5,6-Dihydro-4h-imidazole[4,5,1-i,j]quinoline derivatives

2-Alkyl(dialkyl)amino derivatives of I and their respective cyclic ammonium salts were obtained by reaction of the 2-chloro derivative of 5,6-dihydro-4H-imidazole [4,5,1-i,j ]quinoline (I) and its methiodide with amines. The eycloammonium salt was converted into 2-amino(alkylimino)-l,2-dihydro derivatives of 5. Methoxy- and methyl-substituted I readily formed 2-amino derivatives by reaction with sodium amide. Comparison of the UV spectra of the 2-amino derivative of I and its fixed tautomeric form indicates that the 2-amino derivative of I exists primarily in the amino form in dioxane and CC14.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1410–1413, October, 1970.     

Fluorine-containing azoles. 2. Reaction of imidazole,benzimidazoles, and perimidines with difluorocarbene

The reaction of difluorocarbene, generated from difluorochloromethane in an alkaline medium or from sodium trifluoroacetate in a neutral medium, with imidazole, tetrahydrobenzimidazole, benzimidazoles, and perimidines leads to the production of their N-difluoromethyl-substituted derivatives.See [1] for communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 520–523, April, 1984.     

Fluorine-containing azoles. 3. Reaction of imidazoles and perimidines with perfluoroalkenes

Trifluorochloroethylene, tetrafluoroethylene, hexafluoropropylene, and ,,-trifluorostyrene add to imidazole, 2-alkylbenzimidazoles, and perimidines in the presence of aqueous solutions of potassium hydroxide or fluoride to give the corresponding N-fluoroalkylazoles.See [1] for communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 524–528, April, 1984.     

Transformations of imidazo[4, 5-f]quinoline

Treatment of imidazo[4, 5-f]quinoline and some of its 3-substitmion products with methyl halides and methyl benzenesulfonate gives as the main reaction products N-methylimidazoquinolinium salts, which can also be synthesized from 5, 6-dimainoquinolines. Methylation at the N atom of the imidazole ring is only a side reaction. Treatment with trimethylphenylammonium hydroxide introduces a methyl radical into the NH group of imidazoquinoline, giving a mixture of 1-and 3-substitution products.     

Benzo[1,2-d:3,4-d′]diimidazole derivatives

A new path for the synthesis of 3-monoalkyl- and 3,6-dialkyl-substituted benzo[1,2-d:3,4-d']-diimidazole is described: 5-tosylamino-1-alkylbenzimidazole is converted to the 4-nitro derivative by nitration in glacial acetic acid, and the imidazole ring is closed after alkylation and cleavage of the tosyl group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1406–1409, October, 1970.     

Steady streaming around a spherical drop displaced from the velocity antinode in an acoustic levitation field

The steady (acoustic) streaming associated with a sphericaldrop displaced from the velocity antinode of a standing waveis studied. The ratio of the particle size to the acoustic wavelengthis treated as small but non-zero, and the solution is developedin the form of a two-term expansion in terms of the correspondingsmallness parameter. The drop viscosity is assumed to be muchhigher than that of the surrounding fluid, which is the casefor a drop in a gas medium. There are essentially three distinctregions where the steady streaming flow is analysed: insidethe drop (internal circulation), in the Stokes shear-wave layerat the surface on the gas side, and the gas outside the Stokeslayer (the outer streaming region). Solutions for the internalcirculation and the outer streaming are obtained in the limitof small Reynolds number. Despite the gas-to-liquid viscosity ratio being small, the outerstreaming may be dramatically affected by the fact that thesphere is liquid as opposed to solid. The parameter that measuresthe effect of liquidity is essentially the viscosity ratio dividedby the relative (to the particle size) thickness of the Stokeslayer. The case of a solid sphere is recovered by letting thisparameter go to zero.     

Spontaneous transition of turbulent flames to detonations in unconfined media

A deflagration-to-detonation transition (DDT) can occur in environments ranging from experimental and industrial systems to astrophysical thermonuclear (type Ia) supernovae explosions. Substantial progress has been made in explaining the nature of DDT in confined systems with walls, internal obstacles, or preexisting shocks. It remains unclear, however, whether DDT can occur in unconfined media. Here we use direct numerical simulations (DNS) to show that for high enough turbulent intensities unconfined, subsonic, premixed, turbulent flames are inherently unstable to DDT. The associated mechanism, based on the nonsteady evolution of flames faster than the Chapman-Jouguet deflagrations, is qualitatively different from the traditionally suggested spontaneous reaction-wave model. Critical turbulent flame speeds, predicted by this mechanism for the onset of DDT, are in agreement with DNS results.