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The electrochemical oxidation of 3,4‐dihydroxy benzoic acid ( 1 ) has been studied in the presence of 6‐methyl‐1,2,4‐triazine‐3‐thione‐5‐one ( 2 ) in aqueous solution. The oxidation mechanism of 1 and its reaction in the presence of 2 was offered. It was confirmed that 1 is converted to 7H‐thiazolo[3,2‐b]‐1,2,4‐triazin‐7‐one derivative 5 through Michael addition reaction of 2 to anodically generated o‐benzoquinone. The results of the research were used for electrochemical synthesis of 5 in an undivided cell in good yield and purity. 相似文献
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Grgory Malais Werner Bonrath Manfred Breuninger Thomas Netscher 《Helvetica chimica acta》2006,89(4):797-812
Ru‐Catalyzed olefin cross‐metathesis (CM) has been successfully applied to the synthesis of several phytyl derivatives ( 2b, 2d – f, 3b ) with a trisubstituted C?C bond, as useful intermediates for an alternative route to α‐tocopheryl acetate (vitamin E acetate; 1b ) (Scheme 1). Using the second‐generation Grubbs catalyst RuCl2(C21H26N2)(CHPh)PCy3 (Cy = cyclohexyl; 4a ) and Hoveyda–Grubbs catalyst RuCl2(C21H26N2){CH‐C6H4(O‐iPr)‐2} ( 4b ), the reactions were performed with various C‐allyl ( 5a – f, 7a,b ) and O‐allyl ( 8a – d ) derivatives of trimethylhydroquinone‐1‐acetate as substrates. 2,6,10,14‐Tetramethylpentadec‐1‐ene ( 6a ) and derivatives 6c – e of phytol ( 6b ) as well as phytal ( 6f ) were employed as olefin partners for the CM reactions (Schemes 2 and 5). The vitamin E precursors could be prepared in up to 83% isolated yield as (E/Z)‐mixtures. 相似文献
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This article deals with isomeric ruthenium complexes [RuIII(LR)2(acac)] (S=1/2) involving unsymmetric β‐ketoiminates (AcNac) (LR=R‐AcNac, R=H ( 1 ), Cl ( 2 ), OMe ( 3 ); acac=acetylacetonate) [R=para‐substituents (H, Cl, OMe) of N‐bearing aryl group]. The isomeric identities of the complexes, cct (cis‐cis‐trans, blue, a ), ctc (cis‐trans‐cis, green, b ) and ccc (cis‐cis‐cis, pink, c ) with respect to oxygen (acac), oxygen (L) and nitrogen (L) donors, respectively, were authenticated by their single‐crystal X‐ray structures and spectroscopic/electrochemical features. One‐electron reversible oxidation and reduction processes of 1 – 3 led to the electronic formulations of [RuIII(L)(L ? )(acac)]+ and [RuII(L)2(acac)]? for 1 +‐ 3 + (S=1) and 1? – 3? (S=0), respectively. The triplet state of 1 +‐ 3 + was corroborated by its forbidden weak half‐field signal near g≈4.0 at 4 K, revealing the non‐innocent feature of L. Interestingly, among the three isomeric forms ( a – c in 1 – 3 ), the ctc ( b in 2 b or 3 b ) isomer selectively underwent oxidative functionalization at the central β‐carbon (C?H→C=O) of one of the L ligands in air, leading to the formation of diamagnetic [RuII(L)(L ′ )(acac)] (L ′ =diketoimine) in 4 / 4′ . Mechanistic aspects of the oxygenation process of AcNac in 2 b were also explored via kinetic and theoretical studies. 相似文献
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Yuewei Wu Chaoxian Yan Dongxu Li Chengshan Yuan Jibin Sun Shuyun Zhou Hao‐Li Zhang Xiangfeng Shao 《化学:亚洲杂志》2019,14(10):1860-1869
