Isolation of keto-s-phenylthioxime of [23]cyclophane-1,2-dione. Re-visited contraction of 1,2,5-thiadiazole ring incorporated in a [23]cyclophane bridge by phenylmagnesium bromide

[2³]Paracyclophane derivative 3 of keto-S-phenylthioxime which is the hydrolyzed product of the hypothetical intermediate in the reaction of 1,2,5-thiadiazole with organometallic reagents, was obtained, together with diketone 1 , in the reaction of 1,2,5-thiadiazolo[2³]paracyclophane 2 with two equivalents of phenylmagnesium bromide. Contrary, [2³]metacyclophane 7 gave only diketone 12 in the reaction with phenylmagnesium bromide under the same conditions.     

Carbon Nanosheets by Morphology‐Retained Carbonization of Two‐Dimensional Assembled Anisotropic Carbon Nanorings

Two‐dimensional (2D) carbon nanomaterials possessing promising physical and chemical properties find applications in high‐performance energy storage devices and catalysts. However, large‐scale fabrication of 2D carbon nanostructures is based on a few specific carbon templates or precursors and poses a formidable challenge. Now a new bottom‐up method for carbon nanosheet fabrication using a newly designed anisotropic carbon nanoring molecule, CPPhen, is presented. CPPhen was self‐assembled at a dynamic air–water interface with a vortex motion to afford molecular nanosheets, which were then carbonized under inert gas flow. Their nanosheet morphologies were retained after carbonization, which has never been seen for low‐molecular weight compounds. Furthermore, adding pyridine as a nitrogen dopant in the self‐assembly step successfully afforded nitrogen‐doped carbon nanosheets containing mainly pyridinic nitrogen species.     

Biomimetic Reductive Amination of Fluoro Aldehydes and Ketones via [1,3]-Proton Shift Reaction.(1) Scope and Limitations

A systematic study of azomethine-azomethine isomerizations of the N-benzylimines 2, derived from fluorinated aldehydes or ketones and benzylamine, has been made. The results reveal that, in sharp contrast to hydrocarbon analogs, fluorinated imines of 2 in triethylamine solution undergo isomerizations to give the corresponding N-benzylidene derivatives 5 (for 5/2 K > 32) in good isolated yields. The rates of the isomerizations depend on the starting imine structures and increase in the following order: aryl perfluoroalkyl ketimine 2m, per(poly)fluoroalkyl aldimine 2a,d-g, perfluoroaryl aldimine 2h, alkyl perfluoroalkyl ketimine 2i,j. The presence of chlorine or bromine atoms in the alpha-position to the C=N double bond of the starting imine favors a dehydrohalogenation reaction, giving rise to unsaturated products 6-9. The azomethine-azomethine isomerization was studied and proven to proceed essentially (>98%) intramolecularly with isotope exchange experiments. High chemical yields, the simplicity of the experimental procedure, and the low cost of all reagents employed make this biomimetic transamination of fluorocarbonyl compounds a practical method for preparing fluorine-containing amines of biological interest.     

How and why 41S-2 antibody subunits acquire the ability to catalyze decomposition of the conserved sequence of gp41 of HIV-1

It has become well known that antibodies obtained by immunization with the ground state of peptides can display proteolytic activity. Our antibody light chain produced by immunization with the peptide RGPDRPEGIEEEGGERDRD, a highly conserved sequence in envelope gp41 of HIV-1 showed the ability to cleave this peptide. Moreover, its heavy chain also decomposed the peptide, although this occurred at lower activity levels compared with the light chain, while the whole antibody did not show any catalytic activity. From molecular modeling, the light and heavy chains of the antibody were deduced to possess catalytic triads (Asp, His, and Ser) in their steric conformations, which may be responsible for the observed proteolytic activity.     

Functional monomers and polymers. XCIV. Photochemical reactions on the synthetic polymers containing thymine bases in the presence of adenine derivatives

Photodimerization reactions of polyacrylate and polymethacrylate derivatives and the dimer model compound containing thymine bases were studied in the presence of adenine derivatives in dimethyl sulfoxide; N,N-dimethylformamide; and dimethyl sulfoxide–ethylene glycol solutions. The photodimerization of thymine bases both in the polymers and in the dimer model compound was found to be quenched by the addition of adenine derivatives. Base-base interaction in the ground state was also studied by ultraviolet (UV) spectroscopy in the three solvents. The quenching of the photodimerizationof thymine bases in the presence of adenine derivatives was discussed in terms of the specific interaction between adenine and thymine bases both in ground and excited states.     

Characteristics of VHF H2 Plasma Produced at High Pressure

A VHF H₂ plasma was produced with the multi rod electrode at high pressure and the plasma parameters were measured as a function of pressure for different VHF powers at 60 MHz. It was found that when the pressure is increased, the ion saturation current peaks at certain pressure and finally decreases at high pressures, while the electron temperature is around 10 eV. The wall potential at high pressure was lower than the values estimated from the electron temperature using the probe theory. Furthermore, the anomalous reduction of the electron saturation current was observed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Inhibitory Effects of Hydrogels on the Adhesion,Germination, and Development of Zoospores Originating from Laminaria angustata

The inhibition of germination and development of zoospores originating from Laminaria angustata originated on various kinds of hydrogels is studied. The effects of the water content of the gel (the degree of swelling), the electrical nature (neutral, positive charge, negative charge), the charge density, the counterions of hydrogels on the inhibition of zoospore germination and development of gametophytes are phenomenologically investigated. Among the gels investigated, poly(acrylic acid) (PAA) gel showed a dramatic inhibition to germination, and might serve as a novel, environmentally safe inhibitor of zoospore adhesion.     

Development and application of a latent hydrosilylation catalyst. IX. Control of the catalytic activity of a platinum catalyst by polymers bearing amine moieties

A new thermal‐latent hydrosilylation catalyst consisting of H₂PtCl₆ and polymers bearing amine moieties is described. In the presence of aminated polymers, the catalytic activity of H₂PtCl₆ was suppressed remarkably in the model reaction of triethylsilane with trimethylvinylsilane, whose effect was remarkably higher in comparison with monomeric amines. On heating, however, sufficient catalytic activity was attained where the activation temperature was dependent on the amine content in the polymer and polymer structure. Furthermore, this catalyst system was applied to the curing process of silicone resin to confirm the thermal‐latent character of the catalyst. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 804–809, 2000