Mechanism of the thio-claisen rearrangement of 3-methylallyl phenyl sulfide

The thio-Claisen rearrangement of isomeric 3- and 1-methylallyl phenyl sulfides was investigated. It is demonstrated that the thio-Claisen rearrangement of the 3-methyl isomer is preceded by its thioallyl rearrangement to the 1-methyl isomer. The latter undergoes thio-Claisen rearrangement to o-(3-methylallyl)thiophenol, which is cyclized to 2-ethyl-2,3-dihydrobenzothiophene and 2-methylthiochroman under the reaction conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1191–1194, September, 1981.     

Competitive formation of 4-aminoisoxazoles and 5-aminooxazoles in the cyclization reactions of O-alkylated hydroxyimino nitriles

Base-catalyzed cyclization of O-alkylated α-hydroxyimino nitriles gave mixtures of 4-aminoisoxazoles and 5-aminooxazoles, their ratio depending on the substituent structures and the reaction conditions. The formation mechanism of 5-aminooxazoles in this reaction is discussed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1773–1780, October, 2006.     

Three-dimensional structures of phosphorus-containing heterocycles. Communication 34. 2-Phenoxy-2-oxo-1,3,2-oxathiaphosphorinanes

Conclusions According to the data from the¹H NMR spectra, the dipole moments, and the Kerr effect, the preferred conformation of 2-aroxy-2-oxy-1,3,2-oxathiaphosphorinanes is a chair conformation with an axial orientation of the aroxy grouping and a gauche orientation of the aryl group relative to the P=O bond on the side of the cyclic oxygen atom. In the investigated compounds the p- conjugation is disrupted, as evidenced by the orthogonal orientation of the unshared pair of p electrons of the exocyclic oxygen atom and the orbitals of the benzene ring.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 570–575, March, 1985.     

Sorption of carbon dioxide by the composite sorbent “potassium carbonate in porous matrix”

Sorption of CO₂ in the presence of water vapor by the K₂CO₃—-Al₂O₃ composite sorbent was studied by IR spectroscopy in situ, X-ray diffraction analysis, and the differentiating dissolution method and reasons for a decrease in its dynamic capacity are given. The samples containing K₂CO₃·1.5H₂O in pores are characterized by the maximal dynamic capacity. A mechanism for CO₂ sorption was proposed, which qualitatively explains the obtained dependence of the capacity on the water content in the composite sorbent. A high dynamic capacity can be maintained by regeneration of the sorbents by water vapor at 170 °N. The capacity of the sorbents decreases during the first 10 sorption—regeneration cycles due to the formation of an inactive phase of potassium aluminum carbonate.     

Transformations of 2-methylthiacyclobutane in the presence of aluminum oxide

The transformations of 2-methylthiacyclobutane at 150–350 °C in the presence of -Al₂O₃ samples with different aprotic acidities were investigated. It was established that the sulfide undergoes isomerization via two pathways, viz., with ring expansion to a five-membered ring and with opening at one C—S bond to give an unsaturated thiol. An experimental confirmation of the consecutive formation of hydrogen sulfide from a one-ring sulfide through a step involving the formation of an unsaturated thiol was obtained for the first time. The transformations are realized as a result of both ionic and polymerization-depolymerization processes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 184–187, February, 1982.     

Study of acid-modified aluminum oxides produced by centrifugal thermal activation in dehydration of ethanol

Possibility of using products formed in centrifugal thermal activation of hydrargillite to obtain alumina catalysts washed to remove admixtures of alkali metals was considered. A comparison of the physicochemical and catalytic properties of the samples demonstrated that washing with water is more favorable than that with nitric acid; the catalytic activity and acid-base properties of the catalyst surface are determined not only by the content of Na, but also by the whole set of catalyst preparation conditions. The most active of the samples obtained in the study has acidity close to that of industrial aluminum oxide produced by the reprecipitation method, but surpasses it in activity: at 370°C, the total yield of ethylene and diethyl ether reaches a value of 88.8 mol %, which is 4% higher than that for the reference sample.     

Novel Reactions of Tropylium Salts with Heterocyclic Diamines

Russian Journal of General Chemistry - The reactions of tropylium salts with 2,5-diamino-1,3,4-thiadiazol, 3,5-diamino-1,2,4-thiadiazol, and 2,6-diaminopyridine have given novel products of...     

CYCLIZATION OF ISOMERIC BUTENYL PHENYL SULFIDES ON CHROMIC CATALYSTS

Abstract

It is established that isometric butenyl phenyl sulfides on chromic catalysts yield mainly direct cyclization products unlike their reactions on heterogenous acidic catalysts previously investigated in our laboratory. In the presence of such catalysts the formation of cyclic comcounds proceeds in different ways depending on the position of the side-chain double bond. In case chromic catalysts are used the mentioned factor affects only the easiness of cyclization, but not the nature of the process as such.     

Switching Autowaves in Materials with Dislocations and Martensitic Transformations

Russian Physics Journal - The paper focuses on the investigation of the strain kinetics at the yield point of materials with shear dislocations and martensitic transformations at a microlevel. In...