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In-Depth Information
O
O
O
Br
N-(ethyl)-2-
pyridylmethanimine
Br
O
n
O
O
+
O
O
Si
CuBr, toluene,
70 ˚C
52
53
54
Si
O
TBAF, AcOH,
THF
Br
O
x
y
O
O
O
O
O
Br
OH
O
OH
Cu(I)
n
N
HO
HO
O
N
N
N
O
O
N
N
55
O
OH
OH
HO
HO
O
HO
HO
O
O
HO
OH
56
O
N
3
58
OH
DP(x + y) = 90
HO
O
O
N
3
HO
OH
57
SCHEME 6.9
Synthesis of heteroglycopolymers through co-clicking strategies.
produce neoglycopolymers capable to interfere in carbohydrate-protein recogni-
tion events [98-104]. Mono-, di-, and trisaccharides with terminal D-mannose, D-
galactose, and D-glucose motifs have been appended either directly through the
anomeric position or through a spacer arm. It is worth highlighting that the presence
of an anomeric triazole ring does not seem to compromise lectin recognition [98].
The possibility to coclick different functional elements onto the polymer backbone
can be complemented with the incorporation of an orthogonal reactive functional-
ity at the chain end for bioconjugation purposes. In a notable example, Haddleton
and coworkers exploited the capability of novel maleimide-terminated glycopoly-
mers to selectively react then with the free-cysteine residue of bovine serum albumin
(BSA) to prepare neoglycopolymer-protein hybrid materials (Scheme 6.10) [105].
Copolymerization of
52
and the fluorescent rhodamine B derivative
59
in the pres-
ence of the maleimide-protected initiator
60
afforded the poly(propargyl methacry-
late)
61,
which was later on coclicked with 2-azidoethyl
-D-mannopyranoside and
-D-galactopyranoside at different ratios. The resulting fluorescently labeled het-
eroglycopolymers were activated by a retro-Diels-Alder reaction to generate the
maleimide moiety that was then conjugated to BSA (
62
). Surface plasmon reso-
nance (SPR)-binding studies showed clear and dose-dependent binding of the result-
ing neoglycopolymer-BSA conjugates to recombinant rat mannose-binding lectin
(MBL), a key mammalian lectin of the immune system. Moreover, these biomaterials
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