Synthesis and electrochemical studies of ferrocene-dithiafulvalenes (Fc-DTF) and 1,1′-bis(dithiafulvalenyl)ferrocene (DTF-Fc-DTF). An approach towards new conducting organic materials

Novel π-conjugated donor compounds based on the strong electron-donating ferrocene moiety and dithiafulvalene donors exhibited increased electron donor ability. The ferrocenylketones 4a,b, 5, 8 and 9 were synthesized via described methods, and allowed to react with 2-dimethoxyphosphinyl-1,3-benzodithiole (13) in the presence of n-BuLi at −78°C in dry THF to afford the corresponding ferrocene-dithiafulvalenes 14a,b, 18, 19 and 1,1′-bis(benzo-1,3-dithiol-2-ylidene)ethyl]ferrocene (15). Electrochemical properties of these new donor compounds were studied using cyclic voltammetry (CV) and UV-Vis spectra. CV and absorption spectra of the new compounds were studied in comparison with ferrocene (6) and dibenzo-tetrathiafulvalene DB-TTF 3. Two-electron and three-electron redox behaviors were observed as two waves. The absorption spectra showed a red-shift with a slight increase in the absorption intensities.     

Enzymatic resolution of 4-methyl-, 4-phenyl- and 6-phenyltetrahydro-2H-pyran-2-one using esterases

Enantioselective hydrolysis of racemic tetrahydro-2H-pyran-2-ones (δ-valerolactones) using esterase resulted in the formation of optically active (R)-4-methyl-, (R)-4-phenyl- or (R)-6-phenyltetrahydro-2H-pyran-2-ones and the corresponding (S)-8-hydroxypentanoic acid derivatives.     

Effect of reaction medium on copolymerization of acrylonitrile and methyl acrylate

The copolymerization of acrylonitrile (AN) with methyl acrylate (MEA) has been investigated in three types of polymerization, i.e., emulsion polymerization in water with a water-soluble initiator, suspension polymerization in water with an oil-soluble and water-insoluble initiator, and solution polymerization in dimethyl sulfoxide (DMSO). Monomer reactivity ratios at 50°C. for AN and MEA are found to be r₁ = 0.78 ± 0.02, r₂ = 1.04 ± 0.02 in emulsion polymerization; r₁ = 1.02 ± 0.02, r₂ = 0.70 ± 0.02 in DMSO solution polymerization; r₁ = 0.75 ± 0.05, r₂ = 1.54 ± 0.05 in suspension polymerization. The large differences found in the reactivity ratios may be attributed to the different ratio of concentration of two monomers in the loci of polymerization. Chemically, AN is somewhat more reactive than MEA as shown by the reactivity ratios in DMSO. In the case of the suspension polymerization, the MEA/AN ratio in the polymer particles in which polymerization occurs may be higher than that in the total phase. Experimental results of the emulsion polymerization show that the emulsion polymerization of AN occurs both in the particles and in water. In addition, rates of the copolymerization of AN with MEA have also been investigated.     

Protein binding of quinolonecarboxylic acids. I. Cinoxacin, nalidixic acid and pipemidic acid

Binding of cinoxain (CINX), nalidixic acid (NA) and pipemidic acid (PPA) to serum proteins was investigated by equilibrium dialysis, ultrafiltration and circular dichroism (CD) spectroscopy. CINX and NA were found to bind mainly to albumin in human serum, the latter interacting with the protein about ten times as strongly as CINX at pH 7.4 and 37 degrees C. PPA showed little or no significant binding to human serum albumin (HSA), alpha 1-acid glycoprotein, and globulins, but showed 20-30% binding to protein in human serum. The CD results were suggestive of some weak interaction of PPA with human apotransferrin. Binding of the three drugs to HSA was found to depend on the lipophilicity of their substituents at the 7-position. The degree of protein binding for human, dog and rat sera at 37 degrees C was in the order of NA (92-97%) greater than CINX (68-90%) greater than PPA (20-30%) at drug concentrations of 10-30 micrograms/ml. CINX showed relatively large species dependence in serum protein binding, which seemed to be due to different affinities of this drug to the respective albumins. CINX was found to bind to rat serum albumin as strongly as NA.     

Enzymatic resolution of trans-2,3-dihydro-3-hydroxy-2-phenyl-4H-1-benzopyran-4-one (trans-flavanon-3-ol) by lipase

trans-2,3-Dihydro-3-hydroxy-2-phenyl-4H-l-benzopyran-4-one (trans-flavanon-3-ol) was resolved to acetate of (2S,3S)-(-)-trans-flavanon-3-ol and (2R,3R)-(-)-trans-flavanon-3-ol by an enzymatic transesterification with vinyl acetate in the presence of Pseudomonas cepacia lipase.     

Hydrothermal Synthesis and Characterization of Nb3O7(OH)

Triniobium hydroxide heptaoxide, Nb₃O₇(OH), was prepared hydrothermally by treating niobic acid or triniobium chloride heptaoxide with 3.0 mol/dm³ sulfuric acid at 250–350°C and 15 MPa. The hydroxide oxide was isomorphous with the low-pressure form of triniobium fluoride heptaoxide which is built up of 3 X ∞ blocks of the ReO₃ structure with crystallographic shear in one dimension. When heated in air, Nb₃O₇(OH) dehydrated up to 460°C to give poorly crystallized Nb₂O₅, which, on further heating, changed slowly into a less ordered precursor of M? Nb₂O₅(¹). Hydrothermal treatment of Nb₃O₇(OH) with pure water at 400–500°C afforded P? and R? Nb₂O₅; the conversion of Nb₃O₇(OH) is explained in terms of the close structural relation among these three forms.     

Alternating copolymerization of propylene oxide and carbon dioxide with an alumina supported diethylzinc catalyst

Diethylzinc was allowed to react with γ-alumina in n-heptane at 50°C, and the copolymerization of propylene oxide and carbon dioxide was investigated in some detail at 30–90°C by using the reaction product as a catalyst. From an analysis of the catalyst it was found that diethylzinc reacted with the surface hydroxyl groups of γ-alumina mainly to give the following A-type species by evolving ethane: The catalyst showed considerably high activity for the copolymerization. The polymer obtained was a white solid with a high molecular weight soluble in benzene, acetone, dioxane, and methylene chloride and insoluble in diethyl ether and water. It was confirmed as an alternate copolymer of propylene oxide and carbon dioxide. The copolymerization was also conducted with a reaction mixture of the catalyst and catechol in which the molar ratio of catechol to the A-type species was varied. The copolymerization activity decreased linearly with an increase in the molar ratio and disappeared completely at the molar ratio of unity. On the basis of these results it has been concluded that the A-type is the true active species for the copolymerization.