Yoko Nambu

A novel reaction for the functionalization of epoxy resins: New regio- and chemoselective ring-opening of epoxides with aryl silyl ether catalyzed by cesium fluoride

Abstract By use of cesium fluoride as a catalyst, aryl or alkyl glycidyl ethers were ring-opened by aryl trimethylsilyl ether to produce O-protected aryloxyhydrins with a quantitative regioselectivity for the first time. Alkyl silyl ether was ineffective for this ring-opening.

A new electron mediator: reduction by Na2S2O4 in organic media of a novel viologen functionalized with crown ether structure

Synthesis of a novel viologen functionalized with two 15-crown-5 units, and its reduction by sodium dithionite in organic media, were conducted; the viologen is efficiently reduced to its monomeric cation radical owing to the solubilisation of sodium dithionite in the organic solvent by the 15-crown-5 moiety.

Selective formation of polymer-bound monomeric and dimeric viologen cation radicals by choice of pendant group linkage

A monomeric viologen cation radical or its dimer are selectively obtained from a homo- or a co-polymer of a new viologen monomer, vinyl viologen.

Substituted polymethylglutamate membrane for immobilization of urease

Abstract Poly-γ-methyl- l -glutamate (PMG) was modified and used for enzyme immobilization. Trichloroethyl ester (TCE) and three kinds of amino groups (ethylenediamine, ED; 1,8-diamino-4-amino-methyloctane, TA; polyethyleneimine, PEI) were introduced into the pendant group of PMG. A membrane was prepared from these polymers for enzyme immobilization. Urease was immobilized on each membrane using glutaraldehyde or water-soluble carbodiimide. Urease was very stable when it was immobilized with water-soluble carbodiimide on the membrane having PEI in the pendant group. The characteristics of immobilized urease were also discussed.