Regioselective Synthesis of Indene from 3-Aryl Propargylic gem -Dipivalates Catalyzed by N -Heterocyclic Carbene Gold(I) Complexes

International audience1-Aryl-3,3-bis(pivaloyloxy)propynes can be converted in good to high yields into either 1,3-or 1,2-bis(pivaloyloxy)indenes, depending on the N-heterocyclic carbene (NHC) gold(I) hexafluoroantimonate catalyst used. Almost exclusive formation of 1,3-di(oxycarbonyl)indene derivatives was achieved with cationic gold complexes containing the embracing N,N'-1,3-bis(9-butylfluorenyl)benzimidazolylidene ligand (nBu FNHC). The regioselective issue of the reaction was rationalized by the specific spatial distribution of the steric bulk in the nBu FNHC ligand. In contrast, only modest selectivities in favor of 1,2-disubstituted indenes were observed with more classical NHC gold complexes, the best selectivity being then obtained with N,N'-1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazolylidene gold chloride (SIPrAuCl) as precatalyst

Closing the gap between centralized and decentralized compound management approaches.

The demand for organized storage concepts to maintain, collect and distribute compounds has grown not only at pharmaceutical companies, but also at smaller research organizations and academic laboratories where there is the demand to store and retrieve substances systematically. However, budget limitations have prevented these smaller groups from buying costly storage systems offered by specialized commercial vendors. On the other hand, within pharmaceutical companies a need for inexpensive and flexible storage concepts has developed and complements the existing automated archives. For reasons of efficiency, most companies have built centralized facilities holding large collections of internal medicinal chemistry compounds to assist various, globally distributed research programs. This standardization and centralization though is not always ideal for a global organization. Therefore, site specific and localized requirements need to be addressed to ensure quick on site access to compounds without losing the global accessibility to them. In this article, we describe an approach towards a low cost and highly flexible store concept with manual compound stores of variable design addressing local needs, created to complement the existing automated stores. A key component of our implementation is the Compound Store Manager software which is capable of administering the different global stores. The developed backend system and centralized data management facilitates the operation and integration of the stores into an existing store environment

Flexible hydrofoil optimization for the 35th America's Cup with constrained EGO method

This paper investigates the use of constrained surrogate models to solve the multi-design optimization problem of a flexible hy-drofoil. The surrogate-based optimization (EGO) substitutes the complex objective function of the problem by an easily evaluable model, constructed from a limited number of computations at carefully selected design points. Associated with ad-hoc statistical strategies to propose optimum candidates within the estimated feasible domain, EGO enables the resolution of complex optimization problems. In this work, we rely on Gaussian processes (GP) to model the objective function and adopt a probabilistic classification method to treat non-explicit inequality constraints and non-explicit representation of the feasible domain. This procedure is applied to the design of the shape and the elastic characteristics of a hydrofoil equipped with deformable elements providing flexibility to the trailing edge. The optimization concerns the minimization of the hydrofoil drag while ensuring a non-cavitating flow, at selected sailing conditions (boat speed and lifting force). The drag value and cavitation criterion are determined by solving a two-dimensional nonlinear fluid-structure interaction problem, based on a static vortex lattice method with viscous boundary layer equations, for the flow, and a nonlinear elasticity solver for the deformations of the elastic components of the foil. We compare the optimized flexible hydrofoil with a rigid foil geometrically optimized for the same sailing conditions. This comparison highlights the hydrodynamical advantages brought by the flexibility: a reduction of the drag over a large range of boat speeds, less susceptibility to cavitation and a smaller angle of attack tuning range