Necklace coding

An alternative method for tracking the chemical history is encoding by spatial address. The identity of each entity is defined by its spatial address. A one-dimensional directed split-and-pool procedure, referred to as necklace coding, has been developed for synthesis carried out on SynPhase Crowns and Lanterns.13 Individual supports are strung on a Teflon thread and the position of a particle on the thread (necklace) encoded the previous chemical history (Fig. 1). A similar concept was later reported by Furka and co-workers14,15 Two-and three-dimensional encoding of the directed split-and-pool synthesis platform has been patented by Selectide Corp.16... 

The algorithm described above is for a three-step combinatorial synthesis. However, the method is not limited to only three-step combinatorial libraries the solid-phase support can be derivatized before the directed split-and-pool synthesis on the Encore synthesizer. The necklace coding can also be a very useful tool during the chemistry development process. 

The Encore synthesizer has been designed to integrate the process of handling of solid-phase particles in combinatorial synthesis. The current version of the synthesizer enables synthesis in batches of up to 960 compounds on SynPhase Lanterns. The Encore synthesizer facilitates the sorting of Lanterns into sequences (necklace coding) and the plating of the Lanterns after completion of the synthesis for final release of compounds from Lanterns. The Encore synthesizer consists of the following five tools. 

The Lantern Licking and Stringing (Lapis) Tool (Fig. 5) is used to secure and pick Lanterns from the Magazine while preserving the sequence of Lanterns in a shaft (necklace coding). Loaded Lapis tools are placed into reaction vessels. The Lapis Tool is made of stainless steel and polyethylene and it is compatible with a wide variety of solvents, reagents, and reaction conditions. 

J. Smith, J. Card, W. Cummings, A. Kaniszai, V. Krchnak, Necklace-coded polymer-supported combinatorial synthesis of 2-arylaminobenzimidazoles. J. Comb. Chem. 1999, 7, 368-370. 

The Encore technique combines three different coding methods sequential position on a necklace for the first combinatorial step, color coding of individual necklaces for the second combinatorial step, and reaction vessel coding to identify the last building block. Accordingly, we termed this technique Encore for Encoding by a (Vecklace, Color, and. Reaction vessel. 

Fig. 13.21. Self-organization of the tobacco virus. The virus consists of an RNA helix (shown as a single file ) contaming about 7000 nucleotides, which is sufficient genetic material to code the production of 5 — 10 proteins (first level of supramolecular self-organization). The RNA strand interacts very effectively with a certain protein (shown as a drop, which is the second level). The protein molecules associate with the RNA strand forming a kind of necklace, and then the system folds (third level) into a rodUke shape typical for this virus. The rods are able to form a crystal (level four, not shown here), which melts after heating but is restored when cooled down.

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