Synthesis of gem-dialkoxycarbonylcyclopropane derivatives from olefins by the reaction with dibromomalonic esters and copper in dimethyl sulphoxide

A novel method for the synthesis of gem-dialkoxycarbonylcyclopropane derivatives is reported which involves the reaction of olefins with dibromomalonic esters and Cu in dimethyl sulphoxide. The reaction was applicable to a wide range of olefins and proceeded smoothly at moderate temperature to give the cyclopropane derivatives often in good yields. Cu was converted to Cu(II) bromide during the reaction. The reaction was weakly electrophilic and proceeded non-stereospecifically, and a stepwise mechanism involving addition and elimination appeared favourable for the reaction. In contrast, in the previously reported examples of the cyclopropanation of olefins by organic gem-dihalides and Cu in an aromatic hydrocarbon, Cu was converted to Cu(I) halides and a concerted cycloaddition of carbenoid intermediates appeared favourable.     

CuCl/I2催化末端烯烃与磺酰氯反应合成烯基砜类化合物研究

研究了用CuCl/I2催化一系列端基烯烃和磺酰氯反应合成烯基砜类化合物,反应体系中添加催化剂量的分子碘,可以大幅度提高该反应的产率,最高可获得97%的产率.同时,考察了各种铜盐的催化活性以及反应介质对反应的影响.     

Synthesis of new N-aminoaziridine derivatives by the addition of dibenzyloxycarbonylaminonitrene to olefins

In order to study the ring expansion of N-aminoaziridines into N-amino-5-membered heterocycles, N-(dibenzyloxycarbonylamino)aziridines were synthesized. N, N-Dibenzyloxycarbonylhydrazine was prepared. It was then oxidized with lead tetraacetate to a new diacylaminonitrene. This nitrene was added to various olefins to give the corresponding N-protected aminoaziridines. Cleavage of the protecting groups was realized for one example.     

Synthesis of olefins via a Wittig reaction mediated by triphenylarsine

An arsine-mediated Wittig reaction for the synthesis of olefins is described. After heating triphenylarsine in the presence of an activated alkyl bromide for 30 min, the resulting arsonium salt condensed with aldehydes in as little as 5 min at room temperature, yielding the olefins in high yields. Aromatic, heteroaromatic, and alkyl aldehydes were all suitable substrates for this process.     

Synthesis of N-propargylanabasine derivatives by the mannich reaction

N-Propargylanabasine derivatives bearing various substituents at the carbon atom of the alkyne fragment were obtained by the reaction of anabasine hydrochloride with terminal alkynes and paraformaldehyde. The reaction proceeded with retention of the C(2) chiral center in anabasine fragment. The by-products of the reaction, including 1,3-diacetylene (the products of dimerization of alkynes) and conjugated vinylacetylenes (the rearrangement products of the Mannich adducts) were isolated and characterized. Dedicated to Academician V. A. Tartakovsky in honor of his 75th anniversary. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1576–1585, August, 2007.     

Synthesis of novel 9-aryl and heteroarylpurine derivatives via copper mediated coupling reaction

A series of 9-(hetero)arylpurine derivatives has been prepared through N-arylation of 6-chloropurine with boronic acids in the presence of copper(II) acetate. Screening reaction conditions in terms of bases and solvents led to the successful coupling of a series of sterically demanding (hetero)arylboronic acids, never described so far. The coupling products were next readily converted into the target adenine derivatives. The described procedure provides easy access to original fragments for screening applications. Moreover these 9-aryl-6-chloropurine derivatives might be useful as intermediates for the preparation of purine derivatives with potential biological properties.     

Synthesis of carbostyril derivatives by reaction of aldehydes with oxazolines

Carbostyril derivatives are obtained on reaction of o-chlorobenzaldehyde and derivatives with 2-alkyl-4,4-dimelhyl-2-oxazolines with elimination of methallyl chloride. Phenylethenyloxazolines are presumed intermediates.     

Synthesis of indole derivatives from 2-bromoanilines by a palladium-assisted reaction

In the presence of palladium(II) acetate, 2-bromoanilines readily react with enamines such as N-vinyl-pyrrolidone or α-piperidinostyrene to produce indole derivatives.     

Synthesis of pyrimidine derivatives by the reaction of ketene dithioacetals with amides

Reactions of methyl 2-cyano-3,3-bis(methylthio)acrylate ( 1a ) with carboxamides 2a-g in the presence of sodium hydride in a mixture of benzene and N,N-dimethylacetamide took place displacement with the methylthio group to give the corresponding methyl 3-N-acylamino-2-cyano-3-(methylthio)acrylates 3a-g which were readily converted to the corresponding pyrimidine derivatives at reflux in methanol in good yields. Reactions of 2-cyano-3,3-bis(methylthio)acrylonitrile ( 1b ) with the carboxamides 2a-f gave directly pyrimidine-5-carbonitrile derivatives 7a-f . Ketene dithioacetals 1a,b smoothly reacted with thioamide 2g or urea 2h,i to give the expected pyrimidine derivatives 9,10a,b . Polyfunctionalized pyrimidines, thus obtained, were also used for the synthesis of fused pyrimidine derivatives.     

