Threefold Metal-free Efficient ("Click") Reactions onto a Multifunctional Poly(2-oxazoline) Designer Scaffold
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Kempe, Kristian; Hoogenboom, Richard; Jäger, Michael; Schubert, Ulrich S.
- Abstract:
- The synthesis of a new multifunctional copoly(2-
oxazoline) scaffold containing a-anthracene and ω-azide termini as
well as pendant alkene groups in the side chain is described. With its
three different functionalities this system represents the first polymer
scaffold that can be applied in triple orthogonal (“click”) postmodification
reactions. Thus, the functional groups were exploited
for sequential 3-fold metal-free efficient reactions encompassing
DielsAlder cycloaddition (DA), thiolene coupling (TE) and
strain-promoted azide alkyne cycloaddition (SPAAC) reactions.
Each reaction was optimized individually to determine the preferential
reaction order for the sequential three-step functionalization
of the polymer scaffold: SPAACDATE. The successful progress
of the successive reactions was confirmed by 1H NMR spectroscopy,
MALDITOF MS spectrometry, (online) infrared spectroscopy and UVVis spectroscopy, respectively. Furthermore, a onepot
three-step reaction for the 3-fold modification of the polymer scaffold is reported. Finally, the potential of the triple postmodifications
for the preparation of functional nanoparticles by nanoprecipitation is presented using various functional groups to
tune the overall solubility of the copolymer, to attach cell penetrating or targeting groups and to prepare labeled systems
demonstrating the versatility of this approach for the preparation of multifunctional nanoparticles.
- Year:
- 2011
- Type of Publication:
- Article
- Journal:
- Macromolecules
- Volume:
- 44
- Pages:
- 6424 - 6432