Synthesis and characterization of new heterocyclic derivatives by oxidation of 1‐amino‐2‐methylindoline

1‐Amino‐2‐methylindoline is a precursor used in the synthesis of antihypertension drugs. It reacts with monochloramine to lead to the formation of 1‐amino‐2‐methylindole and azo(2‐methyl)indoline. These new products have been isolated and characterized by microanalysis, uv, gc/ms, ir, and ¹H/¹³C nmr. The reaction leads to the transient formation of an indolic aminonitrene. 1‐Amino‐2‐methylindole formation proceeds in strongly alkaline medium by rearrangement of a diaziridine intermediate. In neutral or slightly alkaline medium, one obtains a precipitate of tetrazene type (‐N‐N=N‐N‐), the azo(2‐methyl)indoline. The study of the thermochemical properties shows that tetrazene decomposes towards 150 °C to give the 1,1′‐bi(2‐methyl)indoline. The stability of the starting reagents and products was the subject of a systematic investigation. A reaction mechanism is proposed.     

XAS and XRD studies of rhenium-oxygen compounds

X-ray absorption near-edge spectroscopy (XANES) of the L₁-edge of rhenium-oxygen compounds in solid and liquid state was performed. The informations obtained by this method and by single-crystal diffraction are discussed.     

Single particle excitations in Ba from a ( , t) reaction study

The ¹³⁰Ba( ¹²⁹Ba reaction was studied with 25 MeV deuterons and excellent energy resolution. About 50 excited states have been observed up to E_x = 2.0 MeV and for 42 of them transferred ℓ values and/or J^π values were assigned on the basis of the measured angular distributions and asymmetries. The level scheme of ¹²⁹Ba, the neutron pickup strength distribution and the known electromagnetic decay scheme are compared with results of calculations with the interacting boson-fermion model. These simple multi-shell IBFM-1 calculations describe well the main features of the experimental data.     

All-electron and relativistic pseudopotential studies for the group 1 element polarizabilities from K to element 119

Two-component and scalar relativistic energy-consistent pseudopotentials for the group 1 elements from K to element 119 are presented using nine electrons for the valence space definition. The accuracy of such an approximation is discussed for dipole polarizabilities and ionization potentials obtained at the coupled-cluster level as compared to experimental and all-electron Douglas-Kroll results.     

Link between population dynamics and dynamics of Darwinian evolution

We provide the link between population dynamics and the dynamics of Darwinian evolution via studying the joint population dynamics of similar populations. Similarity implies that the relative dynamics of the populations is slow compared to, and decoupled from, their aggregated dynamics. The relative dynamics is simple, and captured by a Taylor expansion in the difference between the populations. The emerging evolution is directional, except at the singular points of the evolutionary state space. Here "evolutionary branching" may occur. The diversification of life forms thus is demonstrated to be a natural consequence of the Darwinian process.     

Measurement of the spin asymmetry in the photoproduction of pairs of high- p(T) hadrons at HERMES

We present a measurement of the longitudinal spin asymmetry A(||) in photoproduction of pairs of hadrons with high transverse momentum p(T). Data were accumulated by the HERMES experiment using a 27.5 GeV polarized positron beam and a polarized hydrogen target internal to the HERA storage ring. For h(+)h(-) pairs with p(h(1))(T)>1.5 GeV/c and p(h(2))(T)>1.0 GeV/c, the measured asymmetry is A(||) = -0. 28+/-0.12(stat)+/-0.02(syst). This negative value is in contrast to the positive asymmetries typically measured in deep inelastic scattering from protons, and is interpreted to arise from a positive gluon polarization.     

Sterically crowded cyclopropanation catalysts. Syn-selectivity using rhodium(III)porphyrins

Rhodium(III)porphyrins catalyze the decomposition of ethyl diazoacetate and the transfer of ethoxy-carbonylcarbene to alkenes to form cyclopropanes in moderate to high yields. When compared with other catalysts a large syn-selectivity was observed on reaction with cis-alkenes. This selectivity increased with the size of the substituents, and suggested a preferential direction of approach of the alkene towards a rhodium—carbene complex.