Fluorine-containing carbocations. II. Polyfluorinated benzyl cations

When dissolved in SbF₅, polyfluorinated trifluoromethylbenzenes produce polyfluorinated α,α-difluorobenzyl ions. The ¹⁹F chemicals shifts and spin-spin coupling constants J(FF) have been analysed in terms of the resonance structures which contribute to the overall positive charge distribution. The influence of halogen atoms situated at position 4 on the downfield signal shift of α-fluorines follows the sequence F > Cl > Br which is opposite to that observed for 4-XC₆H₄CF₂⁺ ions.     

Dibenzodiazepines in reactions of 2-acetyl-dimedone with 3,4-diaminobenzophenone

The reactions of 2-acetyldimedone and 2-acetyl-3-methoxy-5,5-dimethylcyclohex-2-en-1-one with 3,4-diaminobenzophenoneproduce2-[1-(2-amino-5-benzoylphenyl)amino]ethylidene-5,5-dimethyl-1,3-cyclohexanedioneand 2-acetyl-3-(2-amino-5-benzoylphenyl)amino-5,5-dimethylcyclohex-2-en-1-one, which are cyclized by the action of hydrochloric acid, yielding the respective hydrochlorides of 8-benzoyl- and 7-benzoyl-3,3,11-trimethyl-2,3,4,5-tetrahydro-1H-dibenzo[b,e][1,4]diazepin-2-ones. Hydrolytic cleavage of the 8-benzoyl derivative leads to 2-acetyl-3-(2-amino-4-benzoylphenyl)amino-5,5-dimethylcyclohex-2-en-1-one. A similar cleavage to form 2-acetyl-3-(2-aminophenyl)amino-5,5-dimethylcyclohex-2-en-1-one is observed for the known hydrochloride of 3,3,11-trimethyl-2,3,4,5-tetrahydro-1H-dibenzo[b,e][1,4]diazepin-2-one. The structures of the products were confirmed by PMR spectra and x-ray diffraction data.Riga Technical University, Riga LV-1658. Latvian Institute of Organic Chemistry, Riga LV-1006. University of Cincinnati, Ohio, USA. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 379–391, March, 1997.     

Synthesis and regioselectivity of the [3,3]-sigmatropic rearrangement of substituted 2-allylthio- and 2-allylseleno-1,4-dihydropyridines

The reaction of 3-cyano-1,4-dihydropyridine-2-thiolates and the corresponding selenolates with allyl bromide gave 2-allylthio- and 2-allylseleno-3-cyano-1,4-dihydropyridines, which, upon heating in various solvents or in the solid state, undergo [3,3]-sigmatropic rearrangement to give 3-cyano-3-allyl-1,2,3,4-tetrahydropyridine-2-thiones and the corresponding selenones. The resultant pyridinethiones are alkylated by alkyl halides at the sulfur atom and are oxidized by iodine to give disulfides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1888–1895, August, 1991.     

Cubane derivatives

The reduction of 1-bromo-9,9-ethylenedioxypentacyclo[4.3.0.0^2,5.0^3,8.0^4,7]nonane-4-carboxylic acid (2) with lithium aluminum hydride and aluminum hydride in THF was studied. A new effective method for preparing 1-bromo-9,9-ethylenedioxypentacyclo[4.3.0.0^2,5.0^3,8.0^4,7]-non-4-ylcarbinol (1) based on reduction of2 with AlH₃ under mild conditions was developed.     

Molecular structures of β-amino-α-bromovinyl trifluoromethyl ketones

The molecular structures of β-amino-α-bromovinyl trifluoromethyl ketones was studied by UV, IR, ¹H, ¹³C, and ¹⁵N NMR spectroscopy and using the density functional (B3LYP/6-31G(d,p) and PBE/QZ3P) and ab initio riMP2/cc-pVTZm quantum-chemical calculations. Factors affecting stabilization of the EZE-conformation of the molecules, which is atypical of analogous unsubstituted amino enones, are considered.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 102–106, January, 2005.     

Ideal fluid with the equation of state ε=p in the field of a plane gravitational wave

An exact solution of the equations of relativistic hydrodynamics is obtained for a semiinfinite ideal fluid with the equation of state =p in the field of a plane gravitational wave.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 99–102, November, 1982.     

Enrichment of sea-salt aerosols in short-lived222Rn daughter products-role of marine Fe/III/ hydroxide colloid

The interaction of short-lived Rn-daughter products /SLDP/, viz.²¹⁴Pb and²¹⁴Bi dissolved in sea-water with Fe/III/ hydroxide colloids followed by flotation of combined Fe-SLDP particles at the sea-air interface subsequently generating marine aerosols enriched in²¹⁴Bi and²¹⁴Pb have been studied under laboratory conditions. Rate constants for attachment of²¹⁴Bi and²¹⁴Pb to dispersed Fe/III/ colloids in the sea water are found to be 3.7×10^–4 min^–1 litre [g/Fe/]^–1 and 2.4×10^–4 min^–1 litre [g/Fe/]^–1, resp., /20°C/ over the concentration range of iron /III/ from 8 to 120 g liter^–1. The suggested mechanism of colloid flotation and aerosol generation might be responsible for some peculiarities of SLDP distribution in the lower marine atmosphere.     

Self-oscillations in the cool-flame combustion of a model n-heptane-isooctane mixture

Self-oscillation found experimentally in the cool-flame combustion of a model n-heptane-i-octane mixture has been studied in dependence on the composition of the reaction mixture. Calculations based on the CSTR model are in qualitative agreement with experimental data.

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Secondary structure of crystals

Published experimental data on the dependence of the properties of crystal substances on crystal size are discussed. The dependence is of the same form for different properties and different crystal substances. When the crystal diminishes in size, its properties remain constant until the size decreases to 10⁻⁵–10⁻⁶ cm; smaller crystals considerably change their properties. It is shown that the currently available experimental data are sufficient to substantiate the notion of an “elementary unit of a solid crystal” (“crystal quantum”). The elementary unit of a crystal is regarded as a basis for the secondary structure (macrostructure) of a solid and an elementary carrier of its “crystal” properties. Due to this notion, we can interpret the vast experimental material on the real structures and properties of solids from a single viewpoint. Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 4, pp. 724–730, July–August, 1995. Translated by L. Smolina     

Chemistry of ethyleneimine

The mechanism of the reaction of N-aminoethyleneimine with some aliphatic aldehydes and with acrolein have been studied. It has been shown that the reaction takes place at the carbonyl bond C=O with the formation of hydrazones.For part II, see [1].