Reactions of epoxides of the pyran series involving ring expansion. Reaction of 4-methyl-3,4-epoxytetrahydropyran with potassium thiocyanate

The reaction of 4-methyl-3,4-epoxytetrahydropyran with potassium thiocyanate occurs with expansion of the oxirane ring and leads to 6-methyl-8-amino-3,7-dioxa-9-thiabicyclo[4,3,0]nonane, the formation of which has been proven by the fact that products of its acylation by acid chlorides of 2-R-cinchonic acids are obtained, and also by the formation of Mannich bases when it is treated with formaldehyde and secondary amines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1039–1042, August, 1992.     

Influence of Surface Properties on Axisymmetric Oscillations of an Oblate Drop in an Alternating Electric Field

Radiophysics and Quantum Electronics - We consider oscillations of a clamped liquid drop in an alternating electric field. The frequencies and damping rates of the drop eigenmodes are studied as...     

On Semisimple Hopf Algebras of Dimension 2 m

In this paper we classify all nontrivial semisimple Hopf algebras of dimension 2 ^{n +1} with the group of grouplikes isomorphic to _{2 n–1}×₂. Moreover, we extend some results on irreducible representations from groups to semisimple Hopf algebras and prove that certain semisimple Hopf algebras, including the ones classified in this paper, satisfy the generalized power map property.     

Reaction of lithium acetylides with car-3-ene-2,5-dione

The reaction of car-3-ene-2,5-dione (1), an oxidation product of (+)-car-3-ene, with lithium acetylides proceeds stereospecifically, but not regioselectively, to give only mixtures of regioisomeric acetylenic alcohols with thesyn-orientation of the hydroxy group. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 183–185, January, 1998.     

On the order of the antipode of hopf algebras

In this paper we consider a conjecture on the order of the antipode of semisimple Hopf algebras in the Yetter-Drinfeld category and study a related property of the ordinary Hopf algebras. We show that most known examples of finite-dimensional semisimple Hopf algebras satisfy this property.     

Manifestation of side-chain interactions in solution properties of “loose” PI-graft-PMMA molecular brushes

The molecular properties of polymer brushes composed of polyimide with polymerization degree 50 and loosely grafted poly(methyl methacrylate) chains of variable length (PI-graft-PMMA) were studied by viscometry, dynamic light scattering, and equilibrium electro-optical Kerr effect methods in a diluted solution. It was established that the intrinsic viscosity and hydrodynamic dimension of PI-graft-PMMA copolymers increase when the electro-optical Kerr constant decreases with the elongation of PMMA side chains in the range of 40–110 monomer units. The observed difference in the solution properties of the copolymers was explained by their side-chain interactions in spite of a large distance between the neighboring grafting points typical of “loose brushes.” A strong effect of the chain rigidity and dipole structure on solution properties of the studied samples was demonstrated. The Kuhn segment lengths for PI-graft-PMMA copolymers were estimated to vary in the range 3.8–12.1?nm.     

Synthesis of Platinum(II) Phoshine Isocyanide Complexes and Study of Their Stability in Isomerization and Ligand Disproportionation Reactions

Russian Journal of General Chemistry - Phosphine isocyanide complexes cis-[PtCl2(CNMes)(P)] with mesitylisocyanide and phoshine ligands were synthesized in yields of 92?98%. The products were...     

Synthesis and morphology of polycaprolactone–block-polyimide–block-polycaprolactone triblock copolymers for film separation membranes

Triblock copolymers with the central polyimide block and peripheral polycaprolactone blocks were synthesized by controlled ring-opening anionic coordination polymerization of ε-caprolactone on polyimide macroinitiators with terminal hydroxy groups. The chemical structure of the products was determined by spectroscopic methods, and the molecular-mass characteristics of the triblock copolymers and their separate blocks were determined by size-exclusion chromatography. Examination of the phase morphology of strong self-supporting films formed from the copolymer solutions revealed microphase segregation on the nanometer level in the films.     

On Semisimple Hopf Algebras of Dimension 2<Superscript><Emphasis Type="Italic">m</Emphasis></Superscript>, II

In this paper we classify, up to equivalence, all semisimple nontrivial Hopf algebras of dimension 2²ⁿ⁺¹ for n ≥ 2 over an algebraically closed field of characteristic 0 with the group of group-like elements isomorphic to \(\mathbb {Z}_{2^{n}}\times \mathbb {Z}_{2^{n}}\). Moreover we classify all such nonisomorphic Hopf algebras of dimension 32 and show that they are not twist-equivalent to each other. More generally, given an abelian group of order 2 ^m?1 we give an upper bound for the number of nonisomorphic nontrivial Hopf algebras of dimension 2 ^m which have this group as their group of group-like elements.     

Chromatographic Analysis of Structural Elements of Molecular Polyimide Brushes with Polymethacrylate Side Chains

The method of thin-layer chromatography under critical conditions was used for the analysis of the functional and structural inhomogeneities of polymethylmethacrylate and poly-tert-butylmethacrylate side chains cleaved from molecular polyimide brushes. Acetic acid–containing mobile phases are suggested, allowing a gradual transition from adsorption to exclusion chromatographic regime to be observed upon variation of the mobile phase composition for both cleaved side chains and “reference” polymethylmethacrylate and poly-tert-butylmethacrylate linear polymers. The presence of a few kinds of cleaved side chains having one terminal carboxylic group and differing in the nature of the other terminal group is revealed.