Synthesis of polynitrogenated analogues of glucopyranoses from levoglucosan

Polynitrogenated analogues of glucopyranoses were synthesised from levoglucosan. These compounds are useful intermediates for the synthesis of new aminoglycoside mimetics.     

First synthesis of arylpyrrolo- and pyrazolopyrrolizinones as useful agents with potential biological interest

Novel arylpyrrolo- and pyrazolopyrrolizinones were prepared in three or four steps starting from aminoarylpyrrole and pyrazole carboxylates through the cyclisation of a Vilsmeier-Haack intermediate. This synthesis was enhanced by diverse N-protections of the aza-heterocycle and furnish new series with potential biological interest.     

COSEARCH: A Parallel Cooperative Metaheuristic

In order to design a well-balanced metaheuristic for robustness, we propose the COSEARCH approach which manages the cooperation of complementary heuristic methods via an adaptive memory which contains a history of the search already done. In this paper, we present the idiosyncrasies of the COSEARCH approach and its application for solving large scale instances of the quadratic assignment problem (QAP). We propose an original design of the adaptive memory in order to focus on high quality regions of the search and avoid attractive but deceptive areas. For the QAP, we have hybridized three heuristic agents of complementary behaviours: a Tabu Search is used as the main search algorithm, a Genetic Algorithm is in charge of the diversification and a Kick Operator is applied to intensify the search. The evaluations have been executed on large scale network of workstations via a parallel environment which supports fault tolerance and adaptive dynamic scheduling of tasks.     

Diels-Alder chemistry on alkene functionalized films

A substrate-independent method has been devised for ring formation at solid surfaces. This entails the aminolysis reaction of allylamine with maleic anhydride pulsed plasma polymer films to yield terminal alkene groups at the surface. Subsequent exposure to 1,3-cyclohexadiene leads to a Diels-Alder type (4 + 2) cycloaddition reaction to give a mixture of endo- and exo-bicyclo[2.2.2]oct-2-ene rings.     

Dehydrochlorination of monodisperse poly(vinylidene chloride) latex

The objective of the work described in this paper was to produce dispersions of small spherical carbon particles, having particle diameters in the region of 0.1 μm. To this end, the dehydrochlorination of poly(vinylidene chloride) (PVDC) latex particles was attempted. The PVDC latex was prepared by a dispersion polymerization route. Both chemical and thermal dehydrochlorination routes were attempted. Chemical dehydrochlorination, using a variety of base/solvent systems, led to nonporous, spherical black particles of the required size, but which contained only 60% carbon; most of the remainder was oxygen, introduced by nucleophilic substitution reactions. Thermal dehydrochlorination, at 700°C under a nitrogen atmosphere, using a fluidized bed arrangement, on the other hand, led to black particles, having 90% carbon and which retained their sphericity, but which were highly porous. Initial chemical dehydrochlorination, prior to thermal treatment, did not seem to reduce the porosity of the final carbons. Dispersions of the carbon particles in a variety of solvents were readily achieved.