A nonlocal Hamiltonian formalism for semi-Hamiltonian systems of the hydrodynamic type

A nonlocal Hamiltonian formalism for semi-Hamiltonian systems of the hydrodynamic type is constructed using the formal Baker-Akhiezer functions for a (2+1)-dimensionaln-wave system. Translated from Teoreticheskaya i Matematicheskaya Fizika. Vol. 116, No. 1, pp. 113–121 July, 1998.     

Enantioselective reduction of C=O and C=N bonds by TADDOL-containing aluminum hydride reagents based on NaAlH4 and AlH3

Prochiral substrates (alkyl aryl ketones, cyclopropyl methyl ketone, 1-indanone, 1-tetralone, ethyl 2-oxo-4-phenylbutyrate, and N-(diphenylphosphinyl)acetophenoneimine) were subjected to asymmetric reduction with aluminum hydride reagents, which were prepared by modifications of NaAlH₄ or AlH₃ with chiral ,,","-tetraaryl-1,3-dioxolane-4,5-dimethanols (TADDOL). The effects of the nature of the substituents in TADDOL, the structure of the prochiral substrate, and the reaction conditions on the stereochemistry of reduction were investigated. The highest enantioselectivity (70—90% ee) was achieved upon reduction of alkyl aryl ketones and N-(diphenylphosphinyl)acetophenoneimine with NaAl(TADDOLate)H₂ in THF or diglyme at a temperature from –70 to –20 °C. The mechanism of asymmetric induction in the reduction reactions of ketones with aluminum hydride reagents is discussed. The stereochemical results of reduction were explained by comparing three-dimensional models of the most probable transition states.     

Selective method for the preparation of 5-chloropentan-2-one

A selective method for the preparation of 5-chloropentan-2-one by interaction of 1-methylcyclobutanol with Ca(OCl)₂ followed by decomposition of the hypochlorite thus obtained in the presence of Fe^II salt is proposed. The selectivity of the ketone formation from the alcohol is 98%, while the conversion of the alcohol is 35–40%.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 774–776, April, 1995.     

Physicochemical properties of KOH-H<Subscript>2</Subscript>O<Subscript>2</Subscript>-H<Subscript>2</Subscript>O solutions

Density, viscosity, and surface tension of KOH-H₂O₂-H₂O solutions used to synthesize potassium superoxide in sprayer apparatus were studied with various relative amounts of the components in the temperature range 0–30°C. Analytical dependences of the above-mentioned quantities on temperature and solvent (water) content of the system were found.     

Heat resistance of composite sorption-active materials based on zeolite and fluoroethylene polymers

Relationship was found between the temperature of thermal degradation of composite sorption-active materials based on fluorinated ethylene polymers and the content of NaX zeolite in these materials.     

Asymmetric reduction of acetophenone and propiophenone by NaAl(IPTOLate)H2 combined with enantiomeric enrichment of the reaction product as an inclusion complex with IPTOL

An improved procedure was developed for asymmetric reduction of acetophenone and propiophenone by the chiral reagent NaAl(IPTOLate)H₂. This procedure is based on isolation of the chiral alcohol that formed as a crystalline host—guest complex with the IPTOL ligand. The enantiomeric enrichment of the product was as high as 97% ee. The ability of IPTOL and its analogs to form host—guest complexes with a number of ether-type solvents, 1-phenylethanol, and 1-phenylpropan-1-ol as well as thermal stabilities of IPTOL-containing complexes with these alcohols were studied.     

The properties of water in solutions of hydrophilic polymers

The properties of water in solutions of hydrophilic polymers were compared with those in solutions of their monomeric analogues. The properties of polar groups grafted to polymeric molecules were known to remain unchanged. A comparison of the properties of water in solutions of polymers and the corresponding monomers under equal conditions therefore allowed us to obtain information about the influence of polymeric bonds on the properties of water in solutions of polymers. Proceeding from this, we analyzed the influence of polymeric chains and three-dimensional polymeric network on the activity and concentration of water in solutions of polymers.