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

Esterification of Polysaccharides

“…13 C NMR spectra of partially modified dextran with α-naphthylacetate moieties show that the reactivity of the individual hydroxyl groups decreases in the order C-2 > C-4 > C-3. This distribution is comparable with the one obtained for the acetylation of dextran with acetyl chloride/Py [202]. On the basis of these results, a mechanism for the reaction is suggested, which includes formation of an acylium salt, as observed for the reaction with acid chlorides (Fig.…”

“…The reaction is influenced by the temperature, Py concentration, and sulphonic acid chloride (Table 5.18, [202]). The esterification is possible even without the base.…”

Structure Design of Multifunctional Furoate and Pyroglutamate Esters of Dextran by Polymer‐Analogous Reactions

“…[11,12] For the functionalization with complex and sensitive acids, the homogeneous reaction of carboxylic acids after in situ activation is an important path. The most popular in situ activating agents are sulfonic acid chlorides, [13] N,N 0 -dicyclohexylcarbodiimide (DCC), [14,15] and N, N 0 -carbonyldiimidazole (CDI). [16] A new approach of multiple functionalization through in situ activation with CDI, which leads to derivatives with a defined structure and adjusted properties, is discussed in this paper.…”

“…NMR spectra were acquired on a Bruker AMX 250 and DRX 400 spectrometer with 16 scans for 1 H NMR (room temperature) and 200 000 scans for 13 C NMR (70 8C) measurements (25 mg sample Á mL À1 for 1 H NMR and 100 mg sample Á mL À1 for 13 C NMR studies). FT-IR spectra were recorded on a Nicolet AVATAR 370 DTGS spectrometer with the KBr-technique.…”

“…13 C NMR spectrum of dextran sample 2 (produced by Leuconostoc mesenteroides, M w ¼ 54 400 g Á mol À1 ) in DMSO-d 6 (index s indicates the non-reducing end group).…”