A numerical scheme for the solution of axisymmetric radiative transfer problems in irregular domains filled by media with opaque and transparent diffuse and specular boundaries

This paper presents a new numerical scheme of the discrete ordinates method for the solution of axisymmetric radiative transfer problems in irregular domains filled by media with opaque and transparent diffuse and specular (Fresnel) boundaries and interfaces. New test problems of radiative transfer, which describe radiative transfer in domains with Fresnel interfaces, are proposed in this paper. These problems admit analytic solutions and can be used as benchmark ones. The proposed scheme is applied to the solution of the problems. Numerical results show that the presence of Fresnel interfaces leads to an appreciably larger error in numerical solution. This is connected with the “discontinuity” of the Fresnel reflectivity, which, through numerical diffusion, leads to the distortion of numerical solution. Modification of the scheme allows to reduce the numerical error.     

Synthesis of Tricyclic Diesters from 8-Acetoxytricyclodec-3-ene Monoester

Tricyclic diesters were synthesized in yields of 70.4–90.8% by the addition of С₂–С₅ monobasic carboxylic acids to tricyclo[5.2.1.0^2,6]dec-3-еn-8-yl acetate in the presence of a BF₃·OEt₂ catalyst. One of the synthesized diesters, tricyclodec-3,8-diyl diacetate, has a pleasant smell with a citrus scent and can be used in different perfume compositions as a flavoring.     

Synthesis of σ-platinum cyclopentadienyl derivatives of manganese and rhenium carbonyl compounds

Russian Chemical Bulletin -     

Darzens synthesis of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid derivatives

Esters and amides of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid were prepared by the reaction of furfural with dichloroacetic acid derivatives under the conditions of the Darzens condensation. The structures of the reaction products were confirmed by their¹H NMR and IR spectra and chemical transformations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1444–1448, August, 1994.     

Fused polycyclic nitrogen-containing heterocycles 14. Intramolecular cyclization of 4-azidocarbonyl-2,5-diphenylthiazole. New route to isoquinoline derivatives

Thermolysis of 2,5-diphenylthiazole-4-carboxylic acid azide is accompanied by intramolecular cyclization to form 2-phenyl-4-H-thiazolo[4,5-c]isoquinolin-5-one through intermediate 2,5-diphenylthiazol-4-yl isocyanate.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 436–439, February, 2005.     

Asymmetric diene synthesis of bicyclo[2.2.2]octenes in the presence of Lewis acids

Asymmetric diene synthesis of substituted bicyclo[2.2.2]octenes from (?)-menthyl acrylate and cyclohexa-1,3-diene in the presence of achiral Lewis acid catalysts (TiCl₄, AlCl₃, BBr₃, AlCl₃ · OEt₂, BBr₃ · OEt₂) was studied. The influence of various factors on the isomeric composition, yield, and enantiomeric purity of the compounds prepared was examined.     

Fused polycyclic nitrogen-containing heterocycles 13. Synthesis of 6-phenyl-2-phenylimino-6H-1,3,4-thiadiazine-5-carboxylic acid and its intermolecular cyclodehydration accompanied by sulfur extrusion to form dipyrazolo[1,5-a,1′,5′d]pyrazine

Condensation of methyl phenylchloropyruvate with 4-phenylthiosemicarbazide proceeds as the Bose reaction to form 5-methoxycarbonyl-6-phenyl-2-phenylimino-6H-1,3,4-thiadiazine, which is hydrolyzed to give carboxylic acid. In the presence of polyphosphoric acid, the latter undergoes intermolecular cyclodehydration accompanied by sulfur extrusion to yield dipyrazolo [1,5-a,1′,5′d]pyrazine.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 432–435, February, 2005.