Reactions high-throughput screening

Felcht reports that the testing of industrial-scale processes can be performed with low expenditure by using micro reactors, since this should result in a faster time to market of the development [137]. He also sees uses for micro reactors at the laboratory scale as a means of high-throughput screening and model examinations such as fast determination of reaction kinetics. 

The best combination turned out to be L5 /A9 (ee = 90% at room temperature and 99% at —78 °C with benzaldehydes and ee = 92-99% with other aldehydes).87 Further improvements were reported later.89 Although only a few dozen reactions were monitored by a JASCO-CD-995 instrument, the CD-based assay is amenable to high-throughput screening of enantioselective catalysts. The chemistry itself lends itself ideally to combinatorial asymmetric metal catalysis, since the principle of asymmetric activation is turning out to be very powerful.89... 

Beilina F, Carpita A, Rossi R (2004) Palladium catalysts for the Suzuki Crosscoupling reaction an overview of recent advances. Synthesis 2419-2440 Bhattacharyya SJ (2000) Polymer-supported reagents and catalysts recent advances in synthetic applications. Comb Chem High Throughput Screening 3 65-92... 

Figure 11.21 Results of high-throughput screening of catalysts in a 384-parallel single-bead reactor in a partial oxidation reaction, (a) Arrangement of inactive and total oxidation catalysts in the reactor, (b) screening results for the conversion of a hydrocarbon at 400°C, 1 mL/min per bead.

One of the established methods for finding hits is high-throughput screening (HTS). This is a powerful method enabling several thousands of compounds per day to be tested. However, there are drawbacks. In many cases the assay for the detection of a hit comprises coupled enzymatic reactions, and a test compound may falsely lead to positive results because of its interference with components of the enzyme cascade. Problems may arise further from the chemical substances that make up the compound depository which are tested in HTS. Especially for companies with historically grown collections of compounds, the quality of the chemicals is an uncontrolled parameter in the sense that it is not always known whether the compounds are still unmodified they may have decomposed, precipitated or formed aggregates (polymers). 

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