Synthesis of Photolabile Dendrimer Cores

Abstract

Two dendrimer cores, 5 and 12, containing o-nitrobenzyl photolabile moieties have been synthesized from piperonal in five and eight steps, respectively. Methylated core analogs 6 and 13 undergo clean photocleavage as indicated by the evolution of isosbestic points in the UV spectra during photolysis and the observation of degradation products by ¹H NMR. These dendrimer cores serve as precursors to dendrimer-based photodegradable materials.

Key words

dendrimers - o-nitrobenzyl cleavage - photochemistry - photodegradable polymers

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14

Photo- and thermally labile hyperbranched polyesters have been reported by B. Voit et al. 13th Biennial Carl S. Marvel Symposium Tucson AZ March 14-16, 1999.

28

The identity of 14 was verified by comparison to the ¹H NMR spectrum provided by Dr. C. P. Holmes of Affymax Research Institute Palo Alto CA of an authentic sample.