Synthesis of (+)-goniopypyrone and (+)-goniotriol using Pd-catalyzed carbonylation

Syntheses of (+)-goniopypyrone and (+)-goniotriol isolated from Goniothalamus giganteus were achieved. The key steps involve Pd-catalyzed carbonylation for lactone ring formation and diastereoselective reduction of ynone using the (R)-CBS catalyst and borane dimethyl sulfide complex.     

Unusual Photoreaction of Triquinacene within Self‐Assembled Hosts

Triquinacene is a concave tricyclic hydrocarbon with diverse photoreactivity. In the cavity of an electron‐accepting molecular host, triquinacene was specifically photooxidized at the peripheral allylic position into an alcohol, 1‐hydroxytriquinacene, via guest‐to‐host electron transfer. The unusual reactivity stems from the extremely electron‐deficient triazine panel ligand of the host cage, which allows the cage to function as a good electron acceptor. Thus, self‐assembled coordination cages can serve not only as molecular‐sized reaction vessels but also function electronically as redox media. Dissolved molecular oxygen is indispensable for the photoreaction and immediately traps a photogenerated radical.     

Preparation and applications of novel fluoroalkyl end‐capped oligomers/polyimide/silica nanocomposites

Fluoroalkyl end‐capped acrylic acid, N,N‐dimethylacrylamide, N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide and vinyltrimethoxysilane oligomers reacted with polyamic acid possessing trimethoxysilyl groups under alkaline conditions to yield the corresponding fluoroalkyl end‐capped oligomers/polyamic acid/silica nanocomposites. These isolated fluorinated composite powders were found to afford nanometer size‐controlled fine particles with a good dispersibility and stability in water and traditional organic solvents. We succeeded in preparing new fluoroalkyl end‐capped oligomers/polyimide/silica nanocomposites by the imidization of fluorinated polyamic acid silica nanocomposites through the stepwise heating at 110 and 270°C under air atmosphere conditions. These fluorinated polyimide/silica nanocomposites thus obtained were applied to the surface modification of glass and poly(methyl methacrylate) (PMMA) to exhibit good hydro‐ and oleo‐phobic characteristics imparted by fluoroalkyl groups in the composites on their surface. In addition, the surface morphology of the modified glass treated with these fluorinated nanocomposites were analyzed by using FE‐SEM and DFM. Copyright © 2011 John Wiley & Sons, Ltd.     

A Dicyanomethylene‐Substituted Triangulene: Effects of Molecular‐Symmetry Reduction and Electron‐Accepting Substituents on a Fused Polycyclic Neutral π‐Radical System

A triangulene‐based C₂‐symmetric 33 π‐conjugated stable neutral π‐radical, 2^. , which possesses two dicyanomethylene groups and one oxo group, has been designed, synthesized, and isolated as an analogue of tris(dicyanomethylene) derivative 1^. and trioxo derivative TOT^. with C₃ symmetry. Effects of molecular‐symmetry reduction and electron‐accepting substituents on this fused polycyclic neutral π‐radical system were studied in terms of their molecular structure, electronic‐spin structure, and electrochemical and optical properties with the help of theoretical calculations. Interestingly, this system ( 2^. ) has a four‐stage redox ability, like TOT^. , as well as low frontier energy levels and a small SOMO–LUMO gap, similar to 1^. , in spite of the loss of the degenerate LUMOs in symmetry‐lowered 2^. , which is associated with the attachment of the weaker electron‐accepting oxo group instead of the dicyanomethylene group in 1^. . These prominent results are attributable to the structural and electronic properties in the triangulene‐based highly delocalized fused polycyclic neutral π‐radical system.     

Identification of low-abundance proteins of bovine colostral and mature milk using two-dimensional electrophoresis followed by microsequencing and mass spectrometry

We identified several low-abundance proteins of bovine colostrum and mature milk using the immunoabsorption technique and two-dimensional electrophoresis (2-DE) followed by microsequencing and mass spectrometry. Two major milk proteins, beta-casein and immunoglobulin G (IgG), were effectively removed from the milk using immunoabsorbents. Milk samples before and after immunoabsorption were separated by 2-DE. Protein identification of the spots on 2-DE was performed by either gel comparison, microsequencing, matrix-assisted laser desorption/ionization-time of flight mass-spectrometry (MALDI-TOF-MS), peptide mass fingerprinting or peptide sequencing using tandem MS by hybrid quadrupole/orthogonal acceleration time of flight-MS (Q-TOF). Significant differences in protein patterns were observed between the low-abundance proteins of colostrum and mature milk. In addition, several low-abundance proteins including fibrinogen beta-chain, chitinase 3-like 1, alpha-antitrypsin, complement C3 alpha-chain, gelsolin and apolipoprotein H were observed only in colostrum. However, the level of beta-casein fragments increased significantly during this lactation period. alpha-Lactalbumin and beta-lactoglobulin as well as some low-abundance proteins including bovine serum albumin, serotransferrin and lactoferrin were identified in both colostral and mature milk. Low-abundance proteins in bovine colostrum may have special physiologic relevance to the health and development of calves early in lactation.     

Cloth colorization caused by microbial biofilm

In this study, cloth disfeaturement was investigated biologically. To clarify whether or not microbes can cause cloth disfeaturement, and to identify the microbes causing the disfeaturement, worn cloth samples were incubated on sweat-ingredient agar medium. Non-sterilized cloth samples became yellow-colored during incubation, and bacterial strains belonging to the genera Bacillus, Brevibacterium, Kocuria, Micrococcus and Staphylococcus were isolated from the yellow-colored parts. Two major isolates close to the genera Bacillus and Micrococcus were inoculated separately or together on cloth samples to examine whether or not these isolates can cause colorization. When the isolate close to Micrococcus was inoculated on its own or mixed with the isolate close to Bacillus, the samples turned yellow to a greater extent and a biofilm-like structure was observed by SEM on the colored areas. In contrast, the isolate close to Bacillus alone barely caused any colorization, and no biofilm-like structure was observed. From the yellow-colored samples, bacterial strains with the same 16S rRNA gene sequences as those of the inoculated strains were re-isolated. These results strongly suggest that the bacterial strain belonging to genus Micrococcus causes cloth colorization by forming a biofilm structure.     

First synthesis of (+)-myxothiazol A

First convergent synthesis of (+)-myxothiazol A (1) was achieved based on modified (one-pot) Julia olefination between (3,5R)-dimethoxy-(4R)-methyl 6-oxo-(2E)-hexenamide (2), corresponding to left-side of the final molecule, and E-4-2′-(1S,6-dimethylheptadiene)-(2,4′-bis-thiazole)-4-methybenzothiazole sulfone (4) corresponding to right-side.     

Thermogravimetry of the thermal degradation of Japanese lacquer (urushi) films

The kinetics of the thermal degradation of Japanese lacquer (urushi) films in N₂ and in air were studied by means of thermogravimetry (TG). Thermogravimetric and derivative thermogravimetric curves indicated that the degradation occurred in three stages. The atmosphere influenced the apparent activation energies (E _a) of the three degradation stages. The activation energies (E _a) for the first stage in N₂ and air, obtained from the TG curve, were 19.12 and 10.19 kcal mol^?1, respectively, and the corresponding pre-exponential factors (A) were 6.18 × 10⁵ and 1.24 × 10² min^?1 for 1-year-old urushi films.