Synthesis and Crystal Structure of 3,5-Dicyano-2,6-diethylthiopyridine

3,5-Dicyano-2,6-diethylthiopyridine has been synthesized by the alkylation of cyanothioacetamide with ethyl iodide in DMF and its molecular and crystal structures have been investigated. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1351–1354, September, 2005.     

Modulation instability of Stokes wave → freak wave

Formation of waves of large amplitude (freak waves, killer waves) at the surface of the ocean is studied numerically. We have observed that freak waves have the same ratio of the wave height to the wave length as limiting Stokes waves. When a freak wave reaches this limiting state, it breaks. The physical mechanism of freak wave formation is discussed.     

Regioselective Synthesis and Properties of 6-Amino-3-carbamoyl-5-cyano-3,4-dihydrospirocyclohexane-4-pyridine-2-thiol and 5-Cyano-3-thiocarbamoyl-4-spirocyclohexanepiperidine-2,6-dione

Treatment of monothiomalonodiamide with cyclohexylidenemalononitrile or cyclohexylidenecyanoacetic ester in the presence of sodium ethylate gave 6-amino-3-carbamoyl-5-cyano-3,4-dihydrospirocyclohexane-4-pyridine-2-thiol and 5-cyano-3-thiocarbamoyl-4-spirocyclohexanepiperidine-2,6-dione. Their alkylation and hydrolysis have been studied.     

Synthesis of N-methylmorpholinium 6-methyl-4-(2-thienyl)-5-phenylcarbamoyl-3-cyano-1,4-dihydropyridine-2-thiolate and its reaction with various functionally substituted methyl halides

Condensation of the anilide of acetoacetic acid, thiophene aldehyde, cyanothioacetamide and N-methyl-morpholine gave N-methylmorpholinium 6-methyl-4-(2-thienyl)-5-phenylcarbamoyl-3-cyano-1,4-dihydropyridine-2-thiolate which reacted with various halides ZCH₂Hal or H₂NCOCH(Ph)Cl to give substituted 2-ZCH₂-thio or 2-H₂NCOCH(Ph)-thio-1,4-dihydropyridines.     

Turbulent mixing of small-obstacle-induced perturbations with the separated shear layer behind a backward-facing step

In the present paper, we consider one of the most efficient and simple methods to additionally intensify the exchange processes and heat transfer in the separated flow behind a backward-facing step. The method uses small obstacles installed upstream the step; such obstacle act as turbulators smaller in size than the main obstacle. As the turbulators, solid mini ribs, comb ribbings, and wall-detached mini ribs were used. Intensification of the turbulent mixing process behind the main obstacle occurs due to the introduction of small-obstacle-induced 2D and 3D perturbations into the separated shear layer behind the step. Results of a detailed experimental study of the distributions of pressure and heat transfer for different heights of the small intensifier and its positions with respect to the step are reported. The influence of intensifier shape on the thermal and dynamic characteristics of the flow has been analyzed. The distributions of pressure and heat-transfer coefficients were used to evaluate the effectiveness of the various mini obstacles and the limits of their action on the drag and heat transfer.     

First example of [3,3]-sigmatropic rearrangement in the series of 2-(prop-2-yn-1-ylsulfanyl)-1,4,5,6,7,8-hexahydroquinolines

Russian Journal of Organic Chemistry -     

Isovaleric Aldehyde in the Synthesis of 4-Isobutyl-Substituted Pyridine-2(1H)-thiones, 4H-Pyrans, and 1,3-Cyclohexadiene

Cyclocondensation of isovaleric aldehyde with various CH acids [benzoylacetonitrile, malononitrile, cyanothioacetamide, 4-hydroxycoumarin, resorcinol, 3-phenylpyrazol-5(1H)-one, 3-morpholinocrotonanilide] in the presence of amines yields isobutyl-substituted 4H-pyrans, 1,3-cyclohexadiene, and pyridine-2(1H)-thiones. The latter compounds were used in the synthesis of substituted 2-pyridino thioethers and thieno[2,3-b]pyridine.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 3, 2005, pp. 476–482.Original Russian Text Copyright © 2005 by Dyachenko.