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. (C) 2013 Elsevier Ltd. All rights reserved.