Synthesis of five-, six-, and seven-membered ring lactams by CpRh complex-catalyzed oxidative N-heterocyclization of amino alcohols

A new effective catalytic system consisting of [CpRhCl(2)](2)/K(2)CO(3) (Cp = pentamethylcyclopentadienyl) for the lactamization of amino alcohols has been developed. As an example, the reaction of 3-(2-aminophenyl)-1-propanol in the presence of [CpRhCl(2)](2) (5.0% Rh) and K(2)CO(3) (10%) in acetone gives 3,4-dihydro-2(1H)-quinolinone in an isolated yield of 80%. A variety of five-, six-, and seven-membered benzo-fused lactams are synthesized by this catalytic system. [reaction: see text]     

ESR studies of europium ions in alkali chlorides and bromides

ESR studies of europium ions in alkali chlorides and bromides were performed at room and liquid nitrogen temperatures. There were first reported spin Hamiltonian parameters for NaBr: Eu²⁺ and RbBr: Eu²⁺ crystals and also for coagulated europium ions in NaCl, KCl, KBr and RbBr crystals. The dependence of b₂⁰ and b₂² on the lattice constant, a, of host crystals was discussed; a single relation b₂⁰αa^?2.6 was obtained, while relations for b₂² were treated seperately for Na, K and Rb halide series, respectively. From the relative values of b₂² and b₂⁰, displacements of the nearest neighbor anions surrounding the Eu²⁺-vacancy pair were estimated to be 0.083a for NaCl and NaBr, 0.081a for KC1, 0.080a for KBr, 0.074a for RbCl and 0.078a for RbBr.     

Some characteristics of an intensified photodiode array spectrometer system for use in plasma emission spectrometry

A 1024-element silicon photodiode array with a microchannel plate image intensifier was coupled to a Czerny-Turner spectrometer and basic characteristics of the spectrometer system were studied using an Hg lamp, a hollow cathode lamp and a d.c. argon plasma as emission sources. The intensifier proved to be useful to enhance signals without increasing the electronic background. The signal to dark current ratio of the cooled photodiode array was larger than that of a photomultiplier (HTV R457) in the wavelength region above 380 nm. Effects of entrance slit width, integration time per scan and intensifier gain on signal to background ratios and signal to noise ratio are presented and optimum conditions for emission measurements using the system are described.     

X-band ESR studies of forbidden transitions of europium ions in CaF2: Eu crystals

The characteristics of allowed and forbidden transitions of Eu²⁺ ions in CaF₂ single crystals have been investigated at room temperature. The Angular dependences of these transition intensities were theoretically calculated with the use of perturbation theory, and compared with the experimental values. The experimental results can be explained by taking into account crystal field effects $\text{(}\text{1}\text{60}\text{) b}{}_4\text{[O}{}^0{}_4\text{+ 5O}{}^4{}_4\text{]}$, and a hyper fine interaction A_iS · I_i in the spin Hamiltonian.     

Visualization of how light changes affect ion movement in rice plants using a real-time radioisotope imaging system

Journal of Radioanalytical and Nuclear Chemistry - We developed a real-time radioisotope imaging system (RRIS) technique that can nondestructively visualize the element absorption and transport...     

Relationship between third-order nonlinear optical properties and magnetic interactions in open-shell systems: a new paradigm for nonlinear optics

Although most third-order nonlinear optical (NLO) materials are closed-shell singlet systems, this Letter theoretically shows that the third-order NLO properties are drastically enhanced in symmetric open-shell diradical systems with intermediate diradical character and further reveals that this enhancement is associated with the ferromagnetic and antiferromagnetic interactions. This new paradigm opens up a promising area for designing new third-order NLO materials.     

Novel synthesis of 7-fluoro-8-(trifluoromethyl)- 1H-1,6-naphthyridin-4-one derivatives: intermolecular cyclization of an N-silyl-1-azaallyl anion with perfluoroalkene and subsequent intramolecular skeletal transformation of the resulting pentasubstituted pyridines

In this study, fluorine-containing pentasubstituted pyridine derivatives 9a-m were prepared regioselectively in good yields by the intermolecular cyclization of a variety of N-silyl-1-azaallylic anion intermediates 7, which were generated from a functionalized silane 5 and an aromatic/aliphatic nitrile 6 with perfluoroalkene 8. Also, 7-fluoro-8-(trifluoromethyl)-1H-1,6-naphthyridin-4-one derivatives 11a-k were synthesized in excellent yields by the subsequent base-promoted intramolecular skeletal transformation of the resulting pyridine derivatives 10a-k.     

Ti-direct, powerful, stereoselective aldol-type additions of esters and thioesters to carbonyl compounds: application to the synthesis and evaluation of lactone analogs of jasmone perfumes

An efficient TiCl(4)-Et(3)N or Bu(3)N-promoted aldol-type addition of phenyl and thiophenyl esters or thioaryl esters with aldehydes and ketones was performed (total 46 examples). The present method is advantageous from atom-economical and cost-effective viewpoints; good to excellent yields, moderate to good syn-selectivity, substrate variations, reagent availability, and simple procedures. Utilizing the present reaction as the key step, an efficient short synthesis of three lactone [2(5H)-furanone] analogs of jasmine perfumes was performed. Among them, the lactone analog of cis-jasmone had a unique perfume property (tabac).