Don Cucna synthesizer

In order to make washing resin beads very simple and to solve some of the inherent problems connected with the liquid transfer, we have developed and used two new concepts in our synthesizers. The liquid exchange in the La Marast and Domino Blocks is based on the evacuated reaction vessel concept (1). The Don Cucna synthesizer uses a suction principle for draining reaction vessels and a standard polypropylene 96-well plate as an integrated disposable reaction vessel (2). All synthesizers are commercially available (Torviq, Tucson, AZ, www.torviq.com). 

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... 

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