Dendrimer synthesis convergent

A dendrimer-based approach for the design of globular protein mimics using glutamic (Glu) and aspartic (Asp) acids as building blocks has been developed [151]. The preassembled Glu/Asp dendrones were attached to a 1,3-bifunctional adamantyl based on a convergent dendrimer synthesis strategy (see Fig. 28). 

Conventional sulfur vulcanization cure systems, 21 801 Convention du Mtre, 24 434 Convergent dendrimer synthesis method, 26 787-788... 

The concept of postmodification of the molecule s periphery is thus not only appropriate for the introduction of simple functionalities determining the physical and chemical properties of the molecule (e.g. solubility), but also allows the introduction of complex function-bearing units (e.g. catalytically active units, anti-tumour agents), which could be too sensitive for convergent dendrimer synthesis. 

Scheme 11.10 CpFe+-induced hexabenzylation of CgMeg applied to direct convergent dendrimer synthesis of a 54-allyl dendrimer.

The synthesis of triazole dendrimers starts from 3,5-dichloro-4-(4-methoxyphenyl)-4H-1,2,4-triazole, which can be obtained from methoxy-phenylisocyanate, as shown in Figure 9.4. This substance has an appropriate AB2-symmetry. Therefore, it is well-suited for convergent dendrimer synthesis. The reaction proceeds in the way of a Williamson type ether synthesis. To control the branching, 3,5-bis-(fen-butyl)-phenolis added. ... 

Soon after the introduction of convergent dendrimer synthesis, " hemispherical, aryl-ester-coated, benzyl ether-based dendrons were reported. Attachment to a divalent core and conversion to the polycarboxylate 25 (Fig. 5) yielded dendriiners that facilitated a 200-fold increase in pyrene (26) solubility in water eompared with that of pure water without the dendrimer. Notably, use of sodium dodecyl sulfate (SDS above cmc 9 X 10 M) for pyrene encapsulation resulted in only an 100-fold enhancement. 

FIGURE 4.17 A dendrimer built from three dendrons using the Frdchet approach to convergent dendrimer synthesis. 

Figure 8. Doubly exponential dendrimer synthesis involving simultaneous growth in divergent and convergent directions.

In general, convergent methods produce the most nearly isomolecular dendrimers. This is because the convergent growth process allows purification at each step of the synthesis and therefore no cumulative effects of failed couplings are found [85, 89]. Appropriately purified convergent dendrimers are probably the most precise synthetic macromolecules that exist today. 

The convergent approach to dendrimer synthesis has evolved considerably over the past dozen years. With the benefit of hindsight, it is clear that the key criteria for a successful convergent synthesis include ... 

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

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