Synthesis of (Aza)n[3n]cyclophanes as host molecules

(Aza)_n[3ⁿ]cyclophanes were synthesized by the coupling reaction of p-toluenesulfonamide and bis(halomethyl) derivatives in the presence of a base (K₂CO₃, NaH etc.) using DMF, dioxane etc. as a solvent, in acceptable yields. Tetraaza macrocyclic compound (the dimer in Fig. 1) obtained by the coupling of 2,11-diaza[3.3]metacyclophane with 1,3-bis(bromomethyl)benzene gavea 1:1 adduct with benzene.Presented partly at the 42nd Autumn Annual Meeting of the Chemical Society of Japan, Sendai, September, 1980; Abstr. No. 1J17.     

Radioactivity distribution measurement of various natural material surfaces with Imaging Plate

Distribution images of natural radioactivity in natural materials such as vegetables were obtained by using Imaging Plate. In such cases, it is necessary to reduce background radiation intensity by one order or more. Graded shielding is very important. Especially, the innermost surface of a shielding box should be covered with acrylic resin plate. We obtained natural radioactivity distribution images of vegetables, sea food, meat etc. Mostly -rays emitted from⁴⁰K print the radioactivity distribution image. Comparison between -ray intensity of KCl solution measured with HPGe detector and that of natural material specimen gave the radioactivity around 0.060.4 Bq/g depending on the kind and the part of specimens.     

Synthesis and evaluation of iodinated benzamide derivatives as selective and reversible monoamine oxidase B inhibitors.

A new series of iodinated analogues of N-(2-aminoethyl)benzamide was synthesized and evaluated for inhibitory potency and specificity toward monoamine oxidase type-B (MAO-B). Among them, N-(2-aminoethyl)-2-chloro-4-iodobenzamide hydrochloride (2d) showed high inhibitory potency and selectivity against MAO-B. The type of MAO-B inhibition by 2d was non-competitive and the inhibition constant (Ki) was 0.80 microM. Strong and selective in vivo MAO-B inhibition by 2d was also confirmed. The brain MAO-B inhibition by 2d was reversible and the enzyme activity completely returned to the control value 24 h after administration. Compound 2d was, therefore, considered to be a candidate for advanced development as a radioiodinated ligand that may be useful for functional MAO-B studies in the living brain using single photon emission computer tomography.     

Synthesis of iron—cobalt ultrafine particles by decomposition of Fe(CO)5---Co(CO)3NO using a TEA CO2 laser

Ultrafine particles of iron—cobalt alloy were synthesized and isolated at room temperature in a maximum yield of 90% by the dielectric breakdown of a mixture of Fe(CO)₅ (5 Torr) and Co(CO)₃NO (0.5 Torr) on irradiation with a tightly-focused laser beam of a transversely-excited-atmospheric (TEA) CO₂ laser. CO and NO are also obtained as volatile products. Transmission electron micrographs of the iron-cobalt particles show the existence of fine and well-organized spherical particles. The distribution of the particle size is relatively uniform in the range 6–9 nm with a mean particle size of 8 nm. In X-ray diffractometry, the ultrafine particles are found to be mainly f.c.c. γ-iron—cobalt alloy which is normally stable in the range 1183–1234 K to 1673–1773 K. The b.c.c. -iron—cobalt, iron oxides and cobalt oxides are observed as minor products (γ-iron—cobalt to iron---cobalt OXIDES=8:1:1). The ratio of iron and cobalt atoms in the particles can be changed by changing the mixture of Fe(CO)₅ and Co(CO)₃NO. The ratio of γ-iron—cobalt to -iron—cobalt to iron—cobalt oxide also depends on the ratio of iron and cobalt atoms in the particles.     

Electrooxidative glycosylation through C-S bond cleavage of 1-arylthio-2,3-dideoxyglycosides. Synthesis of 2',3'-dideoxynucleosides

[reaction: see text] The electrooxidative glycosylation of newly designed 1-arylthio-substituted 2,3-dideoxyglycosides is described. The halide salt-mediated electrooxidation utilizing either of the alpha- or beta-thiodideoxyglycosides proceeded smoothly at -78 degrees C to give dideoxynucleosides in a beta-selective manner, presumably through a 1-halo-substituted glycosyl donor.     

Superoxide ion formation process on reduced MoO3---TiO2

Two novel Mo⁵⁺ ions, different from either the D_2d symmetry Mo⁵⁺ on anatase or the D_2hMo⁵⁺ on rutile, appeared on partially reduced molybdenum oxide supported on -titanic acid. The oxygen molecule is held on one of these novel Mo⁵⁺ ions but is not reduced to the superoxide ion. Oxygen is reduced to O⁻₂ entirely by the Mo⁴⁺ ion formed from the D_2d symmetry ion and the O⁻₂ is subsequently stabilized after moving to a Ti⁴⁺-site.