A Self-Immolative Polymer

Significance

Self-immolative polymers incorporate triggers which, when cleaved, initiate fragmentation of the polymer into simple subunits. Self-immolative polymer 4 was synthesized by ­polymerization of phenyl carbamate 1 followed by capping of the terminal isocyanate with 4-hydroxy-2-butanone (2) and cleavage of the tert-­butoxy protecting groups with TFA. The trigger formed by 2 can be catalytically removed by the protein bovine serum albumin (BSA, in phosphate-buffered saline, pH 7.4) through β-elimination. This initiates decomposition of the polymer into CO₂ and 4-aminobenzylalcohol 5.