Highly Selective Mitsunobu Esterification of Cellulose with Hydroxycinnamic Acids. Issue 21 (10th October 2021)

• Record Type: Journal Article
• Authors: Elschner, Thomas; Brendler, Erica; Fischer, Steffen
• Is Part Of: Macromolecular chemistry and physics. Volume 222:Issue 21(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-10
• Subjects: cellulose -- ferulic acid -- hydroxycinnamate -- Mitsunobu reaction -- selective esterification; Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.202100232
• Languages: English
• ISSNs: 1022-1352

Abstract

Abstract: Cellulose esters of hydroxycinnamic acids, namely ferulic‐, p ‐coumaric‐, and caffeic acid, are synthesized by Mitsunobu esterification applying triphenylphosphine and diisopropyl azodicarboxylate in N, N ‐dimethylacetamide/LiCl. The reaction is found to be highly selective and took place at primary hydroxyl groups at position 6 of cellulose without undesired conversion of double bonds and phenolic hydroxyl groups. Molecular structure characterization is performed by FTIR‐ and NMR spectroscopy. The products are soluble in dimethyl sulfoxide and possessed degree of substitution (DS) values of up to 0.5. DS values are determined by two independent methods, namely 1 H NMR spectroscopy of peracetylated derivatives and UV spectroscopy of extracted ferulic acid. The synthesis of cellulose hydroxycinnamates is very important to design lignocellulosic model systems and antioxidative bioinspired materials. Abstract : Mitsunobu esterification allows one‐step conversion of cellulose with hydroxycinnamic acids to tailor bioinspired materials. High selectivity known from advanced organic chemistry is exploited in cellulose chemistry to save additional steps. Reaction takes place preferably at primary position 6 of cellulose. The approach is suited for carboxylic acids with sensitive double bonds and phenolic hydroxyl groups.