Poly(thiolactone) homo- and copolymers from maleimide thiolactone: synthesis and functionalization

Abstract

We describe the synthesis of a thiolactone-functionalized maleimide (MITla), and its (co)polymerization into poly(thiolactone) homo- and copolymers via controlled or free radical polymerization (CRP or FRP) techniques. Homopolymers were synthesized using FRP whereas MITla was copolymerized with styrene and N-iso-propylacrylamide (NIPAAm) via RAFT. In that way, we were able to combine the properties of a maleimide with the possibility to use the thiolactone side chain functionality in subsequent double modification reactions. Thiolactones are susceptible to nucleophilic ring-opening in the presence of primary amines, releasing a thiol moiety that can be used for conjugate addition (nucleophilic thiol-ene) reactions afterwards. We synthesized and characterized copolymers of different compositions, followed by site-specific double modification reactions with a combination of n-butylamine and methyl acrylate

Study on Post‐Polymerization Modification of Ring‐Opening Metathesis Polymers Involving Pendant Thiolactone Units

“…Based on the above findings, it is clear that no significant ring opening reaction regarding P1 has taken place under the studied conditions. It is worth mentioning that in the study of Rudolph et al, the homopolymer of thiolactone maleimide underwent quantitative and the copolymers of thiolactone maleimide underwent moderate (∼60%) aminolysis reactions in CHCl 3 when 10 equiv of butylamine (per thiolactone) was used. Therefore, when we compare those results with our study it is obvious that the thiolactone group in P1 is much more stable than the thiolactone group in the homo and copolymer of maleimide, under the similar experimental conditions.…”

“…In 2015, Rudolph et al synthesized a versatile monomer namely, maleimide thiolactone that can undergo homo and copolymerization through the radical polymerization. The resulting polymers possessing pendant thiolactone group were in situ reacted with butylamine and methyl acrylate (MA) at room temperature to demonstrate the versatility of maleimide thiolactone group toward the aminolysis and subsequent thiol‐Michael reactions . We envisioned that inspiring by this study, maleimide thiolactone compound could easily be converted to an oxanorbornene compound that can undergo polymerization through the ring‐opening metathesis polymerization (ROMP).…”

“…The resulting polymers possessing pendant thiolactone group were in situ reacted with butylamine and methyl acrylate (MA) at room temperature to demonstrate the versatility of maleimide thiolactone group toward the aminolysis and subsequent thiol-Michael reactions. 25 We envisioned that inspiring by this study, maleimide thiolactone compound could easily be converted to an oxanorbornene compound that can undergo polymerization through the ring-opening metathesis polymerization (ROMP). Therefore, a hetero-functionalized polymer that can be prepared when the resulting ROM polymer is simultaneous exposed to aminolysis and thiol-Michael addition reactions.…”

Coding and decoding libraries of sequence-defined functional copolymers synthesized via photoligation

“…In parallel, strategies involving the consecutive insertion of single monomer units (vinyl or acrylate) based on radical processes started to emerge for the synthesis of sequence-defined polymers3738. Further, notable synthetic strategies towards sequence-defined polymers conducted in bulk include the use of thiolactones394041 and multi-component reactions424344. Concomitant to the development of new synthetic approaches to sequence-defined polymers, selected applications of such molecules are emerging, for example, bio-inspired structures for which high sequence definition is essential4546.…”

Protected thiol strategies in macromolecular design

“…Du Prez and co-workers also investigated the preparation of polymers bearing thiolactones in their side chains [238][239][240][241], which could be considered macromolecular precursors for polythiols. The strong interest in the development of such multi-thiol containing polymers finds its origin in the fact that they are potential substrates for the incorporation of various chemical functionalities.…”