Complete Parallel-synthesis Apparatus

These are total systems or even plants made for parallel automated organic synthesis, typically in the liquid phase. In this section, no commercial devices (typically not relying on micro flow processing) are considered, but rather only specialty apparatus developed in the framework of chemical micro processing. 

Whereas commercial systems usually employ stirred mini vessels, laboratory-developed apparatus may be operated in flow-through mode. For mini-vessels (vials, wells), the titer plate format is typical and widely accepted. 

Reactor 36 [R 36] Solid-phase Synthesis-Pneumatic Agitation-8-Reactor System 

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The split-and-mix strategy appears deceptively similar to parallel synthesis, but can produce libraries of several hundred thousand compounds in one mn. Although it can use the same style of apparatus as for parallel synthesis, there would normally be as many synthesis channels as one has monomers - 20 in the case of natural amino acids (although cysteine is often omitted). However, after the first coupling cycle has been completed, the batches of synthesis beads from each channel would all be combined, mixed well, and re-divided back into the 20 synthesis channels - the step from which the method takes its name. After this, another round of chain extension would commence. In this way all possible sequences are prepared at the same time, but each bead of solid support only contains one sequence. As the number of compounds rises exponentially with each chain extension cycle (hence it is combinatorial), large numbers of monomers limit the number of cycles that can be performed - usually to four rounds (i.e. a tetrapeptide library) with 20 different monomers, = 20" =160 000 compounds. This is because the number of possible sequences should be significantly less than the number of synthesis beads that can be contained in a reasonable volume. 

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