Organic carboxylate salt-enabled alternative synthetic routes for bio-functional cyclic carbonates and aliphatic polycarbonates

• Published in: Polymer chemistry 2022-09, Vol.13 (36), p.5193-5199
• Main Authors: Watanabe, Yuya, Takaoka, Shunya, Haga, Yuta, Kishi, Kohei, Hakozaki, Shunta, Narumi, Atsushi, Kato, Takashi, Tanaka, Masaru, Fukushima, Kazuki
• Format: Article
• Language: English
• Subjects: Aliphatic compounds; Biodegradability; Biomedical materials; Bromides; Carbonates; Carbonyls; Esterification; Polycarbonate resins; Polymer chemistry; Propionic acid; Ring opening polymerization
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/d2py00705c

Simple and efficient synthetic routes for functionalized cyclic carbonates are indispensable for the practical application of side-chain bio-functionalized aliphatic polycarbonates as biodegradable functional biomaterials. In this study, a six-membered cyclic carbonate with a triethylammonium carboxylate has been prepared in one step from 2,2-bis(methylol)propionic acid (bis-MPA). We have demonstrated the suitability of the organic carboxylate salt of the bis-MPA cyclic carbonate for esterification with alkyl bromides via the S N 2 mechanism, leading to the formation of functionalized cyclic carbonate monomers. The esterification of the organic carboxylate salt proceeds efficiently when alkyl bromides with α-carbonyl, allyl, and benzyl groups are used. This approach enables a two-step synthesis of functionalized cyclic carbonates from bis-MPA. The organocatalyzed ring-opening polymerization of the resultant functionalized cyclic carbonates is effectively controlled, indicating that the synthetic process involving the organic carboxylate salt does not influence their polymerizability. The ether-functionalized aliphatic polycarbonates obtained from the organic carboxylate salt exhibit good antiplatelet properties, comparable to those of a previously developed blood-compatible aliphatic polycarbonate. The synthetic pathways exploiting organic carboxylate salts enable alternative shortcuts to functionalized cyclic carbonates from bis-MPA. A cyclic carbonate with an ammonium carboxylate residue was found to serve as a nucleophile for esterification with alkyl bromides via the S N 2 mechanism.