A New Convenient Synthesis of α-Arylpropionic Acid Esters and α-Arylpropionitriles

Various types of α-arylpropionic acid esters were effectively obtained by the coupling reaction of aryl Grignard reagents and α-bromopropionic acid esters in the presence of nickel catalysts. α-Arylpropionitriles, precursors of α-arylpropionic acids, were also synthesized by the reaction of α-methanesulfonyloxypropionitrile and arylcopper reagents prepared from equimolar amount of arylmagnesium halides and copper(I) bromide.     

Synthetic Approach Toward the Partial Sequences of Betaglycan in the Linkage Region on Solid Support and in Solution Phase

We have synthesized, for the first time, the partial sequence of the betaglycan composed of the tetraosyl hexapeptide, which was directly usable as a probe for enzymatic glycosyl transfer. Stepwise elongation afforded the corresponding tetraosyl trichloroacetimidate. The common glycosyl dipeptide:[β‐d‐GlcA‐(1→3)‐β‐d‐Gal‐(1→3)‐β‐d‐Gal‐(1→4)‐β‐d‐Xyl‐(1→O)‐Ser‐Gly] was synthesized by glycosylation of the corresponding tetraosyl trichloroacetimidate and Ser‐Gly moiety. The glycosyl dipeptide was coupled with other core peptide parts in solution phase and on a solid support. These glycosyl hexapeptides were then transformed into the desired target compounds.     

Synthesis and structural,electrochemical, and optical properties of Ru(II) complexes with azobis(2,2'-bipyridine)s

Two new ditopic ligands, 5,5"-azobis(2,2'-bipyridine) (5,5"-azo) and 5,5"-azoxybis(2,2'-bipyridine) (5,5"-azoxy), were prepared by the reduction of nitro precursors. Mononuclear and dinuclear Ru(II) complexes having one of these bridging ligands and 2,2'-bipyridine terminal ligands were also prepared, and their properties were compared with previously reported Ru(II) complexes having 4,4"-azobis(2,2'-bipyridine) (4,4"-azo). The X-ray crystal structure showed that 5,5"-azo adopts the trans conformation and a planar rodlike shape. The X-ray crystal structure of [(bpy)(2)Ru(5,5"-azo)Ru(bpy)(2)](PF(6))(4) (Ru(5,5"-azo)Ru) showed that the bridging ligand is in the trans conformation and nearly planar also in the complex and the metal-to-metal distance is 10.0 A. The azo or azoxy ligand in these complexes exhibits reduction processes at less negative potentials than the terminal bpy's due to the low-lying pi level. The electronic absorption spectra for the complexes having 5,5"-azo or 5,5"-azoxy exhibit an extended low-energy metal-to-ligand charge-transfer absorption. The ligands, 5,5"-azo and 5,5"-azoxy, and the mononuclear complex, [(bpy)(2)Ru(5,5"-azo)](2+), isomerize reversibly upon light irradiation. The low-energy MLCT state sensitizes the isomerization of the azo moiety in this complex. While [(bpy)(2)Ru(4,4"-azo)Ru(bpy)(2)](PF(6))(4) exhibits light switch properties, namely, significant electrochromism and a large luminescence enhancement, upon reduction, Ru(5,5"-azo)Ru does not show these properties. The radical anion formation upon reduction of these complexes has been confirmed by ESR spectroscopy.     

Synthesis and Odor Evaluation of Stereoisomers of Imine Derivatives in Roasted Spotted Shrimp

All possible stereoisomers of imine derivatives 1 – 4 , which have the characteristic roast odor of seafood, were synthesized. As a result of odor evaluation of all isomers, we found that each isomer has a different and characteristic odor of roasted seafood.     

Enantiomeric separation of dansylamino acids by capillary zone electrophoresis based on complexation with cyclodextrins

Summary The enantiomeric separation ability of unmodified and methylated cyclodextrins (CDs) during capillary zone electrophoresis (CZE) was investigated using twelve dansylamino acids. Unmodified - and -CDs exhibited high enantioselectivities. -CD could scarcely separate the enantiomers before and after dimethylation, but obtained enantioselectivity after trimethylation. On the other hand, dimethylation of -CD removed much of its high enantioselectivity. Moreover, the chemical modifications produced a reverse in the migration order of the enantiomers. The inclusion of dansyl-DL-phenylalanine with CDs was evaluated using 600 MHz ¹H NMR spectroscopy.     

Separation and purification of 99mTc from 99Mo produced by electron linear accelerator

The medical radionuclide ⁹⁹Mo was produced by the ¹⁰⁰Mo(γ,n) reaction using bremsstrahlung photons generated by an electron linear accelerator. The amount of ⁹⁹Mo produced was compared to that predicted by calculation using the particles and heavy ion transport code system. From the ⁹⁹Mo produced, highly pure ^99mTc was separated using the so-called technetium master milker, and the chemical yield of ^99mTc was 83–99 %. The installation of a new complex using this method and the electron linear accelerator with the preferable specification was suggested, and a possibility to supply the demand of ^99mTc was discussed and shown.

     

Selective separation of water–ethanol mixture through synthetic polymer membranes having carboxylic acid as a functional group

Separation of water–ethanol mixture through a membrane was carried out by pervaporation using a membrane which provided a hydrogen-bonding interaction. A membrane obtained from poly(acrylic acid-co-acrylonitrile) was effective for a selective separation of water from aqueous ethanol solution by pervaporation technique. Spectroscopic and flux analyses verified that this high selectivity toward water was attributed to the hydrogen-bonding interaction between water and acrylic acid (carboxylic acid) unit in the membrane. On the other hand, a membrane from poly(acrylic acid-co-styrene) preferentially permeated ethanol in the low water feed concentration region.     

Medicinal flowers. I. Aldose reductase inhibitors and three new eudesmane-type sesquiterpenes, kikkanols A, B, and C, from the flowers of Chrysanthemum indicum L

The methanolic extract from the flowers of Chrysanthemum indicum L., Chrysanthemi Indici Flos, was found to show inhibitory activity against rat lens aldose reductase. By bioassay-guided separation, the active components, such as flavone and flavone glycosides, were isolated from the extract together with three new eudesmane-type sesquiterpenes, kikkanols A, B, and C. The structures of kikkanols A, B, and C were elucidated on the basis of chemical and physicochemical evidence, which included application of the modified Mosher's method.