Dendrimer synthesis divergent approach

Dendrimers produced by divergent or convergent methods are nearly perfectly branched with great structural precision. However, the multistep synthesis of dendrimers can be expensive and time consuming. The treelike structure of dendrimers can be approached through a one-step synthetic methodology.31 The step-growth polymerization of ABx-type monomers, particularly AB2, results in a randomly branched macromolecule referred to as hyperbranch polymers. 

In order to investigate dendrimers of a different nature [230], Bradley described the synthesis and transfection efficiency of polyamidourea dendrimers synthesised from isocyanate-containing AB3 monomers [231-234]. The use of this kind of tris-branched building block was addressed to enhance dendrimer synthesis by replacement of the 1,4-addition step typical of PAMAM synthesis and to a rapid increase in terminal functionality. The dendritic structures were synthesised using a divergent, microwave-assisted, solid-phase approach with the dendrimers assembled on polystyrene resin via an acid labile linker (see Fig. 26). In particular, a G3.0 polyamidourea bis-dendron with the peripheral amino groups conjugated to L-lysine residues demonstrated remarkable transfection abilities [234],... 

Scheme 1 Schematic representation of divergent and convergent approaches to dendrimer synthesis...

Fig. 6 Schematic representations of the divergent and the convergent approach for dendrimer synthesis...

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