Biomedical Engineering Reference
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O
OH
OH
B
O
A
O
O
O
O
HO
O
O
HO
HO
O
N
N
NH
2
O
O
n
n
n
C
Tr
Tr
OH
O
O
O
E
D
O
O
O
O
HO
O
HO
HO
NH
NH
NH
2
O
O
n
n
n
+
Cl
-
+
Cl
-
N
N
H
3
C
CH
3
H
3
C
CH
3
CH
3
H
3
C
Tr =
Figure 2.8
Synthetic route for the preparation of chitosan
N
-betainates: (A) phthalic anhydride, DMF/water, 120°C, (B)
triphenylchloromethane, pyridine, 90°C, (C) hydrazine monohydrate, water, 120°C, (D)
N
-chlorobetainyl chlo-
ride (1, 2, and 4 equivalents), pyridine, room temperature, and (E) aq. HCl, room temperature.
(a)
Tr
Tr
O
O
OH
NR
3
Aq. HCl
O
O
O
O
HO
O
O
HO
HO
NH
NH
NH
O
O
n
O
n
n
Cl
R
3
N
R
3
+
+
N
N
NR
3
:
N
N
N
(b)
Tr
Tr
N
O
OH
O
Aq. HCl
O
O
O
O
O
HO
O
HO
HO
NH
NH
NH
O
O
O
n
n
n
Cl
+
+
Figure 2.9
Synthetic route for the preparation of various quaternary ammonium chitosan derivatives via
N
-chloroacyl-6-
triphenylchitosans (a and b).
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