Combinatorial chemistry building blocks selection

The selection of building blocks is based on information derived from, for example, computational chemistry, where potential virtual ligand molecules are modeled to fit the receptor-protein binding site. Combinatorial chemistry commences with a scaffold or framework to which additional groups are added to improve the binding affinity. Compounds are prepared and later screened using HTS. In this way, many compounds are tested within a short time frame to speed up drug discovery. 

Figure 3.8 Resin-bound dynamic combinatorial chemistry. Left Dynamic combinatorial building blocks immobihzed on sohd phase resin and in solution are allowed to equilibrate by reversible bond exchange to form a resin-bound dynamic combinatorial hbrary. Center The hbrary is screened against a fluorescently labeled target, and dynamic selection occurs. Right The selected hbrary members binding to the labeled target are easily visuahzed, spatially segregated, and identified.

Additionally, the environmental issue of utilizing waste cellulosic material and waste biomass products should be considered as an alternative green chemistry application to the production of many value added products. The combinatorial utilization of carbohydrate scaffolds based on chiral building block functionalization will also constitute attractive and relatively cheap starting materials. This rich selection of potential approaches, combined with further developments of new procedures and modem reagents, creates an enormous opportunity for the field to be at the frontier for many years to come. 

In summary, epoxides are produced not only as endproducts, but also as intermediates because they are valuable building blocks in synthetic organic chemistry [82-84] (Table 1.3). Until recently, epoxide intermediates were produced by direct oxygen transfer to olefins by a variety of stoichiometric methods. Recently, considerable efforts have been made to conduct the transformations selectively under catalytic conditions. Because epoxides are reactive substances, they can undergo diverse transformations by reactions with acids and bases, and their reactivity has been exploited to form a diverse range of products by so-called click chemistry [85,86], which combines the breadth of combinatorial methods with the precise synthesis of organic chemistry. 

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