Figure 30 Core template (in box) and representative synthesis of the “natural-product-like” library from the benzyl-derived core and alkyne, amine, and carboxylic acid building blocks. For the core template, R represents either benzyl or phenyl side chains. Figure 31 Examples of soluble polymer supports.

Dendrimers have been suggested for use as soluble polymer supports for combinatorial libraries (Fig. 32) [119]. Separation from reactants is accomplished by methods such as size exclusion chromatography or ultrafiltration, where the larger dendrimer is isolated from the smaller reactants. Dendrimers typically have considerably higher loading (more molecules of product per gram of support) than insoluble polymers, and again there is no need to translate solution-phase procedures for use with dendrimer supports. While it would appear that there are several advantages for the use of dendrimers over insoluble polymer supports, there have been relatively few reports of dendrimer-supported parallel or combinatorial syntheses. Only a few dendrimers are commercially available, and the methods of purification required between steps (size exclusion chromatography or ultrafiltration) have not yet been developed in a readily accessible HT format.