Oxidative reactions of azines. 12. Dehydrogenation and oxidation of 2-methyl-9-phenyl-2,3-dihydro-1H-2-azafluorene

The oxidation of 2-methyl-9-phenyl-2,3-dihydro-1H-2-azafluorene by air, manganese dioxide, and potassium permanganate has been studied. Depending on the nature of the oxidant it was found that this dihydroazafluorene derivative can be dehydrogenated to the indeno[2,1-c]pyridine anhydro base series, be hydroxylated, oxygenated, or undergo fission to a 2-formamidomethyl-substituted indan-1-one. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 724–730, May, 2006.     

Static holographic phase conjugation of vortex beams

Phase conjugation of singular (vortex) beams is performed using a static nonlinearly recorded hologram. The diagnostics of phase-conjugate optical vortices is carried out by an original method based on the Young model of diffraction phenomena. It is shown that a phase-conjugate vortex is characterized by the same topological charge as a vortex inverted by degenerate four wave mixing, differing in sign from a vortex reflected by an ordinary mirror.     

Modification of the energy spectrum and magnetic breakdown in a system of 2D holes at the GaAs/Al<Subscript>0.5</Subscript> Ga<Subscript>0.5</Subscript>As heterojunction upon uniaxial compression

Uniaxial compression of the p-type GaAs/Al_0.5Ga_0.5 As heterostructures induces magnetic breakdown between the spin-split ground-state subbands of two-dimensional heavy holes. This phenomenon serves as direct experimental evidence of a strong qualitative modification of the energy spectrum of these structures upon uniaxial deformation. This modification has been revealed by numerical calculations, and, according to it, the subband spin splitting decreases upon compression, while the contours of the hole Fermi surface in both subbands touch one another in the compression direction in a pressure range of 2.5 kbar.     

Syntheses and reactions of some fluorinated dienes,cyclobutenes and furans

There are many reports¹ of the pyrolysis of fluorinated organic compounds, including the defluorination of cyclic fluorocarbons over iron to give aromatic compounds. Extending this technique we have investigated the flow pyrolysis of some readily accessible unsaturated fluorocarbons, such as I, II, and III, and found these to be synthetically

useful routes to fluorinated dienes, cyclobutenes, and furans. Pyrolyses were carried out using a nitrogen flow over platinum, iron or caesium fluoride heated at 430–700°. The various products can all be rationalized in terms of intermediate allylic radicals, and the solid substrate influences which allylic radicals are formed.We are also investigating the chemistry of those now accessible compounds, such as IV, V, and VI, and some of the preliminary results are described.

For example the fluoride ion induced dimerisation of IV gave two major products VII and VIII via a particular interesting mechanism.

     

Syntheses of 2,2′-diimidazole

New methods of preparation of 2,2-diimidazole have been developed, by the reaction of ammonia with 1,1-dibromoacetaldehyde (20% yield) or with glyoxal sulfate (40%), and by the cyclization of 1,2-dihydroxyethylenediamine dihydrochloride in the presence of sodium acetate (yield 60%).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1069–1070, August, 1987.