Synthesis of Nitro,Amino, and Halo Derivatives of 2-Ethyl-2-methyl-2,3-dihydro-1H-indole

Russian Journal of Organic Chemistry - The nitration, oxidative halogenation, and radical bromination and chlorination of 2-ethyl-2-methyl-2,3-dihydro-1H-indole afforded the corresponding nitro,...     

Commutativity of the centralizer of a subalgebra in a universal enveloping algebra

Let G be a reductive algebraic group over an algebraically closed field of characteristic zero, and let \(\mathfrak{h}\) be an algebraic subalgebra of the tangent Lie algebra \(\mathfrak{g}\) of G. We find all subalgebras \(\mathfrak{h}\) that have no nontrivial characters and whose centralizers \(\mathfrak{U}(\mathfrak{g})^\mathfrak{h} \) and \(P(\mathfrak{g})^\mathfrak{h} \) in the universal enveloping algebra \(\mathfrak{U}(\mathfrak{g})\) and in the associated graded algebra \(P(\mathfrak{g})\), respectively, are commutative. For all these subalgebras, we prove that \(\mathfrak{U}(\mathfrak{g})^\mathfrak{h} = \mathfrak{U}(\mathfrak{h})^\mathfrak{h} \otimes \mathfrak{U}(\mathfrak{g})^\mathfrak{g} \) and \(P(\mathfrak{g})^\mathfrak{h} = P(\mathfrak{h})^\mathfrak{h} \otimes P(\mathfrak{g})^\mathfrak{g} \). Furthermore, we obtain a criterion for the commutativity of \(\mathfrak{U}(\mathfrak{g})^\mathfrak{h} \) in terms of representation theory.     

Stereoselective synthesis of natural (2E,4E)-dienamides and their synthetic analogs

A procedure has been developed for stereoselective synthesis of a number of naturally occurring (2E,4E)-dienamides and their analogs via palladium-catalyzed reaction of (1E)-1-iodoalk-1-enes with acrylamides.     

Smoothness of Stationary Subdivision on Irregular Meshes

We derive necessary and sufficient conditions for tangent plane and C ^k -continuity of stationary subdivision schemes near extraordinary vertices. Our criteria generalize most previously known conditions. We introduce a new approach to analysis of subdivision surfaces based on the idea of the universal surface . Any subdivision surface can be locally represented as a projection of the universal surface, which is uniquely defined by the subdivision scheme. This approach provides us with a more intuitive geometric understanding of subdivision near extraordinary vertices. February 16, 1998. Date revised: January 27, 1999. Date accepted: April 2, 1999.     

Synthesis of D,L-Lactide–ε-Caprolactone Copolymers and Preparation of Films Based on Them

D,L-Lactide–ε-caprolactone copolymers were synthesized by polymerization in the bulk. Films of these copolymers were prepared, and their strain properties and degradation rate under physiological conditions were studied. Introduction of ε-caprolactone into the copolymer increases the film elasticity and decreases the degradation rate compared to poly(D,L-lactide) homopolymer, and also favors spreading of human keratinocytes. The films obtained can be used for treatment of wounds and burns.     

Displacement of Silicone Oils from the Hydrophobic Surface by Aqueous Trisiloxane Solutions

Kinetics of the displacement of silicone oils of different viscosity by the aqueous solution of trisiloxane from quartz capillaries from 4 to 7 m in radius with the hydrophobized (methylated) surface is investigated. The displacement kinetics is described by Washburn's equation with the dynamic values of contact angles and bulk viscosities of the solution and oils. In the case of displacing (by the solution) thin oil films, which were preliminarily deposited onto the capillary surface, the advancing meniscus of the trisiloxane solution collects the column of oil from the film. The volume of the collected oil practically coincides with that of preliminarily deposited film, which is indicative of the sufficient extent of displacement. The film displacement rate is controlled by the surface diffusion of trisiloxane molecules over the hydrophobic surface under the oil film. The order of magnitude of the measured surface diffusion coefficients is equal to about 10^–5cm²s^–1.     

Charge reversal at the air/water interface as inferred from the thickness of foam films

Experiments are reported with foam films from aqueous solutions with increasing concentration of a cationic surfactant. A correlation is established between the foam film thickness and the possible variation of diffuse electric layer potential at the air/water interface from a negative value in absence of surfactant to positive values at higher surfactant concentrations. It is concluded that a charge reversal at the air/water interface is expected to occur under increasing concentration of cationic surfactants in aqueous solutions.     

Synthesis,structure, and properties of 1,3-oxazacycloalkanes (review)

Research dealing with methods for the synthesis of 1,3-oxazacycloalkanes and their structures and homolytic and heterolytic transformations is reviewed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 435–449, April, 1982.