Chemistry Reference
In-Depth Information
Scheme 8.1
Grafting procedures with epoxide- or anhydride-terminated polymers (R
¼
polymeric
chain) [
22
]
Scheme 8.2
Grafting procedure on the
N
-acetylglucosamine primary hydroxyl groups performed
in aprotic polar solvents employing HA-TBA; in particular a direct coupling strategy on activated
polymers is described. (
a
) Reaction with
N
-hydroxysuccinimide or imidazole-activated carboxyl-
terminated polymers [
23
]. (
b
) Reaction with acyl-chloride-activated carboxyl-terminated
derivatives [
24
]. (
c
) Reaction with cyclic or linear anhydride-functionalized polymers [
50
]
(R
¼
polymeric chain)
N
-hydroxysuccinimides or carbonyldiimidazoles (Scheme
8.2
a) [
23
]. Such kind of
activators has the advantage to be suitable for a wide range of polymers both
synthetic and natural including short polypeptides. Carboxyl-terminated polymers
could be also activated as acyl-chloride derivatives, thus allowing faster reactions
[
24
]. However, some concerns can be issued considering the reactivity and toxicity
of thionyl chloride employed to perform the activation and about the release of HCl
during the coupling reaction (Scheme
8.2
b). Ester linkages can be also obtained
performing the
reaction with polymers having anhydride
functionalities
(Scheme
8.2
c) [
25
].
