EPR studies of copper(II) complexes with poly-2-methyl-5-vinyl-pyridine and poly-2-vinylpyridine

Cu(II) complexes of poly-2-vinylpyridine (P2VP) and poly-2-methyl-5-vinylpyridine (P2M5VP), partially quaternized by dimethylsulphate, and of the analogues (2-methyl-5-ethylpyridine, 2-ethylpyridine) were studied by EPR spectroscopy in a mixture of methanol and water. Peculiarities of the complex formation reaction were observed for the polymers compared to the analogues. At ratios of [Py]:[Cu²⁺] > 40, the predominant formation of tetrapyridinate-Cu(II) species [(CuL₄)]²⁺ was found for P2M5VP. However, differences were found between the parameters of EPR-spectra for the [CuL₄]²⁺ in the polymer from that of the [Cu(2M5EPy)₄]²⁺. It was suggested that, in the polymer, [CuL₄]²⁺ complexes with structure intermediate between square planar and tetrahedral are formed. Moreover, the maximum value of the pyridine fraction forming [CuL₄]²⁺ in P2M5VP was found to be about 10% and it is appreciably less the value of the fraction in P4VP (about 40%). For P2VP at [Py]:[Cu²⁺] > 40, an insignificant amount of [CuL₁]²⁺ and [CuL₂]²⁺ are formed in the solution. It follows that the main chain position relative to the ligand nitrogen atom in these polyvinylpyridines affects profoundly the complexation between the macromolecules and Cu(II) ions. The steric hindrances due to the chain are likely to change the [CuL₄]²⁺ structure and to prevent complex formation for P2VP.     

Cleavage of 2-methyl-5,6-dihydro-2h-pyrane by acid halides

The reaction of 2-methyl-5,6-dihydro-2H-pyrane with a number of acid halides in which the ring is cleaved is accompanied by an allylic rearrangement. The halogen atom in the isomers is replaced in the usual way by nucleophilic reagents, but aqueous alkali causes in addition the formation of 1,3,5-hexatriene and to a lesser extent recyclization to dihydropyrane.Translated from Khimiya Geterotsikhicheskikh Soedinenii, No. 12, pp. 1600–1602, December, 1984.     

Dynamics of lithium electrode passivation in aprotic organic electrolytes,studied by electrochemical noise method

Lithium electrode passivation is studied in different organic electrolytes, namely, 1 M LiClO₄ in 1,3-dioxolane, 1 M LiN(CF₃SO₂)₂ in 1,3-dioxolane, 1 M LiPF₆ in an ethylene carbonate-diethyl carbonate mixture, 1 M LiPF₆ in an ethylene carbonate-dimethyl carbonate mixture, using the electrochemical noise method. The dynamics of passive film formation on the lithium surface in the mentioned electrolytes that differ in their corrosivity towards lithium is followed.     

Reaction of combination of trimethylvinylsilane with organic halides catalyzed by palladium derivatives

Conclusions It has been discovered that halopyridines, halonaphthalene, iodocarborane, and aryl iodides are vinylated by a reaction of trimethylvinylsilane, catalyzed by palladium complexes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2342–2343, October, 1984.We wish to express our gratitude to E. I. Mysov for taking the chromato-mass spectra.     

Palladium-phosphine complex catalyzed cross-coupling reaction of 1-methyl-2-pyrrolyl-magnesium bromide and -zinc chloride with organic halides

1-Methyl-2-pyrrolyl-magnesium bromide and -zinc chloride, which were prepared from 1-methyl-2-pyrrolyllithium with MgBr₂ and ZnCl₂ respectively, reacted with aryl- and heteroaromatic halides to give the corresponding 2-substituted pyrroles in good to excellent yields in the presence of palladium-phosphine complexes as catalysts.     

The cross-coupling reactions of organic halides with organic derivatives of tin,mercury and copper catalyzed by palladium

The palladium-catalyzed cross-coupling of organic halides with organometallic compounds of tin, mercury and copper is discussed. It is shownn that the “ligandless” palladium complexes RPdXL₂ (L = solvent), in which solvent molecules act as weak donating ligands, are the most active catalysts for reactions of organotin compounds. It is found that nucleophilic catalysis is an efficient method of activatioin of organomercury and organocopper compounds in cross-coupling reactions. In the presence of iodide ion the palladium-catalyzed reactions of these compounds proceed under mild conditions giving high yields of cross-coupling products.     

Synthesis of N-vinyl derivatives of 2-methyl- and 4(5)-methylimidazoles

Conclusions The reaction of 2-methyl and 4(5)-methylimidazoles with acetylene in the presence of Gu₂Cl₂ leads to the corresponding N-vinyl derivatives. 1-Vinyl-4(5)-methylimidazole is formed as a mixture of two isomers differing in the position of the methyl group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2122–2124, September, 1987.     

Synthesis and biological activity of novel 2-methyl-4-trifluoromethyl-thiazole-5-carboxamide derivatives

Nine novel 2-methyl-4-trifluoromethylthiazole-5-carboxamide derivatives were designed and synthesized utilizing ethyl 4,4,4-trifluoroacetoacetate as a starting material. Subsequently, the biological activity of the compounds was evaluated in the greenhouse. Results indicated that all of the compounds have some fungicidal and insecticidal activity but no herbicidal activity. Compound 1 has fungicidal activity with 90% control of tomato late blight at 375 g ai/ha, while two compounds 2F and 2H show insecticidal activity with 80 and 100% control, respectively, against potato leafhopper at 600 g ai/ha.     

