Stereocontrolled synthesis of a potent antimalarial alkaloid, (+)-febrifugine

A novel and stereocontrolled synthetic path to a potential antimalarial piperidine alkaloid, (+)-febrifugine, was established by employing the reductive deamination and simultaneous recyclization of a proline derivative with samarium diiodide, as a key step.     

Volume Contents

Statistical Inference for Stochastic Processes -     

A new semiconducting organic-inorganic nanocomposite, 1,5-diaminonphthalene-saponite intercalation compound

We synthesized a new intercalation compound, 1,5-diaminonaphathalene(DAN)-saponite where intercalated DAN molecules were shown to have a formal charge of +0.67 The measurement of optical diffuse reflectance spectra revealed the formation of electronic bands with a gap of ca. 1 eV suggesting semiconducting behaviour of this system. From ESR measurements, the radical formation in DAN-saponite was confirmed and the spin concentration was determined to be 1 spin per 200 and 300 DAN-molecules at 290 and 7.9 K, respectively. This temperature dependence of the spin density also implies the semiconductive nature of DAN-saponite.     

Magnetism in electron-doped copper oxides

We report muon spin relaxation/rotation measurements on sintered powder samples of Nd_2−x Ce _x CuO_4−y and a large single crystal of Nd₂CuO_4−y . We find an electronic phase diagram which is quite similar to that of hole-doped superconductors such as La_2−x Sr _x CuO_4−y , although the doping of electrons into the system is less efficient in destroying the static moments on the copper spins. Static magnetic order in Nd₂CuO_4−y appears below about 250 K, and two spin reorientations are seen atT=75 K andT=35 K. Measurements of the magnetic field penetration depth have been unsuccessful due to the rare-earth paramagnetism of these materials.     

Local units and Gauss sums

In this paper, we will determine the structure of a certain module which is related to the plus part of the ideal class groups in terms of the divisibility of Gauss sums in some local fields. This result is a generalization of a result of Iwasawa and the previous work of Ichimura and Hachimori.     

Adsorption of fission products onto soils using a fission multitracer

The adsorption behavior of fission products to various soils was studied using a multitracer. The multitracer was prepared by neutron irradiation of ²³⁵U. Distribution coefficients of fission products were obtained for seventeen kinds of Japanese soils. It was found that zirconium, niobium, and rare earth elements show high distribution coefficients for all soil samples, however, elements like alkali metals show varied values.