A new poly(propylene imine) dendron as potential convenient building-block in the construction of multifunctional systems

The synthesis of a novel third generation poly(propylene imine) dendron (PPI dendron) is described herein. The dendritic focal point was attached to a tetraethylene glycol spacer that was terminated with a Tmob-protected thiol in order to both avoid any side-reaction during functionalization of dendritic branches as well as enable convenient integration of the dendron into diverse complex systems. The protonation of the final PPI dendron at pH 4–5 is predicted to induce lysosomal degradation through the proton-sponge effect, and therefore enable cytosolic release. These features make the prepared dendron a very convenient building-block for use in the construction of larger systems, such as multifunctional drug delivery vehicles.