Formation of new base pairs between inosine and 5-methyl-2-thiocytidine derivatives

In this paper, we report DNA and 2'-OMe-RNA probes containing 5-methyl-2-thiocytidine (m(5)s(2)C) residues that can bind selectively and strongly to the corresponding RNA targets containing inosine residues by the significant stacking effect and steric hindrance of the 2-thiocarbonyl group.     

Synthesis and properties of enamine derivatives of 1-methyl-2-phenyl-5-pyrrolone and 5-thiopyrrolone

The corresponding dimethylaminomethylene derivative, from which a number of similar compounds were synthesized by reaction with amines, was obtained by the reaction of 1-methyl-2-phenyl-2-hydroxy-5-oxotetrahydropyrrole with dimethylformamide in the presence of phosphorous oxychloride. The formyl derivatives of 1-methyl-2-phenyl-5-pyrrolone and 5-thiopyrrolone were obtained, and the UV and IR spectra of the enamines of these compounds were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 791–793, June, 1972.     

Vinylhydroquinone. IV. Preparation and polymerization behavior of 2-methyl-5-vinylhydroquinone derivatives

As in the case of vinylhydroquinone (I), its alkyl-substituted derivative, 2-methyl-5-vinylhydroquinone (II) was found to copolymerize with methyl methacrylate by tri-n-butylborane in cyclohexanone at 30°C. II was prepared from the O,O′-bisether compound, 2-methyl-5-vinyl-O,O′-bis(1′-ethoxyethyl)hydroquinone (III). The monomer reactivity ratios (M₂ = II) were determined to be r₁ = 0.37 and r₂ = 0. No homopolymerization proceeded under the same conditions. Ordinary free-radical initiators, such as azobisisobutyronitrile and benzoyl peroxide, were not effective in the homopolymerization of II. 1:1 Copolymers were obtained from II and maleic anhydride by using tri-n-butylborane as an initiator. The copolymers exhibited no definite melting range and decomposed at 370–375°C endothermally (DSC). The polymerization behavior of III was also investigated. Although tri-n-butylborane did not initiate the homopolymerization of the monomer, azobisisobutyronitrile was capable of initiating the homopolymerization and copolymerization of III. The monomer reactivity ratios (M₁ = styrene) were determined to be r₁ = 0.83 and r₂ = 0.18. The ratios gave the following Q and e values; Q = 0.15 and e = ?2.2.     

Dichloro bis(η5) molybdenum catalysed reduction of organic halides by sodium borohydride

Summary Dichloro bis(⁵) molybdenum catalyses the reduction of organic halides by sodium borohydride smoothly and selectively. The reactions with representative organic monohalides and polyhalides are investigated. The ease of reduction depends on the structure of the halide and the solvent used. alkoxycarbonyl and cyano groups are unattacked in the reaction. An oxidative addition-reductive elimination mechanism is tentatively suggested.     

The interaction of poly- and oligosaccharides based on arabinogalactan with 5-aminosalicylic acid

The interaction of high-and low-molecular-weight arabinogalactans with 5-aminosalicylic acid was studied by spectral methods. It was found that the reaction of biopolymers with 5-aminosalicylic acid gave polymeric complex compounds of a 1 : 1 composition. The spectrophotometric data were used to calculate the stability constants of polysaccharide-pharmacon complexes. The influence of the structure of the reagents on their complex formation ability in aqueous solution is analyzed.     

A novel copper-catalyzed,one-pot synthesis of symmetric organic disulfides from alkyl and aryl halides: potassium 5-methyl-1,3,4-oxadiazole-2-thiolate as a novel sulfur transfer reagent

A new method is reported for the synthesis of symmetric diaryl and dialkyl disulfides from aryl and alkyl halides in the presence of copper using potassium 5-methyl-1,3,4-oxadiazole-2-thiolate as the base, ligand, and sulfur-transfer reagent.     

Synthesis of new functional derivatives of pyrazolidine from 1-acetyl-3-methyl-5-nitromethyl-2-phenylpyrazolidine

3-Nitromethylpyrazolidine reacts with derivatives of unsaturated acids and reducing agents with the formation of polyfunctional compounds of the pyrazolidine nucleus. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1365–1369, September, 2006.     

Synthesis of 2-aryl-6-methyl-5-nitroquinoline derivatives as potential prodrug systems for reductive activation

A range of novel 2-aryl-5-nitroquinolines have been synthesised as potential prodrug systems for bioreductive activation. Thus 5-nitroquinoline underwent vicarious nucleophilic substitution at C-6 with bromoform anion to give, after hydrolysis and reduction, the quinoline-6-methanol. Introduction of chlorine at C-2 was followed by palladium-catalysed Suzuki coupling to install the 2-aryl substituent. A fluorescent model ‘drug’, 7-hydroxy-4-methylcoumarin was coupled to the 6-hydroxymethyl group, and its fragmentation upon reduction of the nitro group was investigated.