Enzymatic synthesis of a soluble polyphenol derivative from 4,4′-biphenyldiol

Enzymatic oxidative polymerization of 4,4′-biphenyldiol was performed in an aqueous organic solvent using horseradish peroxidase as catalyst. In the polymerization using a mixture of 1,4-dioxane and phosphate buffer (pH 7.0) (80:20 vol-%) as solvent, the monomer was quantitatively consumed to give powdery polymeric materials in a high yield. The resulting polymer is soluble in polar solvents such as N,N-dimethylformamide, dimethyl sulfoxide, and acetone. The molecular weight of the methylated product is 7.3 × 10³. The polymer exhibits high thermal stability under nitrogen.     

Enzymatic polymerization to polysaccharides of well-defined structure

Various poly- and oligosaccharides having a well-defined structure have successfully been synthesized via enzymatic polymerization of glycosyl fluoride monomers. All of the reaction proceeded under perfect control of regio- and stereochemistry. The relative direction of the synthetic cellulose (parallel or antiparallel) could be controlled in vitro in the enzyme-promoted propagation system, and based on these findings, a new concept “allos-selectivity” has been proposed.     

Improved resolution for aerial imaging by retro-reflection with two transparent spheres

Optical Review - This paper proposes a method to improve the modulation transfer function (MTF) of aerial images by combining an aerial imaging optical system by retro-reflection with conjugated...     

First Diazosulfonate Homopolymer by Enzymatic Polymerization

The polymerization behavior of phenolic azosulfonates and triazene by means of enzymatic polymerization using horseradish peroxidase was studied. While for the latter one, only oligomerization was observed, sodium 4‐hydroxybenzenediazosulfonate was successfully homopolymerized. The obtained polymer had an average molecular weight of M _n = 3 000 with a polydispersity index of 1.51. This is the first example of a homopolymer bearing an azosulfonate function in every monomer unit.

     

Novel results obtained by freezing berry pseudorotation of phosphoranes (10‐P‐5)

By freezing Berry pseudorotation of spirophosphoranes with recourse to the rigidity of the Martin bidentate ligand, we successfully prepared configurationally stable enantiomeric pairs of optically active phosphoranes, and could isolate “anti‐apicophilic” C‐apical O‐equatorial (O‐cis) phosphoranes. The effect of σ*_{P O} orbital of the O‐cis phosphorane was investigated both experimentally and theoretically. O‐cis phosphoranes were revealed to be much more electrophilic at the phosphorus atom than O‐trans isomers by experimental studies. The acidity of the α‐proton of an O‐cis benzylphosphorane was found to be higher than that of the corresponding O‐trans isomer. By the reaction of the α‐carbanion of an O‐cis benzylphosphorane with PhCHO, we succeeded in the first isolation and full structural characterization of a 12‐P‐6 phosphate bearing an oxaphosphetane ring, the intermediate in the Wittig type reaction using a 10‐P‐5 phosphorane. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:390–396, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10072