Transformations of 3-methyl-2-azafluorene involving the methyl and methylene groups

The condensation of 3-methyl-2-azafluorene with benzaldehyde at the methyl group, as a result of which the cis and trans forms of 3-styryl-2-azafluorene are formed, proceeds without catalysts. The subsequent condensation with benzaldehyde takes place in the presence of potassium ethoxide and leads to 3-styryl-9-benzylidene-2-azafluorene. Treatment of azafluorene with phenoxyacetyl chloride in the presence of triethylamine yielded 3-methyl-9-(-hydroxy--phenoxyethylidene)-2-azafluorene. On the basis of the spectral data it was concluded that the latter exists in the form of a mixture of the enol form and the zwitterionic form. 3-Methyl-9-(-phenyl--cinnamoyloxyallylidene)-2-azafluorene was obtained by acylation of azafluorene with cinnamoyl chloride under the same conditions. The PMR and IR spectral data are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 79–81, January, 1978.     

Synthesis,structure and magnetic properties of a trinuclear π-cyclopentadienylniobium complex containing the formate,hydroxylic and oxygen bridges

The trinuclear complex [C₅H₅NbOOCH]₃ (OH)₂ (O)₂ was prepared by heating C₅H₅Nb(CO)₃PPh₃ with anhydrous HCOOH in xylene. The niobium atoms are located at the vertices of an almost regular triangle with short Nb?Nb distance equal to 3.14». The electronic configuration of niobium is d¹. Analysis of the magnetic properties and location of the niobium atoms indicated that they bind only by the formate, hydroxylic and oxygen bridges instead of by direct NbNb bonds.     

Differential cross sections of elastic pp scattering in the energy range 8–70 GeV

In this paper we present tables of absolute differential cross sections of elastic pp scattering together with the values of the slope parameter B and the real-part parameter α, where $\text{B=}\text{d}\text{d}\text{t}\text{In}\text{dσ}\text{d}\text{t}\text{α=}\text{Re A(0)}\text{Im A(0)}$ and A(0) is the amplitude of elastic pp scattering at t = 0. The cross-section data have been obtained at the Serpukhov accelerator from 8 to 70 GeV in the |t|-range 0.0007 ? 0.12 (GeV/c)².     

Communication networks with an emergent dynamical structure

A model with a dynamical network structure is studied. The essential difference from other models is that a disappearance of links is also allowed. The obtained results suggest that under certain conditions a fairly robust cluster, which contains all of the elements of the system, can be formed. According to the power law dependence in the node connectivity distribution, a scale-free regime can occur in such models. The average network diameter behaves as K-tau. The emergent structure is close to the small-world networks for certain values of p and to the large-world ones for others. Generally, the influence of the parameter K on the average network diameter is more significant than that of the system size.     

The electronic structure and optical and magnetooptical properties of the CaCo<Subscript>2</Subscript> compound synthesized at a high pressure: Experiment and theory

The optical properties (the real ε₁ and imaginary ε₂ permittivity parts, optical conductivity σ, and reflectivity R) of the new ferromagnetic compound CaCo₂ in the Laves cubic phase (C15) synthesized at a pressure of 8.0 GPa were studied over the spectral range ?ω = 0.2–9 eV. The field and spectral (?ω = 0.5–4.2 eV) dependences of the equatorial Kerr effect were determined. The electronic structure and optical characteristics of CaCo₂ were calculated using the electron density functional theory by the linearized augmented-plane-wave method. The main band structure parameters of the compound were determined. The experimental and theoretical σ(ω) and R(ω) dependences were in satisfactory agreement with each other. The formation of the main absorption bands was found to be caused by the (p,d → d,p)-type electronic transitions related to the cobalt and calcium atoms. The exchange splitting of the 3d band of CaCo₂ was estimated, 2Δ_exc ～ (1–1.3) eV.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-Tosylates of 4-Methoxy-1,2,3,4-tetrahydrocarbazole and 2-(6-Methoxy-1-cycloalken-1-yl)anilines

The reaction of N-tosylates of 2-(1-cycloalken-1-yl)anilines and 2,3,9a,9-tetrahydro-1H-carbazole with methanol in the presence of CuBr₂ proceeds with high regioselectivity leading to the corresponding tosylates of 2-(6-methoxy-1-cycloalken-1-yl)anilines and 4-methoxy-1,2,3,4-tetrahydrocarbazole. The latter as well as N-mesyl-1,2,3,4-tetrahydrocarbazole showed moderate cytotoxic activity with respect to HEK293 cell line.     

Diastereoisomeric 1,2,5-trimethyl-4-mtolylpiperidin-4-ols and 2,5-dimethyl-4-m-tolylpyridine

The preparation of 1,2,5-trimethyl-4-m-tolypiperidin-4-ol and the isolation of three of its diastereoisomers are described. The passage from this piperidinol to 2,5-dimethyl-4-m-tolylpyridine has been effected. Some derivatives of the latter compound have been obtained.Translated from Khimiya Geterotsiklicheskikh Soedinii, Vol. 6, No. 6, pp. 782–786, June, 1970.