Synthesis of Copolymers from Phenylboronic Acid-Installed Cyclic Carbonates

Abstract

Organoboron polymers play important roles in biomedical applications. An ample number of monomers bearing boronic acid derivatives have been synthesized, particularly focusing on controlled free radical polymerization methods. Organoboron polymers synthesized by ring-opening polymerization (ROP) routes are far less explored. We report on the ROP of boronic acid-installed cyclic carbonates, catalyzed by DBU from a poly(ethylene glycol) macroinitiator. Controlled polymerization proceeded to relatively high conversions (∼70%) with low polydispersity. Deprotection of the copolymer to generate the boronic acid pendant group was readily achieved by displacement of the protecting group with free diboronic acid. The resulting amphiphilic copolymers self-assembled in water into spherical nanoparticles or vesicles, depending on hydrophilic/hydrophobic ratio. We envision these functional carbonates finding direct applications for core stabilization of biodegradable amphiphilic assemblies or in drug and protein encapsulation.

Degradable Controlled-Release Polymers and Polymeric Nanoparticles: Mechanisms of Controlling Drug Release

“…Certain polymers respond to ROS through the oxidation of functional groups, such as sulfides, 533,534 or selenides, 535 increasing their solubility in water. Polymers can also undergo physical degradation in response to ROS if they contain oxidizable functionalities such as thioketals, boronic esters, 536–539 or (oligo)prolines. 522,540,541 Both scenarios lead to the disassembly of the micelles fabricated from ROS-responsive polymers and include a mechanism for ROS-triggered payload release.…”

Poly(trimethylene carbonate)-based polymers engineered for biodegradable functional biomaterials

“…Recent efforts entail active drug release upon stimuli, 76,80,158 integration of imaging agents, 159 and targeting properties. 160,161 The last two are relevant to theranostics that allows for therapy and diagnostics at the same time using one delivery vehicle.…”

Postpolymerization Modifications of Alkene‐Functional Polycarbonates for the Development of Advanced Materials Biomaterials

“…[41,42] Carbonates bearing reactive functionalities such as aryl, allyl, halide, and azide moieties provide a route for modification of a material's properties postpolymerization. [43][44][45][46] Whilst the number of pendent functionalities compatible with ROP is not limited to the relatively simple functionalities listed above, [47,48] postpolymerization modification of materials bearing even these simple functionalities can be employed to produce materials bearing a much wider range of functional groups. As a small selection of potential modifications, benzyl-functional polymers may be deprotected by hydrogenolysis to yield alcohol and carboxylic acid functional groups (which may then be further modified themselves, e.g., by esterification), [49][50][51] pendent halide functionalities may undergo reaction with nucleophiles, [46,52,53] alkene groups can be modified to provide a wide range of additional Macromol.…”

“…Whilst the number of pendent functionalities compatible with ROP is not limited to the relatively simple functionalities listed above, postpolymerization modification of materials bearing even these simple functionalities can be employed to produce materials bearing a much wider range of functional groups. As a small selection of potential modifications, benzyl‐functional polymers may be deprotected by hydrogenolysis to yield alcohol and carboxylic acid functional groups (which may then be further modified themselves, e.g., by esterification), pendent halide functionalities may undergo reaction with nucleophiles, alkene groups can be modified to provide a wide range of additional functionalities through Michael addition or radical thiol‐ene coupling reactions, and alkyne and azide‐functional polymers may be modified through copper or strain‐promoted azide‐alkyne click chemistry .…”