Chemistry Reference
In-Depth Information
OH
OH
HO
OH
OH
HO
O
S
O
S
HO
HO
O
183
O
184
OH
N
O
N
HO
HO
N
N
N
N
O
OH
HO
HO
HO
OMe
OH
OH
OH
OH
OH
OH
OH
OH
O
HO
HO
OH
OH
O
OH
S
O
O
S
O
OH
HO
S
HO
S
N
O
O
n
N
N
O
N
N
N
OH
N
N
O
N
185
186
OH
O
O
N
HO
HO
HO
O
HO
N
N
HO
HO
OH
OH
OH
OH
OH
OH
OH
OH
OH
HO
OH
OH
HO
O
OH
O
OH
OH
HO
OH
O
HO
S
O
S
HO
OH
S
O
OH
S
OH
OH
O
S
OH
O
HO
OH
n
n
O
O
O
OH
HO
O
N
n
n
S
N
O
N
N
N
S
N
N
N
n
O
O
N
N
N
N
O
HO
HO
HO
HO
HO
O
N
n
HO
O
O
HO
N
O
O
OH
N
HO
N
N
HO
n
N
O
O
OH
HO
N
N
188
187
N
SCHEME 5.43
Multivalent S-galactosides on carbohydrate scaffolds.
the interglycosidic oxygen atom by a sulfur atom in glycoclusters could increase the
resistance to hydrolytic degradation by enzymes and can even cause inhibition of this
activity. Recently, we reported the synthesis of a family of glycoclusters based on
carbohydrate scaffolds bearing one to four S-galactoside epitopes and EG spacers of
different lengths (Scheme 5.43). The click reaction between thiogalactoside residues
and azide oligosaccharide scaffolds was performed under microwave irradiation,
in moderate to excellent yields, depending on the valencies of the desired products
(72-100% for monovalents, 60-84% for divalents, 54-67% for trivalents and 50%
for tetravalents) [67].
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