Reaction of 4-oxoalkane-1,1,2,2-tetracarbonitriles with 1,3,5-trlaryl-2,4-diaza-1,4-pentadienes

2-Aryl-1,2,3,4-tetrahydropyridine-3,3,4,4,-tetracarbonitriles and 1,3,5-triaryl-9-oxo-1,2,3,4b,5,6,8a,9-octahydropyrido[3,4:3,4]pyrrolo[1,2-a][1,3,5]triazine-4b,8a-dicarbonitriles are formed by the reaction of 4-oxoalkane-1,1,2,2-tetracarnonitriles with 1,3,5-triaryl-2,4-diaza-1,4-pentadienes depending on the solvent used.Chuvash State University, Cheboksary 428015. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1395–1409, October, 1996. Original article submitted October 2, 1996.     

Synthesis of 2,5-distributed 3,3,4,4-tetracyanopyrrolidines

The reaction of 1,1,2,2-tetracyanoethane with 1-R,3-R,5-R-2,4-diazapenta-1, 4-dienes leads to 2,5-disubstituted 3,3,4,4-tetracyanopyrrolidines. The conditions for the acylation of the last were selected.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 353–358, March, 1994.     

Reaction of 3,3,4,4-tetracyanopyrrolidines with primary alcohols and amines

2,5-Substituted 3,3,4,4-tetracyanopyrrolidines react with primary alcohols in the presence of an excess of a base or with the base itself. 2-(N-Arylideneamino)-5-alkoxy-3,4-dicyanopyrroles are formed as a result of the reactions with alcohols, and 2,5-diamino-1-R-3,4-dicyanopyrroles are formed as the result of the reaction with primary aliphatic amines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1502–1507, November, 1991.     

Chemistry of 1,1,2,2-tetracyanoethane. 11. Synthesis and stereochemical characteristics of 3-methyl-5-oxo-2′-amino-5′-phenyl -3′,4′,4′-tricyanoisoxazoline-4-spiro-1′-cyclopent-2′-ene

The Michael condensation of 1,1,2,2-tetracyanoethane with 3-methyl-4-benzylideneisoxazolin-5-one having the Z configuration leads to a heterocyclic spiran with retention of the cis orientation of the phenyl and keto groups. The deviations of the series of bond angles of the spiran from the standard values, the abnormal lengths of the C-C bonds adjacent to the gem-dicyano group, and the appearance of nonbonding >C=O(...)CN interactions and conjugation effects in the enaminonitrile fragment are discussed.For Communication 10, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1404–1410, October, 1988.     

Refinement of the structure of the products of the interaction of 4-oxoalkane-1,1,2,2-tetracarbonitriles with aldehydes

It has been established by x-ray structural analysis that on reacting 4-oxoalkane-1,1,2,2-tetracarbonitriles with aldehydes 6-imino-2,7-dioxabicyclo[3.2.1]octane-4,4,5-tricarbonitriles are formed and not 3-imino-2,6-dioxabicyclo[2,2,2] octane-4,8,8-tricarbonitriles as has been proposed. Chuvash State University, Cheboksary 428015. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 497–499, April, 1997.     

Formation pathways and structure—Property interrelationship of 3-imino-1-methyl-5,5-dialkyl-4,7,7-tricyano-2-oxabicyclo-[2.2.1]heptane derivatives

The problems of the structure—property interrelationship of 3-imino-2-oxabicyclo[2.2.1]heptane derivatives are discussed on the basis of x-ray diffraction studies (XDS). A pathway for the formation of the bicyclic compounds is proposed, and the realization of spirans in the reaction of sym-tetracyanoethane with conjugated cyclic systems containing s-cis C=C and C=O fragments is substantiated. The factors responsible for the syn orientation of the oxygen atom and the N-substituent of the imino group are analyzed. It is shown that a change in the steric hindrance in the bicyclic compounds leads to a change in the conformation of the latter. The reasons for the shortening of the C_sp3-C_sp3, C_sp3-C_sp and C=N exo bonds and the correlation of the XDS and IR spectroscopic data are examined. From the XDS data for N-bromo-substituted imines, a model for Br⁺...NC electrophilic attack was proposedCommunication 16 from the series Chemistry of 1,1,2,2-tetracyanoethane. See [1] for Communication 15.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 519–526, April, 1991.     

Initiation of combustion in multilayer energetic compositions with a high-current electron beam

Experimental results on the ignition of energetic two- and three-layer potassium picrate- and lead(II, IV) oxide-based compositions with a high-current electron beam of nanosecond duration are reported. It is shown that the sustainability of explosive transformations in layered compositions depends on the boundary conditions and the additional impact of the cathode flame (high-temperature metal plasma).     

Superfluid-insulator transition in a moving system of interacting bosons

We analyze the stability of superfluid currents in a system of strongly interacting ultracold atoms in an optical lattice. We show that such a system undergoes a dynamic, irreversible phase transition at a critical phase gradient that depends on the interaction strength between atoms. At commensurate filling, the phase boundary continuously interpolates between the classical modulation instability of a weakly interacting condensate and the equilibrium quantum phase transition into a Mott insulator state at which the critical current vanishes. We argue that quantum fluctuations smear the transition boundary in low dimensional systems. Finally we discuss the implications to realistic experiments.     

Small-Scale Analysis of Hydrodynamical Helicity Suppression in the Mean-Field Dynamo-Model

Journal of Experimental and Theoretical Physics - We compare the classical mean-field dynamo model proposed by Steenbeck, Krause, and Rädler to describe the generation of large-scale magnetic...