Preparation and some spectral properties of benzo-fused 1,4-dimethyl-2(1H)-quinolinones

The preparation of the angular and linear isomers of benzo-fused 1,4-dimethyl-2(1H)-quinolinones 3a–5a and their spectral data including ¹³C-nmr data are reported. Structural difference among 3a–5a is confirmed from the proximity effect in ¹H- and ¹³C-nmr data and from the uv spectral pattern.     

Biochemical, molecular genetic, and structural analyses of the staphylococcal nucleoid.

The nucleoid structure of an important human pathogen, Staphylococcus aureus, was dissected by atomic force microscopy (AFM). The nucleoids dispersed on a cover glass consisted of fibrous units with two different widths of 40 and 80 nm, a feature shared with those of Escherichia coli. On the other hand, cells exposed to an oxidative stress exhibited clogged nucleoids. A knock-out of mrgA (metallo regulated genes A) encoding a staphylococcal homolog of the nucleoid compaction factor (E. coli Dps) eliminated the compaction response to the oxidative stress and reduced the susceptibilities to H2O2 and UV irradiation. We also observed that the negative supercoiling of plasmids is increased by the oxidative stress. A possible interrelation between the helical density and the nucleoid compaction is discussed in relation to the oxidative stress response.     

Laser isotope separation of 13C by an elimination method

An elimination method is presented for laser isotope separation. It consists of flow cycles of feed molecules, in which an isotope component of non-interest, instead of the one of interest, is photolyzed to be eliminated, and the residue is recycled for photlysis. An isotope can be enriched as much as desired even if the isotope selectivity in the photolysis is low. The separation of ¹³C is demonstrated by employing multiphoton dissociation using a TEA CO₂ laser.     

Synthesis and evaluation of alpha-fucosidase inhibitory activity of 5a-carba-alpha-L-fucopyranose and alpha-DL-fucopyranosylamine

5a-Carba-alpha-L-fucopyranose and -alpha-DL-fucopyranosylamine were synthesized in conventional manner starting from 2,3,4-tri-O-acetyl-6-bromo-6-deoxy-5a-carba-beta-D- and -DL-glucopyranosyl bromides, respectively, and assayed for inhibitory activity against alpha-fucosidase (bovine kidney). Although the former proved to be only a moderate inhibitor (Ki = 4.3 x 10(-5) M), the latter could be shown to possess strong inhibitory potential (Ki = 2.3 x 10(-7) M). Diastereoisomeric imino-linked 5a'-carbadisaccharides were synthesized by coupling of the racemic 5a-carba-alpha-fucopyranosylamine and 1,6:3,4-dianhydro-2-azido-2-deoxy-beta-D-galactopyranose, in order to estimate approximately the inhibitory activity of individual optical antipodes of 5a-carba-alpha-fucopyranosylamine.     

Synthesis of dl-coriolin

The total synthesis of dl-coriolin has been achieved in a stereoselective way. The key tricyclic intermediate was synthesized from dicyclopentadiene through a route which involved an S_N2 reaction at a neopentylic position.     

Synthesis and metal binding properties of novel sulfur-containing functional oligomer

The synthesis and metal ion binding properties of a new class of functional oligomers are described. Oligo[1-(N-phenylthiocarbamoyl)aziridine] (DP ca. 8) and its analogs are prepared by ring-opening oligomerization of the corresponding aziridine monomers in good yields. These oligomers contain sulfur groups capable of binding “soft” metal ions, and the selective binding properties of the novel oligomer for Cu(II) and Hg(II) ions are investigated by liquid-solid adsorption and liquid-liquid extraction experiments.     

A convenient and one-pot synthesis of 9-substituted carbazoles from primary amine hydrochlorides and 2,5-dimethoxytetrahydrofuran

Carbazoles are the very important compounds in material science, nevertheless conventional syntheses required severe and complicated reaction conditions. In the process of preparation of pyrrole derivatives, we found that a primary amine hydrochloride 1 and 2,5-dimethoxytetrahydrofuran 2 were refluxed in a benzenewater (100:4 (v/v)) mixture to be obtained 9-substituted carbazole 5 in a high yield. This method is the one-pot synthesis of 9-substituted carbazoles 5 under mild and convenient conditions.