Preparation of dextran-bioactive compound adducts by the direct esterification of dextran with bioactive carboxylic acids

✍ Scribed by Manuel Sánchez-Chaves; Felix Arranz

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 448 KB
• Volume: 38
• Category: Article
• ISSN: 0032-3861
• DOI: 10.1016/s0032-3861(96)00806-3

✦ Synopsis

The direct esterification reaction of dextran with c~-naphthylacetic acid (a model bioactive carboxylic acid) is studied in homogeneous phase using pyridine-sulfonyl chloride as catalyst. The structure of the resulting adducts was determined by means of infra-red, 1H nuclear magnetic resonance (n.m.r.) and 13C n.m.r. spectroscopy. The influence of the pyridine concentration, the type of the sulfonyl chloride as well as the temperature was evaluated. Direct esterification reaction was also performed with other bioactive carboxylic acids, such as naproxen and nicotinic acid. 13C n.m.r, spectra at 75.4 MHz of partially modified dextran with c~-naphthylacetate groups were studied in order to evaluate the selectivity of the reaction between dextran and c~-naphthylacetic acid. Analysis of the spectra of ring carbons in the anhydroglucose units shows that the reactivity of the individual hydroxyl groups decreases in the order C2 > C4 > C3. On the basis of these results a probable mechanism for the reaction is suggested.