Synthesis of multiple stimuli-responsive degradable block copolymers via facile carbonyl imidazole-induced postpolymerization modification

Abstract

A robust approach that centers on carbonyl imidazole chemistry was used to synthesize a triple-stimuli-responsive degradable block copolymer labeled with acetal, disulfide, and o-nitrobenzyl groups exhibiting acid, reduction, and light responses.

Synthesis and Dual-Acid/Light-Responsive Disassembly of Amphiphilic Block Copolymer Nanoassemblies Bearing Conjugated Benzoic Imine Pendants

“…Given unsuccess with direct RAFT polymerization for M2 bearing conjugated benzoic imine, a postpolymerization modification method was explored. CDI-mediated coupling reaction has been known to be facile and quantitative under mild conditions. , Figure illustrates our approach utilizing a combination of RAFT polymerization with CDI-mediated coupling reaction with an OH-bearing conjugated benzoic imine precursor.…”

“…CDImediated coupling reaction has been known to be facile and quantitative under mild conditions. 28,37 Figure 4 illustrates our approach utilizing a combination of RAFT polymerization with CDI-mediated coupling reaction with an OH-bearing conjugated benzoic imine precursor.…”

“…27 Recently, triple pH/glutathione/ light-responsive triblock copolymer micelles were designed with both acetal and disulfide on the backbone in the center of the copolymer and o-nitrobenzyl pendants in the hydrophobic block. 28 Benzoic imine is one of the Schiff bases that is formed by the reaction of an aldehyde and a primary amine. It undergoes acid-catalyzed hydrolysis, resulting in the cleavage of C�N double bond to generate the corresponding aldehyde and amine.…”

“…Dual pH/light-responsive crosslinked micelles were fabricated by self-assembly of amphiphilic glycol chitosan- o -nitrobenzyl succinate conjugates, followed by crosslinking with glutaraldehyde through the formation of imine (acid-responsive) linkage . Recently, triple pH/glutathione/light-responsive triblock copolymer micelles were designed with both acetal and disulfide on the backbone in the center of the copolymer and o -nitrobenzyl pendants in the hydrophobic block …”

C−H Functionalization and Allylic Amination for Post‐Polymerization Modification of Polynorbornenes

“…[14][15][16][17] When surveying PPM methods, one might categorize known approaches as those that either rely on a discretely activated functional group in the monomer or repeat unit, in comparison to those that require activation of otherwise nominally unreactive commodity polymers. Examples of the former include polymerization of acrylates bearing activated ester moieties, primed for acyl substitution postpolymerization, [18][19][20] as well as use of monomers bearing any of a number of "clickable" functional handles that enable efficient post-polymerization coupling reactions. [21][22][23][24] Although effective, methods that rely on specialty monomers to facilitate PPM often bear the burden of increased cost, sensitivities to moisture, or poor polymerization reactivities.…”