Synthesis and characterization of a methacrylic polyelectrolyte capable of reacting with primary amines at room temperature in water

Barruet, Julien; Molle, Romain; Babinot, Julien; Penelle, Jacques

doi:10.1016/j.polymer.2009.03.038

Cited by 2 publications

(1 citation statement)

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“…If appropriately designed, blocked NCOs may also undergo direct displacement reactions with good nucleophiles at ambient temperatures−a process known as chemical deblocking that typically proceeds via an addition−elimination mechanism (Scheme 1b). In one of the few examples of ambient temperature chemical deblocking of isocyanates for polymer postmodification, Penelle et al 34 demonstrated the synthesis of a water-soluble ionic poly(methacrylate) containing pendent isocyanates blocked with sodium 4-hydroxybenzenesulfonate. The electron-withdrawing sulfonate group on the phenol served to activate the blocked adduct toward displacement by an amine; however the modification reaction was slow (requiring 72 h) and the polymer product exhibited poor solubility.…”

Section: ■ Introductionmentioning

confidence: 99%

RAFT Polymerization of “Splitters” and “Cryptos”: Exploiting Azole-N-carboxamides As Blocked Isocyanates for Ambient Temperature Postpolymerization Modification

et al. 2016

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A postpolymerization modification strategy based on ambient temperature nucleophilic chemical deblocking of polymer scaffolds bearing N-heterocycle-blocked isocyanate moieties is reported. Room temperature RAFT polymerization of three azole-N-carboxamide methacrylates, including 3,5-dimethylpyrazole, imidazole, and 1,2,4-triazole derivatives, afforded reactive polymer scaffolds with well-defined molecular weights and narrow dispersities ( Đ < 1.2). Model analogues possessing the same N-heterocycle blocking agents with varied leaving group abilities were synthesized to determine optimal deblocking conditions. The reactivity of the azole-N-carboxamide moieties toward nucleophiles can be tuned simply by varying the structure of the azole blocking agents (reactivity order: pyrazole < imidazole < triazole). DBU-catalyzed reactions of thiols with imidazole- and 1,2,4-triazole-blocked isocyanate scaffolds were shown to occur rapidly and quantitatively under ambient conditions. Differences in reactivity of 1,2,4-triazole- and 3,5-dimethylpyrazole-blocked isocyanate copolymers with various nucleophiles at room temperature facilitated sequential and postpolymerization modification. This strategy advances the utility of blocked isocyanates and promotes the chemistry as a powerful postmodification tool to access multifunctional polymeric materials.

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Section: ■ Introductionmentioning

confidence: 99%