Chitosan Derivatives - Chitosan Based Hydrogels: Functions and Applications - page 55

TAble 2.2
Sulfating Reagents and Reaction Positions of Chitosan or Its Derivatives

Chitosan or its Derivatives Sulfating Reagents Reaction Media Sulfating Positions References

Chitosan Concentrated sulfuric

acid

/ O-6, O-3, and N-2 [119]

Low-molecular-weight
chitosan

Oleum Dimethylformamide O-6 and O-3 [120]

Chitosan Me 3 N-SO 3 Water/Na 2 CO 3 O-6, O-3, and N-2 [121]

OH

Chitosan Cl SO 3 Na Water N-2 [122]

+ Na - O

O

O

Chitosan Water N-2 [123] S

O

O

OTr

O

O SO 3 -pyridine Pyridine O-3 and N-2 [124]

HO

NH 2

OTr

O

SO 3 -pyridine Pyridine O-3 [124]

O

HO

NHAc

OH

O

O

HO

ClSO 3 H or DMF-SO 3 DMF O-6, O-3, and N-2 [125-128]

H

HO

NHR 2

n

R 2 = H, -COCH 3 , octyl,
lauryl. or
-CH 2 CH 2 O(CH 2 CH 2 O)
mCH 3

Chitosan SO 3 -pyridine 5% LiCl/DMAc O-3 and O-6 [129]

O O

S

8:1 (v/v)
acetonitrile/water

Chitosan N-2 [130,131]

O

[113], Drozd et al. [105], and Vongchan et al. [114] have all reported the preparation of
N-sulfated Carboxymethyl chitosan, O -sulfated chitin, 6-O-sulfated chitosan and multi-
substituted sulfated chitosan using HClSO 3 . Hirano et al. [115,116] and Nishimura et al.
[111] and Nishimura and Tokura [117] used a SO 3 -DMF complex to prepare sulfated-chitin
and sulfated-6- O -(carboxymethyl)chitin, while Terbojevich et al. [112] reported the selec-
tive 6-O-sulfation of chitosan with SO 3 -pyridine complex. Holme and Perlin [118] and
Gamzazade et al. [113] used the SO 3 -Me3N complex and the SO 3 -pyridine complex,