Four tetraphenylethylenes ( 2 a – d ) containing an electron‐rich 2,3,4,6‐tetrahydro‐1,6‐dithia‐3a‐azaphenalene (THDTAP) moiety have been synthesized. The 2 a – d show aggregation‐induced emission (AIE) with yellowish green photoluminescence (PL) in THF‐H2O (v/v, 1:9) solution and in the solid state. Compounds 2 a – d undergo 1,2‐migratory shift in oxidative cyclodehydrogenation reactions to afford the unexpected products 3 a – d which display green PL in CH2Cl2 solution and are non‐emissive in the solid state. The PL intensities of 3 a – d are clearly enhanced in the presence of meta‐chloroperoxybenzoic acid (mCPBA) owing to the oxidation of the S‐atoms on the THDTAP moiety. In contrast, the PL of 2 a – d in THF‐H2O (v/v, 1:9) solution is quenched by adding mCPBA, ascribable to the oxidation of the C=C bond on the ethylene moiety. It is found that the absorption of 3 a – d is distinctly red‐shifted from the UV/Vis region to the NIR region upon acidification, arising from the protonation of the N‐atom on the THDTAP moiety. Furthermore, 3 a – d display nonlinear optical response (NLO) and optical limiting (OL) behaviour which is superior to that of the well‐known OL material C60. 相似文献
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Influence of Halogen Substitution in the Ligand Sphere on the Antitumor and Antibacterial Activity of Half‐sandwich Ruthenium(II) Complexes [RuX(η6‐arene)(C5H4N‐2‐CH=N‐Ar)]+ 下载免费PDF全文
Joel M. Gichumbi Bernard Omondi Geraldine Lazarus Moganavelli Singh Nazia Shaikh Hafizah Y. Chenia Holger B. Friedrich 《无机化学与普通化学杂志》2017,643(11):699-711
New complexes [(η6‐p‐cymene)Ru(C5H4N‐2‐CH=N–Ar)X]PF6 [X = Br ( 1 ), I ( 2 ); Ar = 4‐fluorophenyl ( a ), 4‐chlorophenyl ( b ), 4‐bromophenyl ( c ), 4‐iodophenyl ( d ), 2,5‐dichlorophenyl ( e )] were prepared, as well as 3a – 3e (X = Cl) and the new complexes [(η6‐arene)RuCl(N‐N)]PF6 (arene = C6H5OCH2CH2OH, N‐N = 2,2′‐bipyridine ( 4 ), 2,6‐(dimethylphenyl)‐pyridin‐2‐yl‐methylene amine ( 5 ), 2,6‐(diisopropylphenyl)‐pyridin‐2‐yl‐methylene amine ( 6 ); arene = p‐cymene, N‐N = 4‐(aminophenyl)‐pyridin‐2‐yl‐methylene amine ( 7 )]. X‐ray diffraction studies were performed for 1a , 1b , 1c , 1d , 2b , 5 , and 7 . Cytotoxicities of 1a – 1d and 2 were established versus human cancer cells epithelial colorectal adenocarcinoma (Caco‐2) (IC50: 35.8–631.0 μM), breast adenocarcinoma (MCF7) (IC50: 36.3–128.8.0 μM), and hepatocellular carcinoma (HepG2) (IC50: 60.6–439.8 μM), 3a – 3e were tested against HepG2 and Caco‐2, and 4 – 7 were tested against Caco‐2. 1 – 7 were tested against non‐cancerous human epithelial kidney cells. 1 and 2 were more selective towards tumor cells than the anticancer drug 5‐fluorouracil (5‐FU), but 3a – 3e (X = Cl) were not selective. 1 and 2 had good activity against MCF7, some with lower IC50 than 5‐FU. Complexes with X = Br or I had moderate activity against Caco‐2 and HepG2, but those with Cl were inactive. Antibacterial activities of 1a , 2b , 3a , and 7 were tested against antibacterial susceptible and resistant Gram‐negative and ‐positive bacteria. 1a , 2b , and 3a showed activity against methicillin‐resistant S. aureus (MIC = 31–2000 μg · mL–1). 相似文献
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A Facile and Efficient One‐Pot Electrochemical Synthesis of Thiazole Derivatives in Aqueous Solution 下载免费PDF全文
Mohsen Ameri Ali Amoozadeh Alireza Asghari Davood Nematollahi Mohammad Bakherad 《Helvetica chimica acta》2015,98(2):210-223
In the present work, the electrooxidation of hydroquinones 1a and 1b , and catechols 1c and 1d was studied in the presence of rhodanine ( 3 ) as nucleophile in a mixture of EtOH and phosphate buffer solution as ‘green’ media using cyclic voltammetry and controlled‐potential coulometry. The results indicated that the corresponding p‐ and o‐quinones formed from the hydroquinones and catechols, respectively, participate in Michael addition reaction to yield new thiazole derivatives. The electrochemical syntheses of these new thiazole derivatives were performed successfully at three graphite rod electrodes in undivided cells in good‐to‐excellent yields at room temperature without any catalyst. 相似文献