Ni‐Catalyzed [4+3+2] Cycloaddition of Ethyl Cyclopropylideneacetate and Dienynes: Scope and Mechanistic Insights

A detailed study of the Ni‐catalyzed [4+3+2] cycloaddition reaction between ethyl cyclopropylideneacetate and dienynes has been conducted, resulting in the development of a new method for the synthesis of compounds containing nine‐membered rings. We studied the reactivity of various dienynes, together with their substituent and conformational effects. The mechanism of the reaction was probed by examining the stoichiometric reactions of the Ni complexes and dienynes.     

Palladium-Catalyzed cross-Benzannulation of Aminoenynes with Diynes. Highly Regioselective Synthesis of Polysubstituted Anilines

Polysubstituted anilines were prepared by the palladium-catalyzed cross-benzannulation of conjugated aminoenynes 1-4 with diynes 8. The reaction proceeded in a highly regioselective manner under mild conditions, and the anilines were obtained as single regioisomers. Our method complements the well-known precedures for the preparation of polysubstituted anilines which are widely used in organic synthesis.     

Use of the MALDI BioTyper system with MALDI–TOF mass spectrometry for rapid identification of microorganisms

In a clinical diagnosis microbiology laboratory, the current method of identifying bacterial isolates is based mainly on phenotypic characteristics, for example growth pattern on different media, colony morphology, Gram stain, and various biochemical reactions. These techniques collectively enable great accuracy in identifying most bacterial isolates, but are costly and time-consuming. In our clinical microbiology laboratory, we prospectively assessed the ability of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI–TOF MS) to identify bacterial strains that were routinely isolated from clinical samples. Bacterial colonies obtained from a total of 468 strains of 92 bacterial species isolated at the Department of Clinical Laboratory at Chiba University were directly placed on target MALDI plates followed by addition of CHCA matrix solution. The plates were then subjected to MALDI–TOF MS measurement and the microorganisms were identified by pattern matching with the libraries in the BioTyper 2.0 software. Identification success at the species and genus levels was 91.7% (429/468) and 97.0% (454/468), respectively. MALDI–TOF MS is a rapid, simple, and high-throughput proteomic technique for identification of a variety of bacterial species. Because colony-to-colony differences and effects of culture duration on the results are minimal, it can be implemented in a conventional laboratory setting. Although for some pathogens, preanalytical processes should be refined, and the current database should be improved to obtain more accurate results, the MALDI–TOF MS based method performs, in general, as well as conventional methods and is a promising technology in clinical laboratories.     

Enantiodifferentiating photoaddition of alcohols to 1,1-diphenylpropene in supercritical carbon dioxide: sudden jump of optical yield at the critical density

In the enantiodifferentiating photoaddition of ROH (R = Me, Et, i-Pr) to 1,1-diphenylpropene sensitized by fructosyl 1,4-naphthalenedicarboxylate in supercritical carbon dioxide, the enantiomeric excess of photoadduct increased with increasing bulkiness of the alcohol at all pressures used, with an accompanying sudden jump at the critical density, for which the enhanced clustering of alcohol, particularly in the subcritical pressure region, was revealed to be responsible from the fluorescence spectral examinations.     

Unsaturated bond existing in tetrafluoroethylene-propylene-vinylidene fluoride terpolymer

Infrared and nuclear magnetic resonance (NMR) spectroscopies have been applied for quantitative comparison on unsaturated bonds in tetrafluoroethylene (TFE)-propylene (P)-vinylidene fluoride (VdF) terpolymers. These spectroscopies have led to consistent results while they are based on completely different principles. It is shown that the absolute concentration can be evaluated from NMR measurements. The behavior of unsaturation has been discussed in terms of after-treatment such as wet and dry treatments. The result obtained here can give the important information to improve the performance of fluoroelastomer based on TFE-P-VdF terpolymers.     

Regional distribution of manganese,iron, copper,and zinc in the rat brain during development

Manganese (Mn), iron (Fe), copper (Cu), and zinc (Zn) concentrations were determined in the brain regions of normal 1-, 3-, 5-, 7-, 14-, 21-, 42-, 77-, and 147-day-old Wistar rats using inductively coupled plasma mass spectrometry (ICP-MS), and their maps were illustrated in color to visually compare the distribution of the elements at various stages of the growth process. Sagittal slices (1-mm thickness) sectioned at the level of the substantia nigra were divided into 18 regions, and the small slice samples were digested in microwave-assisted closed vessels for ICP-MS measurement. Mn, Fe, Cu, and Zn concentrations increased region-specifically with age, and their distributional maps showed some characteristics. These findings are discussed in terms of needs for these trace elements in the normal brain. Among new findings about their brain distribution, it is especially noteworthy that higher concentrations of Mn, Fe, and Zn were observed in the substantia nigra compared with those in neighboring regions. The mapping method in this work is expected to open up possibilities for screening of the in vivo element–element interrelationships among these essential elements.     

Intramolecular catalytic Friedel-Crafts reactions with allenyl cations for the synthesis of quinolines and their analogues

[reaction: see text] This paper describes a novel method to synthesize a quinoline backbone by incorporating allenyl cations into a catalytic intramolecular Friedel-Crafts reaction. The initial products were isomerized and aromatized upon treatment with acid and base, respectively, to give quinolines. The basic concept also proved to be promising for 1-benzazepine, 1-benzazocine, or isoquinoline synthesis.     

Toward the assembly of heparin and heparan sulfate oligosaccharide libraries: efficient synthesis of uronic acid and disaccharide building blocks

The monosaccharide moieties found in heparin (HP) and heparan sulfate (HS), glucosamine and two kinds of uronic acids, glucuronic and iduronic acids, were efficiently synthesized by use of glucosamine hydrochloride and glucurono-6,3-lactone as starting compounds. In the synthesis of the disaccharide building block, the key issues of preparation of uronic acids (glucuronic acid and iduronic acid moieties) were achieved in 12 steps and 15 steps, respectively, without cumbersome C-6 oxidation. The resulting monosaccharide moieties were utilized to the syntheses of HP/HS disaccharide building blocks possessing glucosamine-glucuronic acid (GlcN-GlcA) or iduronic acid (GlcN-IdoA) sequences. The disaccharide building blocks were also suitable for further modification such as glycosylation, selective deprotection, and sulfation.     

Synthesis and in vitro evaluation of botryllazine B analogues as a new class of inhibitor against human aldose reductase

Botryllazine B analogues of diverse substitution patterns have been prepared, and their in vitro inhibitory activities against recombinant human aldose reductase (h-ALR2) evaluated. Among the 15 compounds tested, 6-(4-aminophenyl)-2-(4-hydroxyphenyl)carbonylpyrazine (7b) proved to be the most potent inhibitor, with IC₅₀=0.91 μM. Kinetic analyses of 7b and botryllazine B (1) revealed that these inhibitors exhibit an unprecedented mixed-type inhibition on h-ALR2 with respect to the substrate d,l-glyceraldehyde, in the presence of NADPH at inhibitor concentrations near the IC₅₀ values.