Directed sorting approach

Directed Sorting Approach for the Synthesis of Large Combinatorial Libraries of Discrete Compounds... 

The directed sorting approach (or mix-and-sort approach) uses small synthetic objects, usually called microreactors, which are equipped with a readable encoding system. Typically the synthetic objects can be resin... 

A system based on grafted polymer synthetic objects (lanterns) is available from Mimotopes Pyt. Ltd.12 The system is composed of the synthetic objects (lanterns), RF-Tags (Transtems), software to track the synthesis (TranSort), and a cleavage system. Additional systems that are not commercially available have been reported. Workers at Aventis have developed a highly automated system based on the Mimotope lanterns.13 Recently workers at Millenium Pharmaceuticals reported the St AC system (Stratified Adressable System), a three-dimensional spatial array that allows discrete compounds to be synthesized using the same efficiency as the directed sorting approach.14... 

The directed sorting approach has been widely applied both in industry and in academia. Two examples are detailed in this chapter. Some other recently published examples include a benzopyran library synthesized using the Nanokan system,15 libraries derived from phenolic amino acid scaffolds prepared with the Accutag system,16 and libraries of l,5-benzodiazepine-2-one derivatives.17... 

The directed sorting approach is a convenient technology to produce large combinatorial libraries of discrete compounds. As can be seen with the two examples presented, it is a very versatile and practical method to produce compounds in a variety of formats. 

The first step in recycling plastics is to sort the plastics by their resin type, or resin identification code. The resin identification code is a number assigned to a plastic product (or container) according to the type of polymers it is made of. While it was once common to directly use this code to identify the types of polymer(s) present, there are now other methods, such as near-infrared spectroscopy or density sorting approaches, that are used to sort mass quantities of plastic samples for recycling. (See Polymer Chemistry for more information on resin identification codes.)... 

Early comparisons of this sort were based on work by Handy and coworkers [37], who developed an efficient direct FCI approach in terms of determinants. Using a double-zeta (DZ) basis set, they considered stretching the 0-H bond lengths in the H2O molecule to 1.5 and 2.0 times their equilibrium values. The FCI results showed that even the restricted Hartree-Fock (RHF) based fourth-order many-body perturbation theory (MBPT) approach [38], which includes the effect of single, double, triple and quadruple excitations, did not accurately describe the stretching of the bond the error increased from 0.6 kcal/mole at to 10.3 kcal/mole... 

Combinatorial syntheses can be performed in two ways (i) split-and-pool (also referred to as the split-and-mix or the split-and-recombine method)and its variant directed sorting" and (ii) parallel synthesis. A hybrid approach is the split-and-split technique. " ... 

If it is assumed that precursors can be identified in a scientific way, the next research question can be formulated. By using only precursors the elimination of all possible accidents is extremely unlikely. Retrieving precursors and acting upon them can be seen as a sort of fire fighting approach. It is more important to devise pro-active measures to discover the underlying factors, causing the possible accidents. Subsequently companies can direct resources at these identified causal factors and possible accidents can actually be prevented. The next research question is therefore formulated as ... 

What can be done if there is not an exact literature precedent for the required enzymatic transformation In these cases some sort of screening procedure may be necessary, either by direct screening of commercial enzymes, culture collections and environmental isolates, or by using a bioinformatics-based approach to identify potential enzymes based on sequence information. 

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