Classification of non‐well‐founded sets and an application

A complete list of Finsler, Scott and Boffa sets whose transitive closures contain 1, 2 and 3 elements is given. An algorithm for deciding the identity of hereditarily finite Scott sets is presented. Anti‐well‐founded (awf) sets, i. e., non‐well‐founded sets whose all maximal ∈‐paths are circular, are studied. For example they form transitive inner models of ZFC minus foundation and empty set, and they include uncountably many hereditarily finite awf sets. A complete list of Finsler and Boffa awf sets with 2 and 3 elements in their transitive closure is given. Next the existence of infinite descending ∈‐sequences in Aczel universes is shown. Finally a theorem of Ballard and Hrbá?ek concerning nonstandard Boffa universes of sets is considerably extended.     

Micro flow injection analysis combined with a separation technique for the urinary glucose assay.

A urinary glucose assay has been investigated, employing a micro flow injection analysis (microFIA) combined with a separation technique of glucose from the analyte. The adsorption part using activated alumina for the glucose in the analyte can be successively integrated onto a microFI chip. The selective adsorption-desorption of glucose in the artificial urine can progress on the adsorption part. Along with this selective preconcentration of glucose, the typical FI peak of glucose can be obtained just by feeding the sample and deionized water as an elutant sandwiched with the reagent on the carrier stream. The glucose concentration in artificial urine can be quantitatively determined with the present microFIA system, while the interference of other components coexisting in urine occurs in the case of the conventional FIA system without any separation part. The described method serves as a template for improving the selectivity for the analyte in the multi-component system.     

Sensitive derivatizatton reagents for the resolution of carboxylic acid enantiomers by high-performance liquid chromatography

Two highly sensitive, chiral derivatization reagents, D- and L-1-aminoethyl-4-dimethyl-aminonaphthalene, were synthesized from 1-dimethylaminonaphthalene. Condensation of carboxylic acids with the chiral reagent was readily effected in the presence of a watersoluble carbodiimide. The diastereoisomeric amides formed from N-acetylamino acid and α-arylpropionic acid enantiomers were efficiently resolved by normal phase chromatography (μPorasil column) -with hexane/ethyl acetate or hexane/tetrahydrofuran as a mobile phase. With a fluorescence detector (excitation 320 nm, emission 395 nm), the detection limit was 0.1 ng.     

Iodobenzene-catalyzed alpha-acetoxylation of ketones. in situ generation of hypervalent (diacyloxyiodo)benzenes using m-chloroperbenzoic acid

Reported here for the first time is the iodobenzene-catalyzed alpha-oxidation of ketones, in which diacyloxy(phenyl)-lambda3-iodanes generated in situ act as real oxidants of ketones and m-chloroperbenzoic acid serves as a terminal oxidant. Oxidation of a ketone with m-chloroperbenzoic acid in acetic acid in the presence of a catalytic amount of iodobenzene, BF3.Et2O, and water at room temperature under argon affords an alpha-acetoxy ketone in good yield. p-Methyl- and p-chloroiodobenzene also serve as efficient catalysts in this direct oxidation. We found that when the reaction was carried out in the absence of a catalytic amount of iodobenzene, Baeyer-Villiger oxidation of a ketone took place. It is noted that use of water and BF3.Et2O is crucial to the success of this alpha-acetoxylation.     

A recyclable catalyst for asymmetric transfer hydrogenation with a formic acid-triethylamine mixture in ionic liquid

A novel task-specific ionic ligand with an imidazolium salt moiety was synthesized, and its catalytic ability and recyclability for asymmetric transfer hydrogenation of acetophenone derivatives with a formic acid-triethylamine azeotropic mixture in an ionic liquid [bmim][PF6] was examined.     

Solid-state polymerization of N-carboxy-L-leucine anhydride crystals in n-hexane

4-Isobutyloxazolidinedione, L -leucine N-carboxy anhydride, was polymerized to produce high molecular weight polymer with triethylamine in n-hexane which is not a solvent for the N-carboxy anhydride and poly-L -leucine. It was found that as the crystal size became smaller, the total surface area was increased, the initial rate of polymerization was increased, and inherent viscosity of the formed polymer was decreased.     

Pd/C-catalyzed chemoselective hydrogenation in the presence of diphenylsulfide

[Structure: see text] A Pd/C-catalyzed chemoselective hydrogenation using diphenylsulfide as a catalyst poison has been developed. This methodology selectively hydrogenates olefin and acetylene functionalities without hydrogenolysis of aromatic carbonyls and halogens, benzyl esters, and N-Cbz protective groups.