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HO
O
HO
HO
HO
O
N
H
H
N
O
O
H
N
O
HO
O
O
N
3
O
O
H
N
HO
HO OH
HO
HO
HO
49
OH
HO
HO
OH
O
O
O
HO
O
HO
HO
HO
OH
O
H
HO
HO
OH
O
O
O
O
O
NH
O
O
NH
NH
HN
O
O
CuSO
4
NaAsc
THF-H
2
O
12 h
O
O
O
N
NH
N
N
Ru
85%
N
N
H
N
O
N
N
N
N
NH
O
50
Ru
N
N
N
Ru
N
N
N
O
OH
HN
H
N
O
O
OH
HN
51
N
H
O
OH
O
O
O
O
OH
O
O
HO
O
O
O
HO
HO
OH
HN
HN
OH
O
OH
O
O
HN
HN
OH
O
O
OH
O
O
O
HO
O
O
H
O
OH
O
O
OH
HO
HO
OH
OH
O
OH
HO
SCHEME 6.8
Synthesis of Ru(II)-centred click glycodendrimers.
the plant lectin ConA by turbidimetry and quantitative precipitation (Scheme 6.9).
Interestingly, a 75:25 mannose:galactose ratio was found as efficient as the homoge-
nously mannosylated polymer in clusterizing the lectin, implying a 1.5-fold higher
efficiency in a mannose molar basis. Although a saturation effect cannot be dis-
carded, synergic interactions might operate in this case, a phenomenon previously
observed in highly dense heteroglycoclusters and termed heterocluster effect [96,97].
The versatility of the coclicking method allows the incorporation of further different
functionalities in the polymer backbone. For instance, any of the sugar azides can be
coclicked in combination with an azide-armed fluorescent probe to afford fluorescent
glycopolymers that were used to quantitatively assess binding to an immobilized
lectin through affinity HPLC.
The general strategy consisting in the click postfunctionalization of well-defined
alkyne functional polymers with sugar azides has proven extremely powerful to
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