Solid-phase organic synthesis equipment

Other microwave-assisted parallel processes, for example those involving solid-phase organic synthesis, are discussed in Section 7.1. In the majority of the cases described so far, domestic multimode microwave ovens were used as heating devices, without utilizing specialized reactor equipment. Since reactions in household multimode ovens are notoriously difficult to reproduce due to the lack of temperature and pressure control, pulsed irradiation, uneven electromagnetic field distribution, and the unpredictable formation of hotspots (Section 3.2), in most contemporary published methods dedicated commercially available multimode reactor systems for parallel processing are used. These multivessel rotor systems are described in detail in Section 3.4. 

A method has been developed that enables solid phase organic synthesis to be performed in microtiter wells not equipped with any kind of porous material at the bottom to facilitate the separation of solid resin beads from a solvent. The concept of washing resin beads in the Don Cucna synthesizer was developed by the need for a reliable and fast operational cycle applicable to a hundred reaction vessels at the same time. The simplest compact reaction block for solid phase synthesis is the 96-well plate. The suction (aspirating) principle of the Don Cucna synthesizer is based on the fact that in most solvents used in solid phase synthesis the resin beads settle to the bottom of the wells of the plates. The settling of the resin is relatively fast (tens of seconds). After the resin beads have settled, stainless-steel needles connected to an evacuated waste container are slowly immersed into the wells of a plate (Fig. 8). The needles remove the liquid from above the surface of the resin without disturbing the resin bed. For washing the resin beads in 96-well microtiter plates, two... 

Previously, the synthesis of peptidic materials was seen as a cumbersome and expensive method that lacked the precision of other polymeric synthesis methods [3, 10, 13, 16, 18, 33, 36-38, 63]. Synthesis of peptides has quickly advanced with cheaper methods, larger yield quantities, greater precision, and more adaptive equipment and methodology. There are two main pathways of creating a large number of customized peptide sequences, (a) engineered/recombinant DNA synthesis or (b) synthetic solid phase peptide synthesis (SPPS) [1,13, 18, 20, 33, 36, 39 5, 64, 65]. These methods are preferred to traditional methods because of the yield, automation, and time saved when compared to manual organic synthesis. 

Syntheses on solid phase can, in principle, be performed with standard equipment for organic synthesis. This is, however, only justifiable if large amounts of support are being handled. For small-scale preparations or for the development of solid-phase synthetic methodology, the simplicity of solid-phase synthesis should be fully exploited by conducting experiments in parallel. This requires more systematic planning of the experiments, but will be amply rewarded by the number of results obtained. 

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