Esr studies on the reactive character of the radical anions,so−2, so−3 and so−4 in aqueous solution

The reactive characteristics of the oxy anion radicals of sulphur, SO^?₂, SO^?₃ and SO^?₄ were investigated by use of the rapid-mixing flow technique coupled with electron spin resonance (ESR) which can detect the radicals having a lifetime of 5–100 msec. The SO^?₂ reduced the aromatic nitro compounds to the corresponding anion radicals, but did not abstract the hydrogen from the saturated compounds nor add to the unsaturated compounds. The SO^?₃ could add to the compounds having CC bond, but did not abstract the hydrogen from the saturated compounds nor reduce the aromatic nitro compounds. The SO^?₄ could abstract the hydrogen from the saturated compounds and also add to the unsaturated compounds having CC bond, but did not reduce the aromatic nitro compounds. These differences of the reactivity towards the organic substrates were discussed on the basis of the difference in the distribution of the unpaired electron density of each radical anion.     

Enantioselective addition of diethylzinc to benzaldehyde catalyzed by a small amount of chiral 2-amino-1-alcohols

The reaction of diethylzinc with benzaldehyde catalyzed by a small amount of chiral 2-amino-1-alcohols in toluene at room temperature gave optically active 1-phenylpropan-1-ol almost quantitatively in ～, 50% ee.     

Carbon-13 NMR study of substituted benzyl N,N-dimethylcarbamates

The ¹³C NMR chemical shifts of m- and p-substituted benzyl N,N-dimethylcarbamates were measured in CDCl₃. The meta and para ¹³C substituent chemical shifts were analysed by means of dual substituent parameter (DSP) equations. Good correlations were obtained, especially for the para-carbon substituent chemical shifts. The computed transmission coefficients, ρ_I and ρ_R, are consistent with the general features of the fitting parameters. It has been shown that no significant electron demand is imposed by the ? CH₂OCON(CH₃)₂ substituent.     

Reaction of tropone hydrazones with heterocumulenes such as isocyanate,ketene, and sulfene

Tropone benzoyl- and tosylhydrazones underwent the [8+2] cycloaddition reaction with isocyanates to afford the cyclohepta[d]imidazolin-2-one derivatives. This means that these hydrazones behaved as 8-amino-8-azaheptafulvenes. Also, the tropone hydrazones reacted with phenylketene and phenylsulfene in more complicated manners.     

Untersuchung der Verdampfung von Poly?thylen-Oligomeren mittels GPC

Ohne Zusammenfassung     

An upper bound on the length of a Hamiltonian walk of a maximal planar graph

A Hamiltonian walk of a connected graph is a shortest closed walk that passes through every vertex at least once, and the length of a Hamiltonian walk is the total number of edges traversed by the walk. We show that every maximal planar graph with p(≥ 3) vertices has a Hamiltonian cycle or a Hamiltonian walk of length ≤ 3(p - 3)/2.     

Synthesis of functional proteins by mixing peptide motifs

Here, we describe a synthetic approach for generating artificial proteins by the assemblage of naturally occurring peptide motifs. Two motifs respectively related to apoptosis induction and protein transduction were encrypted into different reading frames of an artificial gene (microgene), which was then polymerized; random frame shifts at the junctions between the microgene units yielded combinatorial polymers of three reading frames. Among the proteins created, #284 was found to penetrate through cell membranes and exert a strong apoptotic effect on several cancer cell lines. Because a simple linkage of these motifs was not sufficient to construct a bifunctional peptide, and the successful reconstitution was dependent on how they were joined together, the combinatorial strategy is important for reconstituting functions from mixtures of motifs. This microgene-based approach represents a novel system for creating proteins with desired functions.