Amino Derivatives of Starch Part 1: Amination of Amylose Oxidized with Nitrogen Dioxide

Abstract

Amylose oxidized with nitrogen dioxide, having D.O. by (C=O) 0.38 and by (COOH) 0.94 was converted into its oxime, which after reduction with sodium and isopropyl alcohol yielded (1→4)‐2‐amino‐2‐deoxy‐α‐glucopyranuronan with D.S. by (NH2) 0.30 and by (COONa) 0.85. After acetylation and O‐deacetylation (1→4)‐2‐acetamido‐2‐deoxy‐α‐d‐glucopyranuronan with D.S. by (NHCOCH3) 0.28 and by (COONa) 0.80 was obtained.

Preparation of water‐soluble oxidized starch with high carbonyl content by sodium hypochlorite

“…The hydroxyl groups of starch molecules are oxidized first into carbonyl groups and then into carboxyl groups. The introduction of carbonyl groups into starch affords reactive groups that can be subjected to further modification, such as amination , alkylation through reductive amination , and grafting of functional molecules containing amino or hydroxyl groups. The introduction of carboxyl groups improves the hydrophilicity of starch and provides starch with new functionality.…”

“…With permanganate, starch can be oxidized with a fairly low oxidation degree . The application of N 2 O 4 or the combination of N 2 O 4 with periodate is effective for the preparation of high‐carboxyl‐content oxidized starch except for the toxicity of N 2 O 4 . In the industry‐manufacture, sodium hypochlorite is the most commonly used oxidant for a low degree of starch oxidation .…”