O-maleoyl derivative of low-molecular-weight κ-carrageenan:: Synthesis and characterization

Low-molecular-weight (LMW) kappa-carrageenan was achieved through mild hydrochloric acid hydrolysis of kappa-carrageenan. The acylation of low-molecular-weight kappa-carrageenan was performed by use of tetrabutylammonium (TBA) salt of the anionic polysaccharide fragments, maleic anhydride, 4-dimethylaminopyridine and tributylamine under homogeneous conditions in N,N-dimethylformamide at 60 degrees C. Analysis of FT-IR spectrum of O-maleoyl kappa-carrageenan showed that a monoester derivative with maleoyl group was formed when LMW kappa-Carrageenan reacted with maleic anhydride. Investigation of H-1 NMR spectroscopy revealed that the maleoylation took place regioselectively at C-2 of the kappa-carrageenan 3-linked unit. (C) 2005 Elsevier Ltd. All rights reserved.