Diastereoselective Cyclopropanation Utilizing a New Chiral N,O-Acetals Prepared by Electrochemical Oxidation of Carbamates

A new chiral bicyclic tetrahydropyridine derivative was synthesized from L -lysine derivatives utilizing electrochemical oxidation as a key step. Allyl alcohols were incorporated into the tetrahydropyridine derivative to afford N,O-acetals, and the reaction of the resulting N,O-acetals with a carbenoid, which was generated from Et₂Zn and CH₂l₂, yielded cyclopropanated products in moderate diastereoselectivities.     

Development of the moiré method with special reference to its application to biostereometrics

This paper reviews the development of the moiré method in its technical means and practical application to anthropological and medical studies. Emphasis is placed on references in various fields of human biology.     

Sorption von Wasserdampf an Poly-S-carboxy-methyl-L-cystein und dem Natriumsalz

Ohne Zusammenfassung     

Analysis of the effect of interfacial slippage on the elastic moduli of a particle-filled polymer

An attempt was made to study the effect of interfacial slippage on the filler reinforcement based on the boundary condition that the constituents of a particle-filled composite can slip relative to each other, but no cavities are formed at the interfaces. The elastic field satisfying these conditions is derived using the linear theory of elasticity and the effective elastic moduli of the composite are calculated. The following assumptions are made: (1) Filler particles are spherical, (2) fillers are completely dispersed, and (3) the volume fraction of fillers is sufficiently small that the interaction among fillers may be neglected. The expression for the shear modulus of the composite μ^**, which is derived here, is consistent with the viscosity of a suspension which has been derived by Oldroyd. Experiments who that the increase of Young's modulus by glass beads (GB) is lower in polystyrene (PS) than in epoxy resin (Ep). The reinforcement in Ep-GB systems can be estimated by the well known formula derived assuming perfect adhesion. However, the reinforcement in PS-GB systems is in rather good agreement with the formula derived here assuming interfacial slippage.     

Apparent molal volumes of butylammonium chlorides and sodium butanecarboxylates in dilute aqueous solutions

The densities of dilute aqueous solutions of the isomers of butylammonium chlorides (n-, iso-, sec-, andtert-BuNH₃Cl) and sodium butanecarboxylates (n-, iso-, sec-, andtert-BuCOONa) have been determined at 5, 25, and 45°C using a buoyancy technique. The limiting partial molal volumes \(\bar V^\circ\) and expansibilities of the solutes have been evaluated. The branching of alkyl chain causes larger \(\bar V^\circ\) values for BuNH₃Cl series but smaller values for BuCOONa series. The \(\bar V^\circ\) values of branched isomers have been calculated using the data for volume increment accompanying methyl substitution. Good agreement with the experimental values was obtained. It is suggested that the volumetric behavior of the organic electrolytes studied is governed by the influences of the ionic groups on the hydrophobic hydration. The results have been compared with the data for butanol isomers.     

Enrichment and determination of zinc by high-speed countercurrent chromatography.

The capability of high-speed countercurrent chromatography (HSCCC) has been investigated for enrichment and determination of metal ions at trace levels. Separation of selected divalent metal ions was performed using a small coiled column. A hexane solution of 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHPA) was employed as the stationary phase. Loaded divalent metal ions such as Ni, Co, Cu, and Zn were chromatographically eluted in the order of increasing extractability by passing a mobile phase buffered at a desired pH. Individual metal ions showed good linearity between concentrations and chromatographic peak areas of the absorbance, as detected by postcolumn reaction with 4-(2-pyridylazo)resorcinol (PAR). Metal ions enriched into the stationary phase from a sample solution were separated into individual metal ions. The trace quantity of zinc in natural mineral water was determined by enrichment separation through an HSCCC column.