New strong fibrates with piperidine moiety

New fibrates containing piperidine, 4-hydroxypiperidine, piperidin-3-ene, and piperazine moieties in the structures were synthesized and evaluated. Among the synthesized compounds, 2-[3-[1-(4-fluorobenzoyl)-piperidin-4yl]phenoxyl-2-methylpropanoic acid (9aA: AHL-157) showed very superior activities in decreasing triglyceride, cholesterol, and blood sugar compared to bezafibrate in mice and rats.     

Coulomb expansion of a van der Waals C60 solid film

Scanning tunneling microscopy study revealed a van der Waals C₆₀, solid film with 13% room-temperature lattice expansion on the GaAs(00l) 2 x 4 surface. The mechanism involves fundamental Coulomb interaction due to charge transfer from the GaAs substrate. Theoretical calculation determines the charge transfer to be 1.76 electrons per C₆₀ molecule. Oriented at its (110) crystallographic axis this film also distinguishes itself from those formed on all other semiconductor and metal substrates where only the low-energy (111) hexagonal packing of C₆₀ molecules was developed. It is shown that this is due to the one-dimensional confinement effect of the anisotropic substrate, which may have the prospect of controlling crystal growth.     

Asymmetry in the nonmesonic weak decay of polarized (5)(Lambda)He hypernuclei

We have measured the asymmetric emission of protons from the nonmesonic decay of polarized (5)(Lambda)He produced by the (pi(+), K+) reaction. (5)(Lambda)He is an s-shell hypernucleus and its polarization is due to the Lambda. One expects to obtain direct information on the elementary weak Lambda-->p-->np process. The asymmetry parameter has been determined to be 0.24+/-0.22. The implication of the result is discussed.     

On the nielsen-taylor effect in the diffusion thermopower of dilute alloys

It is suggested that the electron-phonon vertex correction to the electron-impurity scattering gives rise to an additional term in the diffusion thermopower of dilute alloys at low temperatures. The absolute magnitude of the additional term is similar to the Nielsen-Taylor term. The experiment which can detect these effects is investigated.     

A new stereoselective synthesis of (±)nootkatone by means of cyclopentenone annulation

The title sesquiterpene is synthesized by means of the new cyclopentenone annulation which involves acid-treatment of IIIb. The ester group of the resulting V is transformed selectively into isopropenyl appendage of the trans configuration to the two methyl groups. Successive ring-enlargement via a dibromomethyllithium adduct X has yielded (±)nootkatone.     

Doping and annealing effects on ESR in chemically vapor deposited amorphous silicon

The effects of phosphorus doping and annealing on localized states in the gap for CVD a-Si are investigated using ESR. A close relation between the spin density and the linewidth is found out for undoped samples suggesting that the localized states are uniformly annealed out up to 1050 °C in spite of the crystallization of the samples at 700 ～ 800 °C. The spin density also decreases with an increase of doping ratio, but the linewidth remains constant. For a heavily doped sample, a new signal with $\text{g}\text{=2.0043}$ is observed, and suggested to be due to localized states associated with incorporated phosphorus atoms.     

Synthesis of thromboxane A2 analogs—1 : (±)-Dimethanothromboxane A2

The stable thromboxane A₂ analog (±)-dimethanothromboxane A₂ 1 was synthesized from bicyclo[3.1.1]heptane 2 via the tricyclic compound 4.