Preparation and Anticoagulant Activity of Sulfated 6-Carboxychitosan

6-Carboxychitosan (6-CC), prepared by selectively oxidization of chitosan powder with NO
₂
gas in glacial acetic acid, was sulfated with chlorosulfoni acid in formamide to give sulfated 6-carboxylchitosan (S6CC). In S6CC, -SO
₃
H groups were primarily grafted on -NH
₂
, next on secondary -OH, and thirdly on -CH
₂
OH positions. Sodium salt of S6CC (Na-S6CC) was more similar with heparin sodium than sulfated chitosan in both structure and anticoagulation activity.