Parallel synthesis polypropylene reactor

Recently, Murray and Gellman demonstrated that parallel synthesis in inexpensive 96-well polypropylene filter plates with microwave irradiation in a multimode reactor is a simple and effective method for the rapid preparation of j8-peptide hbraries on sohd support in acceptable purities [156]. 

Microwave-assisted reactions allow rapid product generation in high yield under uniform conditions. Therefore, they should be ideally suited for parallel synthesis applications. The first example of parallel reactions carried out under microwave irradiation conditions involved the nucleophilic substitution of an alkyl iodide with 60 diverse piperidine or piperazine derivatives (Scheme 4.22) [76]. Reactions were carried out in a multimode microwave reactor in individual sealed polypropylene vials using acetonitrile as solvent. Screening of the resulting 2-aminothiazole library in a herpes simplex virus-1 (HSV-1) assay led to three confirmed hits, demonstrating the potential of this method for rapid lead optimization. 

A recent article describes the construction and use of a parallel polypropylene reactor comprising of cylindrical, expandable reaction vessels with porous frits at the bottom (Fig. 7.4)21. This is the first description of reaction vessels for microwave-assisted synthesis that may be useful for carrying out solid-phase synthesis using bottom filtration techniques in conjunction with microwave heating. However, at the time when tins chapter was being written no application of this system for solid-phase synthesis had been reported. 

The explosion of combinatorial chemistry in the nineties triggered the constmction of a variety of reaction blocks for multiple parallel synthesis. Some of them are still in production, including the MiniBlock developed by Bohdan, Inc. (now part of Mettler-Toledo, www.mt.com/autochem) and Solid-Phase Synthesis Reaction blocks by J-KEM (www.jkem.com). The Bohdan MiniBlock reactor can hold up to 48 disposable polypropylene-fritted tubes in a 48-well format (6x8 array) and accommodates IRORI s MicroKans. The MiniBlock can be equipped with accessories for synthesis under inert atmosphere or at elevated temperatures. 

MultiBlock. In the late eighties, Krchnak and Vagner designed the MultiBlock, the first reaction block for parallel solid-phase synthesis (Figm-e 3.19). The MultiBlock consists of five parts (i) a Teflon block that holds 42 reactors, polypropylene syringes equipped with a plastic (ii) a vacuum adapter that connects each reactor to a vacuum line and allows... 

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