Screening parallel

Spong AD, Vitins G, Guerin S, etal. 2003. Combinatorial arrays and parallel screening for positive electrode discovery. J Power Sources 119 778-783. 

Batchwise operating three-phase reactors are frequently used in the production of fine and specialty chemicals, such as ingredients in drags, perfumes and alimentary products. Large-scale chemical industry, on the other hand, is often used with continuous reactors. As we developed a parallel screening system for catalytic three-phase processes, the first decision concerned the operation mode batchwise or continuous. We decided for a continuous reactor system. Batchwise operated parallel sluny reactors are conunercially available, but it is in many cases difficult to reveal catalyst deactivation from batch experiments. In addition, investigation of the effect of catalyst particle size on the overall activity and product distribution is easier in a continuous device. 

A parallel screening system consisting of six equivalent tube reactors was constructed (10 nun diameter, 50 nun length). The reactor system operates in liquid downflow mode the liquid phase is fed into the reactor by an HPLC pump through... 

Microwave irradiation is used to create hot spots on metal clusters in solution, facilitating catalytic cycles in which these clusters participate. An 8x 12 parallel screening system is built based on this concept, and tested using the Heck reaction as a case study. The spatial reproducibility of this system is examined and the pros and cons of monomode and multimode m/w setups are discussed. 

Birkert O., Tunnemann R., Jung G., Gauglitz G., Label-Free Parallel Screening of Combinatorial Triazine Libraries Using Reflectometric Interference Spectroscopy, Anal Chem 2002 74 834. 

Schemel3.8 Parallel screening and ranking of catalysts for the reduction ofisobutenyl groups.

This should come as no surprise, since the physical behavior of materials is non-linear and unpredictable, especially when materials are formulated or in combination. Two examples will suffice high temperature ceramic superconductors and insulators above their critical temperatures or at non-ideal stoichiometries composite structures may show several times the strength or impact resistance than would be expected from their component materials. Materials discovery will always require a good deal of trial and error, factors that may be mitigated by techniques that permit the simultaneous synthesis of large numbers of materials, followed by rapid or parallel screening for desired properties. 

As it can be seen, the investigations of heterogeneous chiral catalysts started in the late 1950s in Japan and has known a worldwide renaissance in the last few years. Because of a multitude of catalysts discovered and developed in the recent years, combinatorial methods have become an important focus of research in asymmetric catalysis [168,169], In the last few years, efficient techniques have been developed for the high throughput parallel screening of chiral catalysts [170-172], However, parallel screening based on product analysis has potential pitfalls, since the e.s. of a... 

Branca, M.A. Screen Dreams The Promise of Parallel Screening. Pharma DD www.pharmadd.com/archives/ Sept2006/screen dreams.asp, last accessed on 14th February 2007. 

Steindl, T.M., Schuster, D., Laggner, C., Chuang, K., Hoffmann, R.D. and Langer, T. (2007) Parallel Screening and Activity Profiling with HIV Protease Inhibitor Pharmacophore Models. Journal of Chemical Information and Modeling,... 

The parallel screening of drug candidates for their pharmacological activity and for their physicochemical and biopharmaceutical properties has become a major challenge in dmg development and is performed at very early stages... 

Fig. 24 Multi-reactor system for parallel screening of catalytic reactions in SCCO2...

Figure 1.2 Comparison of parallel and hierarchical screening strategies.ln the parallel screen the first three assays are run in parallel followed by a manual decision to reduce the candidate compounds down for the subsequent set of three assays. The use of real-time data QC steps and feedback in the hierarchical approach supports the filtering out of failed compounds prior to submission to the next assay. Both strategies...

As shown in Eq. (4), parallel screening of ligand libraries has allowed us to establish that a closely related peptide-based phosphine ligand promotes the catalytic asymmetric conjugate addition of alkylzincs to nitroalkenes [14]. Not only are the corresponding alkyl nitrones obtained efficiently and in high diaster-eo- and enantioselectivity, appropriate acid workup can deliver the derived ketone directly. 

Scheme 6. Parallel screening of ligand libraries indicates that pyridyl dipeptides can serve as effective ligands for Cu-catalyzed allylic substitution reactions that afford quaternary carbon centers enantioselectively...

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