Combinatorial chemistry Reaction screening

Chemical activities in the field of mass screening are often related to combinatorial chemistry [51,52]. One major goal, especially in the field of solid phase chemistry involving polymers like DNA or peptides, aims at the increase in the number of compounds per reactor volume and time. Commercially available microtiter plates are established as reactors in this case whereby robotic feed systems fit perfectly to their dimensions. A drastic reduction of reaction volume and increase in number of reaction vessels ( wells ) leads to the so-called nanotiter plates (e.g. with 3456 wells). Microfabrication methods such as the LIGA process are ideal means for the cost effective fabrication of nano-titer plates in polymeric materials by embossing or injection molding techniques so that inexpensive one-way tools are realized. 

The newly available biological high-throughput screening (HTS) systems have induced many initiatives in the field of combinatorial chemistry [42]. Besides oligopeptide syntheses [43], multicomponent reactions offer attractive methods for the production of high-diversity libraries. Passerini and Ugi reactions (Scheme 19) are frequently used for synthesis of libraries containing thousands of compounds [44],... 

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