The Importance of Reaction Conditions on the Chemical Structure of N , O -Acylated Chitosan Derivatives

• Published in: Molecules (Basel, Switzerland) Vol. 24; no. 17; p. 3047
• Main Authors: Piegat, Agnieszka, Goszczyńska, Agata, Idzik, Tomasz, Niemczyk, Agata
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 22-08-2019; MDPI
• Subjects: Acylation; acylation reaction; Amino groups; Antibacterial activity; Antioxidants; Biocompatibility; Biomedical materials; Chemical modification; Chitosan; Chitosan - analogs & derivatives; Chitosan - chemistry; chitosan derivatives; Deoxycholic acid; EDC/NHS coupling system; fatty acids; Functional groups; Fungicides; Magnetic Resonance Spectroscopy; Molecular Structure; Molecular Weight; Organic chemistry; Polymers; Protonation; Solutions; spectroscopic methods; Spectrum Analysis; Water treatment; EDC/NHS coupling system; acylation reaction; chitosan derivatives; spectroscopic methods; fatty acids
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules24173047

The structure of acylated chitosan derivatives strongly determines the properties of obtained products, influencing their hydrodynamic properties and thereby their solubility or self-assembly susceptibility. In the present work, the significance of slight changes in acylation conditions on the structure and properties of the products is discussed. A series of chitosan-acylated derivatives was synthesized by varying reaction conditions in a two-step process. As reaction media, two diluted acid solutions-i.e., acetic acid and hydrochloric acid)-and two coupling systems-i.e., 1-ethyl-3-(3-dimethyl-aminopropyl)-1-carbodiimide hydrochloride (EDC) and
-hydroxysulfosuccinimide (EDC/NHS)-were used. The chemical structure of the derivatives was studied in detail by means of two spectroscopic methods, namely infrared and nuclear magnetic resonance spectroscopy, in order to analyze the preference of the systems towards
- or
-acylation reactions, depending on the synthesis conditions used. The results obtained from advanced
H-
C HMQC spectra emphasized the challenge of achieving a selective acylation reaction path. Additionally, the study of the molecular weight and solution behavior of the derivatives revealed that even slight changes in their chemical structure have an important influence on their final properties. Therefore, an exact knowledge of the obtained structure of derivatives is essential to achieve reaction reproducibility and to target the application.