Elektrochemische Carboxylierung substituierter Vinylketone

Electrochemical Carboxylation of Substituted Vinyl Ketones α-Chlor-β-acyl-vinylsulphides ( 1a–f ) and keten-S, N-acetales ( 3a,b ) are reduced in the presence of CO₂ at the cathode to yield the corresponding acids ( 4a–f resp. 5). Whereas the carboxylation of 1 proceeds via elimination-addition mechanism, the reduction of 3 is similar to the keten-S, S-acetales described earlier an EC (addition) EC (elimination) sequence.     

1,1-二(4-羟基苯基)环辛烷的合成

以环辛酮和苯酚为原料,β-巯基丙酸为助催化剂,通人干燥的氯化氢气体在常温常压下反应制得标题化合物,其结构经红外、核磁共振氢谱和质谱确认正确.研究表明:氯化氢气体催化效果明显好于其他酸催化剂,硫醇/酚类化合物是有效的助催化剂,加热对反应不利.最佳反应条件为:n(环辛酮)∶n(苯酚)∶n(β-巯基丙酸)=1∶5∶0.1,干燥氯化氢气氛,无溶剂条件下,室温常压反应5d,产率81.0％.     

Syntheses and radical ring-opening polymerizations of 1,1-bis(hydroxymethyl)-2-vinylcyclopropane and 1,1-bis(methoxymethyl)-2-vinylcyclopropane

Homo- and copolymerizations of 1,5-hexadiene with ethene and styrene using halfsandwich metallocene catalyst Me₂Si(Me₄Cp)(N-tert.-butyl)TiCl₂/MAO (Cp = cyclopentadienyl, Me = methyl, MAO = methylalumoxane) were investigated. According to ¹³C-NMR spectroscopic microstructure analysis, cyclopolymerization of 1,5-hexadiene afforded randomly distributed cis- and trans-cyclopentane rings in the homo- and copolymer backbone. 1,5-hexadiene incorporation reached 52 mol-%. The ratio of vinyl side chains to cyclopentane rings was controlled by 1,5-hexadiene concentration, where low 1,5-hexadiene concentration promoted cyclopolymerization. Copolymer glass transition temperatures increased with increasing content of cyclic units in the backbone. Styrene was used successfully as termonomer in ethene/1,5-hexadiene polymerization, resulting in a semicrystalline terpolymer with cyclic and styrenic units in the polymer backbone. Received: 5 September 1996/Accepted: 11 November 1996     

Elektrochemische Synthese von (E)-Thiokohlensäure-S-ethenyl-O-ethyl-diestern

Electrosynthesis of (E)-Ethenyl-O-ethyl-thiocarbonates Electrochemical reductions of 4-aryl- and 4,5-diaryl-1,2,3-thiadiazols ( 1 – 5 ) in acetonitrile/0,1 M tetraalkylammonium-supporting-electrolyte at Hg-cathodes in the presence of ethylchloroformiate (CAE) yield (E)-S-(2-aryl) ethenyl- and S-(1,2-diaryl)ethenyl-O-ethyl-thiocarbonates ( 1a – 5a ). The S-carboxylation proceeds via preformation of cyclic-voltammetric- and ¹H-nmr-provable CAE-complexes, ring-opening and N₂-elimination in a two-electron reduction. The synthesis including a rearrangement of a N-tos-S-CAE-complex is discussed in context with CNDO/2 quantum chemical calculation. Thermochemical synthesis of this new class of thiocarbonates proved unsuccessful.     

1,1-二甲硫基-2-硝基乙烯的合成

研究了以硝基甲烷和二硫化碳为原料,合成1,1-二甲硫基-2-硝基乙烯。考察了反应温度、反应时间、甲基化试剂、溶剂、投料比等对于反应产物的影响,得到优化工艺条件为:反应温度35℃,反应时间3h。以硫酸二甲酯为甲基化试剂,常温下反应时间3 h,重结晶得1,1-二甲硫基-2-硝基乙烯,收率为84%,产物通过IR、1H-NMR鉴定。     

Elektrochemische Reduktion von Trichloracetaldehyd-Olefin-Additionsprodukten

Electrochemical Reduction of Trichloroacetaldehyde-Olefin-Addition-Products Trichloroacetaldehyde reacts with different olefins forming addition products. In most cases this reaction results in 1, 1, 1-trichloro-2-hydroxy compounds (2a–d) . But also a different route of reaction is possible. Thus 2, 3-dimethylbut-1-ene (1e) forms 4-trichloro-1, 1, 2-tetrahydroxy-furane (2e) and cyclohexene (1f) forms 3-trichloromethyl-2-oxabicyclo-2, 2, 2-octane (2f) . All addition products are suitable starting materials for electrochemical conversions. In acidic electrolytes, on lead cathodes the electrochemical reduction results in a simultaneous cleavage of a C Cl and a C O bond to form the CHCCl₂-group (3a-f) . In neutral electrolytes, on mercury cathodes, however, a reductive conversion of a CCl₃ – group to a CHCl₂-group takes place ( 4c , 4f ).     

Elektrochemische Adamantylierung von Styrylpyridinen

Electrochemical Adamantylation of Styrylpyridines The reaction between electrochemically generated anion radicals of the 4-(4-styryl)-pyridines 1–6 and 1-bromoadamantane gives, in solvents of low proton availability as N, N dimethylformamide via an electron transfer in solution and formation of 1-adamantyl-radicals, monoadamantylated pyrid-4-yl-phenylethanes. The major product results from an anion radical/radicalcoupling in the 2(β)- next the 1(α)-position. A competing pathway of the electrohydroadamantylation is the hydrogeneration of the  CHCH double bond, whose importance increases with the water content of the solvent. Based on cyclic-voltammetric evidence and product distribution, the mechanism of the reductive coupling of 1–6 in the presence of 1-bromoadamantane in discussed in terms of indirect electrolysis.     