Synthesis of quinoline vinyl derivatives by the Mannich reaction

Aminomethylation of quinaldine and lepidine is investigated. Decomposition of quaternary salts of Mannich bases gives 2- and 4-vinylquinoline.     

Crystal structures of triazine-3-thione derivatives by reaction with copper and cobalt salts

The reaction of 5-methoxy-5,6-diphenyl-4,5-dihydro-2H-[1,2,4]triazine-3-thione L1H2OCH3 with copper(II) chloride leads to the formation of an organic molecule L2 containing two triazine rings linked by a new S-S bond. A binuclear copper(II) complex, 1, containing L1 is also isolated. The reaction of L1H2OCH3 with copper(I) chloride yields a hexanuclear cluster of copper(I), 2, in which the copper atoms form a distorted octahedron with the ligand L1 acting as an NS chelate and sulfur bridge, giving to the copper ion a trigonal geometry by one N and two S atoms. In any reaction of the disulfide L2 with metal salts, complexes containing this molecule are isolated. Reactions with copper(I) and copper(II) chloride and nickel(II) and cadmium(II) nitrate produce the S-S bond cleavage, giving complexes containing the triazine L1 behaving as the NS anion, which show spectroscopic characteristics identical with those formed by reaction with L1H2OCH3. However, the reaction with cobalt(II) nitrate gives a low-spin octahedral cobalt(III) complex, in which an asymmetric rupture of the disulfide L2 has been produced, giving an unexpected complex with a new ligand and keeping the S-S bond.     

Synthesis of polysubstituted olefins by Pd-catalyzed cross-coupling reaction of tosylhydrazones and aryl nonaflates

Aryl nonaflates are employed as electrophiles in the Pd-catalyzed cross-coupling with tosylhydrazones affording di-, tri-, and tetrasubstituted olefins. Fine tunning of the reaction conditions are required to accomplish the coupling successfully, including the addition of LiCl and the presence of small amounts of water. Under the optimized conditions, the reactions proceed with high yield and also high stereoselectivity depending on the nature of the coupling partners.     

Synthesis of selenocystine derivatives from cystine by applying the transformation reaction from disulfides to diselenides

A stepwise conversion of a disulfide (SS) to a diselenide (SeSe) bond through the corresponding iodide intermediate was implemented and was applied to the synthesis of selenocystamine and l-selenocystine derivatives from cystamine and l-cystine, respectively, in moderate yields.     

Synthesis of tetrahydrooxazole derivatives by reaction of 2-hydroxyethylhydrazones with paraformaldehyde

The condensation of 2-hydroxyethylhydrazones with paraformaldehyde gives N-substituted tetrahydrooxazoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 447–449, April, 197     

Synthesis of 1,3,4-thiazole derivatives by the reaction of thiobenzhydrazide with some acylacetylenes

2-Acylmethyl-5-phenyl- and 3-acylvinyl-2-acylmethyl-5-phenyl-1,3,4-thiadiazol-4-ines were obtained by the reaction of terminal -acetylenic ketones with thiobenzhydrazide. Substituted acetylenic ketones react with thiobenzhydrazide in alcohol to give N,S-bis(acylvinyl)thiobenzhydrazides.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 680–682, May, 1989.     

Alder-ene reaction of aryne with olefins

A novel intermolecular Alder-ene reaction based on aryne and olefins was developed. We performed this transformation under mild conditions such as at room temperature, and this reaction displayed high selectivity and good yields only in the presence of CsF. Hence, the intermolecular Alder-ene reaction of aryne with olefins provides an effective route to synthesize derivatives of olefins.     

The reaction of the trichloromethylium ion with olefins

The reactions of [CCl₃]⁺ with ethylene, 1-hexene, cyclopentence, cyclohexene and styrene have been studied in a field-free, high-pressure ion source by time-resolved ion collection following a short ionizing pulse of electrons. Ethylene is completely unreactive, while addition of [CCl₃]⁺ to the olefinic bond of the other compounds is followed by loss of one or more HCl molecules to give unsaturated cations. Only styrene forms a stable adduct [MCCl₃]⁺ which is an arenium ion produced by addition to the aromatic ring. Rate constants for the reaction of [CCl₃]⁺ have been determined and show that whereas reaction with styrene occurs at almost every ion-molecule collision, with 1-hexene and cyclopentene only 15% of the collisions lead to reaction.