Products of the catalytic liquid-phase oxidation of 3-carene

The liquid-phase oxidation of 3-carene in the presence of various catalytic systems has been studied. The possibility has been shown of the directed preparation of 3-carene oxide, of ketones with a carane skeleton and a 7-membered ring, or of aromatic tertiary alcohols.Institute of Physical Organic Chemistry, Academy of Sciences of the Belorussian SSR, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 328–334, May–June, 1991.     

Aminohydroxypropane Esters of Hydroxyethylidenebisphosphonic Acid

Abstract

The 1-hydroxyethylidene-1,1-bisphosphonic acid (HEDP) (I) reacts with epichlorohydrine (II) and aminoepoxypropanes (III) in water. Optimum pH for the esterefication is 6–7. The reaction completes in 20–30 h on 60°C at this pH and leads to the mixture of the original HEDP with the mono- and diesters. The mixture of di-Na salts of HEDP and the monochloroester (IV) in ratio 1:1.7 was precipitated from the reaction solution on using of the epichlorohydrine (II). This mixture was used for synthesis of aminoesters (VI a,b) unavailable by direct reaction of HEDP with corresponding aminoepoxides.     

Thiazolium-Substituted Gem-Bisphosphonates

Abstract

Heterocyclic derivatives of gem-bisphosphonates exhibit various biological activities. We have found that thiazolium substituted bisphosphonic acids can be obtained by two-step synthesis from amino-bisphosphonates (I). Reaction of (I) with isothiocyanates in alkohol in the presence of triethylamine led to corresponding thioureas (II) obtained as natrium or triethylamonium salts [1]. Further treatment of (II) with α-bromoketones give aminothiazoles (III) with a good yield. As a rule only less hindered nitrogen atom is involved into the cyclization with formation of one from two of possible isomers.     

Synthesis of benzo-ortho-thiazines S-oxides by Diels-Alder reaction of N-sulfinylanilines with norbornadiene

From substituted N-sulfinylanilines acting as dienes in the Diels-Alder reaction with norbornadiene S-oxides of benzo-ortho-thiazines were obtained, which were oxidized into the corresponding S,S-dioxides belonging to the class of hybrid thiazinesulfonamide compounds.     

Solvation and microdynamics of uranium(IV) in 2LiF-BeF2 melts according to molecular dynamics calculations

The structural features of solvation and diffusion characteristics of U(IV) ion in model 2LiF-BeF₂ melts (Flibe) at 750–1600 K have been studied by the molecular dynamics simulation method. The diffusion activation energy of U(IV) ion in the 2LiF-BeF₂ melt has been calculated.     

Stability of difference schemes in terms of Riemann invariants for a polytropic gas

The monotonicity and stability of a finite difference scheme with respect to initial data in the supremum norm are analyzed as applied to the polytropic gas equations written in terms of Rie-mann invariants for subsonic flows with 1 < γ < 3. Conditions on the initial and boundary data are obtained under which subsonic flows with no shock waves develop in the medium. The theoretical conclusions are supported by numerical results.     

Magnetic relaxation efficiency of gadolinium(III) and holmium(III) in 1-N-butyl-3-methylimidazolium chloride as probed by 35Cl/37Cl NMR

The magnetic relaxation efficiency of gadolilnium(III) and holmium(III) ions in 1-N-butyl-3-methylimidazolium chloride was investigated by the ³⁵Cl/³⁷Cl NMR method over the temperature range of 298?C393 K.     

Adjustment of the burning rate of a composite propellant with regard to its temperature sensitivity

Systematic multifactor experiments aimed at studying the regularities of the adjustment of the burning rate of composite propellants, especially its temperature sensitivity, were performed. It was established that, in contrast to the pressure dependence of the burning rate, which is largely determined by the properties of the base subsystem of components, its temperature sensitivity is influenced by the flame characteristics as well, more specifically, by the properties of the filler particles dispersed into the gas phase, a slowly burning component.