An efficient catalytic system for cyclocarbonylation of terpenes into lactones

Three different kinds of representative monoterpenic alcohol are involved in the palladium‐catalysed cyclocarbonylation reaction. Lactone formation is shown to occur when cyclic ( 1 ), tertiary ( 3 ) and primary allylic alcohol ( 7 ) functions are reacted, in the presence of CO with [HPd(SnCl₃)L₂] as the active catalytic species. Good yields and selectivities can easily be reached for isopulegol ( 1 ), and dihydromyrcenol ( 3 ). However, more modest results are obtained for the functionalization of geraniol into the original lactone ( 9 ). This lactone can be largely favoured by using a basic chelating diphosphine ligand such as 1,4‐bis(diphenylphosphino)butane. Copyright © 2005 John Wiley & Sons, Ltd.     

Relaxations during the postcure of unsaturated polyester networks by ultrasonic wave propagation,dynamic mechanical analysis,and dielectric analysis

Ultrasonic wave propagation, dynamic mechanical analysis, and dielectric analysis were used to monitor relaxation phenomena during the nonisothermal postcure of unsaturated polyester networks. The measurements covered 6 decades of frequency. As a result, the residual reactive groups, immobilized in the glassy state by vitrification during an isothermal cure step, gained molecular mobility, which promoted the formation of additional crosslinks. After the postcure, the reaction was complete, and the maximum achievable glass‐transition temperature was reached. Moreover, the frequency and temperature dependence of the two relaxations, one related to the glass‐transition temperature of the partially cured sample and the other to the glass transition of the fully cured sample, was evaluated. The Williams–Landel–Ferry equation was used to model the frequency dependence of the main α‐relaxation data obtained with the different techniques. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 596–602, 2005     

About well-posed optimization problems for functionals in metric spaces

A necessary and sufficient condition of correctness of extremal problems for lower semicontinuous functionals defined in metric spaces is given.This work was performed under the auspices of the Italian Research Council, Grant No. 115-3083-0-5179.     

Solving generalized equations via homotopies

Global Newton methods for computing solutions of nonlinear systems of equations have recently received a great deal of attention. By using the theory of generalized equations, a homotopy method is proposed to solve problems arising in complementarity and mathematical programming, as well as in variational inequalities. We introduce the concepts of generalized homotopies and regular values, characterize the solution sets of such generalized homotopies and prove, under boundary conditions similar to Smale’s [10], the existence of a homotopy path which contains an odd number of solutions to the problem. We related our homotopy path to the Newton method for generalized equations developed by Josephy [3]. An interpretation of our results for the nonlinear programming problem will be given.     

Theory of oscillation type viscometers IV: A thick disk

The viscous drag exerted by a fluid on an oscillating disk is determined by methods similar to those used in Part III. The present paper differs from Part III in that the boundary layer thickness is assumed here to be small compared with both the thickness and the radius of the disk. An extrapolation of the formulae derived here agree sufficiently well, however, with those derived for the thin disk (boundary layer thickness large compared with the thickness but small compared with the radius) that it is possible to make an interpolation between the present formulae and those of Part III that will permit the evaluation of the drag for arbitrary shape disks provided the boundary layer thickness is small compared with the radius.

---

Zusammenfassung Der Einfluss der Zähigkeitskräfte auf eine in einer Flüssigkeit schwingende Scheibe wird nach den gleichen Methoden wie in Tiel III behandelt. Jedoch wird im Unterschied dazu vorausgesetzt, dass die Grenzschichtdicke klein ist im Verhältnis zur Dicke und zum Radius der Scheibe. Die abgeleiteten Formeln lassen sich mit gutem Ergebnis für die dünne Scheibe extrapolieren (hier ist die Grenzschichtdicke jedoch gross, verglichen mit der Scheibendicke, aber klein gegenüber dem Radius), so dass es möglich ist, zwischen diesen Formeln und denen des Teils III zu interpolieren. Damit wird die Berechnung des Reibungsmomentes für Scheiben unterschiedlichster Form ermöglicht, vorausgesetzt, dass die Grenzschichtdicke klein ist gegenüber dem Radius der Scheibe.

---

---

This research was supported by the United States Air Force through the Air Force Office of Scientific Research of the Air Research and Development Command, under contract No. AF 18 (600) 1548. Reproduction in whole or in part is permitted for any purpose of the United States Government. Part of the work was done while one of the authors (G. F. N.) was being supported by a grant from the Alfred P. Sloan Foundation.     

Study of the stability of gonyautoxins in acidic solution

The gonyautoxin group is the major component in mussels contaminated by paralytic shellfish poison in red tides from the west coast of Spain. This study describes the stability of the gonyautoxins stored at different temperatures in acidic solution. The toxins were extracted from contaminated mussels Mytilus galloprovincialis Lmk and purified through BioRex 70. The stability of the gonyautoxins was analyzed by high-performance liquid chromatography. The experiments demonstrated that gonyautoxin 6 is the most unstable toxin in any condition and at temperatures lower than 4°C there is no important change in the other toxins in the first year of storage. At temperatures higher than 0°C, gonyautoxin 2 and gonyautoxin 3 were the most stable of the gonyautoxin group. The results indicate that, at least without further manipulation, these toxins can be safely stored in acidic conditions at low temperatures.     

The synthesis of naturally occurring 4-alkyl- and 4-alkenyl-γ-lactones using the asymmetric reducing agent B-3-pinanyl-9-borabicyclo[3.3.1]nonane

4-Hydroxy-2-alkynoates of high enantiomeric purity, available from the reduction of the corresponding ketones with $\text{B}$-3-pinanyl-9-BBN, are converted to 4-substituted-γ-lactones found in beetle and deer pheromones.     

Dynamics of the immobilization of anaerobic meshopilic bacteria on a plastic support

Applied Biochemistry and Biotechnology - In this article, a study of the dynamics of the immobilization of mesophilic anaerobic bacteria was conducted. Low-density polyethylene (LDPE) ground to...