Theoretical and experimental study on the in-plane S(N)2-type substitution reaction of haloalkenes with inversion of configuration at the sp(2) carbon

[reaction: see text] The intramolecular in-plane S(N)2 type reaction of haloalkene E-8a was predicted to be a facile process for the first time by DFT calculations (B3LYP/6-31+G(d),SCRF(dipole, solvent = DMF)) (DeltaG = 14.4 kcal/mol). The prediction was confirmed experimentally. When E-8a was treated with NaH in DMF, benzofuran was obtained in 95% yield. On the other hand, Z-8a was recovered quantitatively even after heating at 110 degrees C.     

Characteristics of NaI detector in positron imaging device HEADTOME employing circular ring array

In positron emission computed tomographs employing circular ring arrays of detectors, the performance of the imaging device has been specified ultimately by the characteristics of the detector. The responses of NaI detector were studied when detecting positron annihilation photon (511 keV). The study was mainly by using the NaI detector used in hybrid emission computed tomography (CT) "HEADTOME" we had developed. A series of measurements were carried out positioning two detectors with 40 cm distance and scanning 22Na point source in water. Both detectors was inclined from 0 degrees through 30 degrees to change incident angle of positron annihilation toward crystal face. Energy window was set from 100 to 700 keV. The results were presented as follows: Shortening the crystal length from 7 to 5 cm made sensitivity decrease about 10% and resolution deteriorate about 1 mm (FWHM). As the results of varying the width of the crystal, 20 mm width was optimal at any incident angle. The lead septum between the detectors was the thickness of 4 mm enough to reject multiple detector interactions (crosstalk). Beam mask which was made of lead in order to improve spatial resolution and placed on crystal face worked effectively for incident angles from 0 degrees to 15 degrees but degraded uniformity of spatial resolution from 0 degrees to through 30 degrees.     

Palladium-catalyzed reaction of 2-hydroxy-2-methylpropiophenone with aryl bromides: a unique multiple arylation via successive C-C and C-H bond cleavages

2-Hydroxy-2-methylpropiophenone undergoes a unique multiple arylation via C-C and C-H bond cleavages upon treatment with excess aryl bromides in the presence of a palladium catalyst to give 1,1,2,2-tetraarylethanes and 4,4-diaryl-1-phenylisochroman-3-ones.     

The first isolation of allenylselenonium salts: their synthesis and properties as electrophiles

The first synthesis of allenylselenonium salts and their reactivities are described. The corresponding allenyl methyl selenides were alkylated with methyl trifluoromethanesulfonate to afford the desired compounds. Their reactions with active methylene carbanions produced furan, dihydrofuran or methylene cyclopropane derivatives via the Michael addition of nucleophiles to the selenonium salts.     

High-performance liquid chromatographic method for monitoring leupeptin in mouse serum and muscle by pre-column fluorescence derivatization with benzoin

A high-performance liquid chromatographic method is described for the determination of leupeptin, a possible therapeutic drug for muscular dystrophy, in mouse serum and muscle. Leupeptin is reduced with sodium borohydride to leupeptinol, and then converted to a fluorescent derivative with benzoin. The derivative is separated on a reversed-phase column (LiChrosorb RP-18) with isocratic elution and determined with fluorescence detection. The detection limits of leupeptin in serum and muscle are 250 pmol/ml (107 ng/ml) and 500 pmol/g (214 ng/g), respectively, corresponding to approximately 150 fmol each in a 100-microliters injection volume. This method is simple and sensitive enough to permit the quantification of leupeptin in biological samples from mice dosed with leupeptin.     

Ketone synthesis by intramolecular acylation of organorhodium(I) with ester

New cyclization reactions forming cyclic ketones were developed wherein an intermediate organorhodium(I) species underwent intramolecular acylation with an ester group. A 2-norbornanone skeleton is constructed in a single operation through successive multiple carbon-carbon bond formation. The reactions ended up with generation of an alkoxyrhodium(I) species to promote the next catalytic cycle.     

Highly-efficient metal-free organic dyes for dye-sensitized solar cells

A solar-to-electric conversion efficiency of 6.1% is achieved with this new dye, compared to 6.3% for N3 dye under the same experimental conditions. Although these indoline dyes are slightly less efficient than N3 dye, the cost of indoline dye is much less than for N3 due to ease of preparation. Furthermore, indoline dyes are shown to be highly stable to photoredox processes by cyclic voltammogram.