Elektrochemische Darstellung von organischen Diseleniden

Electrochemical Preparation of Organic Diselenides By the method of electrosynthesis a number of organic diselenides can be prepared simply and without danger. The cathodic polarisation of a special selenium electrode in aprotic solutions gives rise to polyselenideanions, which react with electrophilic compounds to the corresponding diselenides of the general formula RSeSeR ( 2a–e ) with R = benzyl, 2-nitrophenyl, cyclohexyl, isopropyl, 4-cyanophenyl.     

Elektrochemische Adamantylierung von reduktiv dehalogenierbaren Chinolinen

Electrolytic Adamantylation by Reductive Coupling of Quinolinylhalides in the Presence of 1-Bromoadamantane Electrochemically generated anion radicals of a number of halogen-substituted quinolines 1 a–g dehalogenate in N,N-dimethylformamide to halogen anions and radicals, which may stabilize by hydrogen abstraction from the solvent. In the presence of 1-bromoadamantane the fragments of reductive dehalogenation may be used synthetically for indirect generation of 1-bromoadamantane-radicals, which react predominantly to cross-coupled 2- and 7-monoadamantylated dihydroquinoline- and quinoline-structures, independent of the original halogen position. If C-2 is blocked, adamantylation takes place in the carbocyclic ring. Product distribution and cyclic-voltammetric results are discussed in terms of mechanism.     

Elektrochemische untersuchungen von 3-imidazolin-5-thionen

The electrochemical behaviour of some methyl-, tert. butyl- and phenyl-substituted derivatives of 3-imidazoline-5-thiones has been examined by polarography and voltammetry in acetonitrile. Based on these data and on preparative electrolysis a mechanism for both the reduction and oxidation and the N → S benzoyl group migration is presented.     

齐格勒-纳塔催化剂内给电子体1,1-双(甲氧甲基)环己烷的合成

以环己酮为起始原料,经Darzens反应、水解酸化、脱羧重排、缩合歧化及醚化反应合成了1,1-双(甲氧甲基)环己烷,并考察了反应中原料物质的量的比、脱水剂无水Na2SO4用量等关键因素的影响。在适宜的反应条件下,以环己酮计,目标产品的总收率为61.6%,气相色谱纯度为95.3%。1H-NMR分析表明所获产品结构正确。     

Synthese und Reaktionen von 2-[Bis-(alkylthio)-methyliden]-indan-1,3-dionen

Synthesis and Reactions of 2-[Bis-(alkylthio)-methyliden]-indan-1,3-diones The 2-[bis-(alkylthio)-methyliden]-indan-1,3-diones 3 and especially the methyl-compound 3a react with nucleophiles by substitution of the CH₃ S group. The reaction with amines are yields the S,N or N,N-acetales 7 and 8 , respectively. Diamines, amino hydroxy- or amino-mercapto compounds as dinucleophiles give the cyclic compounds 9 or the condensed heterocycles 12 and 16 , where the carbonyl group has been integrated in the cyclisation. Also carbanions react with 3a under substitution. The structures of the final products are determined with ir-, ¹H-n.m.r.- and ms-spectra.     

Copolymers of 3,3′,4,4′-tetraaminobiphenyl and 1,2,4,5-tetraaminobenzene with 1,1′-bis(glyoxalyl)-ferrocene and 1,1′-bis(phenylglyoxalyl)ferrocene

Four monomers were synthesized and four copolymers prepared. The polymers were dark-colored, poorly soluble, crystalline products. The x-ray photographs were typical of triclinic crystals. The polymers degraded at temperatures lower than those characteristic of the analogous homopolymers. The recovered polymers were ferromagnetic.     

Elektrochemische Darstellung von O,O-Diorgano-O-(2, 2-dichlorvinyl)-phosphorsäureestern

Electrochemical Synthesis of 2, 2-Dichloroethenyl-dialkyl-phosphoric Acid Esters The reaction of O-1,2,2,2-tetrachloroethyl phosphorodichloridate 3 with alcohols or phenols gives symmetrical or unsymmetrical O, O-diorgano-O-1,2,2,2-tetrachloroethyl phosphates 2 , which can be reduced electrochemically. In this reaction two vicinal chlorine atoms are eliminated. This reaction results in compounds with high biological activity, especially as insecticides. The synthesis and the polarographic behaviour of various O, O-di-organo-O-1,2,2,2-tetrachloroethyl phosphates 2 as well as the preparative techniques of the electrochemical elimination of chlorine are described.     

Push-pull-Butadiene. XII. Darstellung von Hetrocyclen aus 2,6-Bis[bis(alkylthio)methylen]cyclohexylidenmalononitrilen

Preperations of Heterocycles by using of 2,6-Bis[bis(alkylthio)methylene]cyclohexylidenemalononitriles . 2,6-Bis[bis(alkylthio)methylene]cyclohexylidenemalonitriles 1 react with alkanethioles to give 1,3-bis(alkylthio)-5-[bis(alkylthio)methylene]-5,6, #7,8-tetrahydro-isoquinoline-4-carbonitriles 2 . Treatment of 1 with hydrogen bromide yields 4,6,7,9-tetrakis(alkylthio)-2,3-dihydro-5,8-diaza-phenalenes 3 . On the other hand, 1 can be converted with bromine to 6,9-bis(alkylthio)-4,7-dibromo-2,3-dihydro-5,8-diaza-phenalenes 5 . However, the reaction of 1 and N-bromosuccinimide afforded 2,6-bis[bis(alkylthio)methylene]-3-bromo-cyclohexylidenemalononitriles 8 .