Catalytic oxidation of octene-1 in the presence of palladium(II) salts and heteropolyacids

In the presence of the catalytic system (PdSO₄+HPA), where HPA=H₉PMo₆V₆O₄₀, octene-1 is found to be selectively (95%) oxidized to octanone-2. The optimum concentration ratio for catalyst stability is [HPA]:[PdSO₄]=30–40. The substitution of PdCl₂ for PdSO₄ leads to the formation of all three isomeric octanones without decrease of the overall selectivity. Effective rate constants and the apparent activation energy have been determined in the temperature range from 60 to 80 °C.

---

(PdSO₄+), =H₉PMo₆V₆O₄₀, -1 ( 95%) -2. []:[PdSO₄]=30–40. PdSO₄ PdCl₂ . 60–80 °C.

     

Cross-metathesis reaction of vinyl sulfones and sulfoxides

Cross-metathesis reactions of α,β-unsaturated sulfones and sulfoxides in the presence of molybdenum and ruthenium pre-catalysts were tested. A selective metahesis reaction was achieved between functionalized terminal olefins and vinyl sulfones by using the ‘second generation’ ruthenium catalysts 1c-h while the highly active Schrock catalyst 1b was found to be functional group incompatible with vinyl sulfones. The cross-metathesis products were isolated in good yields with an excellent (E)-selectivity. Both the molybdenum and ruthenium-based complexes were, however, incompatible with α,β- and β,γ-unsaturated sulfoxides.     

The Tricyclooctanone Approach to the Total Synthesis of Steroids. The Cyclization of the A-CD Unit

The first steps of a novel approach to the total synthesis of 9, 11-dehydroestrone via tricyclo[3.3.0.0^2,8]octan-3-one (2) are described. One route involves a tandem-type transformation of the key intermediate 3 (A-CD unit) consisting of cyclopropane cleavage and ring B closure to afford C, 18-bisnor-13 α, 17 α-estradiol derivatives. E.g. the 3-methoxy-9 ζ-hydroxy-17 α-methanesulfonyloxy derivative (-)- 6 has been synthesized in 8 steps and 10% overall yield from 1,3-cyclohexadiene. As an alternative, the A-CD type intermediate 4b has been prepared and could be used for a ring C enlargement prior to cyclization.     

Differential-difference evolution equations. II (Darboux transformation for the Toda lattice)

Toda lattice equation is represented in the form of the condition of compatibility of the system of linear equations corresponding to a non-Hermitian Lax representation. The Darboux invariance of this linear system is defined and proved in the text, and enables us to construct some new formulas for the solutions of the Toda lattice equation. These formulas involving determinants are applicable to an arbitrary initial solution of the Toda equation for example to a solution growing at infinity.Physique Mathématique et Théorique, Equipe de recherche associée au CNRS.This work has been done as part of the program Recherche Cooperative sur Programme No. 264: Etude interdisciplinaire des problèmes inverses.Leningrad State University, U.S.S.R.     

A finite volume cell‐centered Lagrangian hydrodynamics approach for solids in general unstructured grids

A finite volume cell‐centered Lagrangian hydrodynamics approach, formulated in Cartesian frame, is presented for solving elasto‐plastic response of solids in general unstructured grids. Because solid materials can sustain significant shear deformation, evolution equations for stress and strain fields are solved in addition to mass, momentum, and energy conservation laws. The total stress is split into deviatoric shear stress and dilatational components. The dilatational response of the material is modeled using the Mie‐Grüneisen equation of state. A predicted trial elastic deviatoric stress state is evolved assuming a pure elastic deformation in accordance with the hypo‐elastic stress‐strain relation. The evolution equations are advanced in time by constructing vertex velocity and corner traction force vectors using multi‐dimensional Riemann solutions erected at mesh vertices. Conservation of momentum and total energy along with the increase in entropy principle are invoked for computing these quantities at the vertices. Final state of deviatoric stress is effected via radial return algorithm based on the J‐2 von Mises yield condition. The scheme presented in this work is second‐order accurate both in space and time. The suitability of the scheme is evinced by solving one‐ and two‐dimensional benchmark problems both in structured grids and in unstructured grids with polygonal cells. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis of chlorophyll a glycoconjugates using olefin cross-metathesis

Chlorophyll a glycoconjugates were obtained by cross-metathesis between olefin moieties of chlorophyll derivatives and allylβ-galactopyranoside tetraacetate.