Institute of Animal Science, VÚŽV v.v.i., Přátelství 815, Prague 22 Uhříněves, 104 00, Czech Republic.
Institute of Animal Science, VÚŽV v.v.i., Přátelství 815, Prague 22 Uhříněves, 104 00, Czech Republic.
Int J Biol Macromol. 2017 Oct;103:202-207. doi: 10.1016/j.ijbiomac.2017.05.070. Epub 2017 May 17.
Alginic acid is a suitable material for modification to prepare new derivatives because of presence of its carboxyl groups. The high content of carboxyl groups over the entire length of its chain renders it an easily modifiable material with a possibility of achieving a high degree of substitution in the prepared derivatives. The salt of alginic acid (sodium alginate) is readily commercially available and is widely used in many branches of chemistry. Alginic acid was thus selected as the substrate for amidation. The amidation used two-steps: methyl esterification followed by amino-de-alkoxylation. The aim of this study was to prepare highly substituted derivatives with different polysaccharide chain characteristics. As such, the alginic acid was modified by the two-step amidation based on the esterification of the alginic acid carboxyl groups by reaction with methanol and further amino-de-alkoxylation (aminolysis) of the obtained methyl ester with amidation reagents (n-alkylamines, hydrazine and hydroxylamine). The purity and substitution degree of the prepared derivatives were monitored by vibration spectroscopic methods (FTIR and FT Raman) and organic elemental analysis. These analytical methods confirmed the preparation of highly or moderately substituted N-alkylamides, hydrazide and hydroxamic acid of alginic acid.
海藻酸由于其羧基的存在，是一种适合修饰的材料，用于制备新的衍生物。其链上羧基的高含量使其成为一种易于修饰的材料，在制备的衍生物中可以实现高取代度。海藻酸盐（海藻酸钠）的盐很容易在商业上获得，并且广泛应用于化学的许多分支中。因此，海藻酸被选为酰胺化的底物。酰胺化使用两步法：甲酯化，然后脱烷氧基化。本研究的目的是制备具有不同多糖链特性的高取代衍生物。因此，通过两步酰胺化对海藻酸进行修饰，该两步酰胺化基于通过与甲醇反应酯化海藻酸的羧基，然后用酰胺化试剂（正烷基胺、肼和羟胺）对获得的甲酯进行脱烷氧基化（氨基解）。通过振动光谱方法（FTIR 和 FT Raman）和有机元素分析监测制备的衍生物的纯度和取代度。这些分析方法证实了高度或中度取代的 N-烷基酰胺、海藻酸的酰肼和羟肟酸的制备。
