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HO
HO
OH
N
N
O
HO
OH
HO
OH
OH
O
OH
N
N
HO
HO
O
N
N
N
N
OH
N
N
N
OH
OH
N
O
HO
HO
O
N
N
N
HO
N
N
OH
OH
19
OH
O
OH
AcO
20
OEt
O
AcO
AcO
HO
O
OH
N
N
N
EtO
N
N
N
N
OAc
N
O
AcO
N
OAc
AcO
OAc
OAc
21
O
EtO
FIGURE 6.1
Examples of click glycoconjugates with
C
-linked and non-anomeric
N
-linked
glycoligands.
Santoyo-Gonzalez
and
coworkers
with
the
preparation
of
click
per-(C-
6)-cyclomaltohepatose
-D-
mannopyranosides [26]. In a latter report, the same group extended the application
of the
(
-cyclodextrin,
CD)-scaffolded
hepta-
O
-
and
S
-
CD platform to the preparation of analogs hepta-
O
-
-D-galactopyranosides
and hepta-
O
-
-lactosides (
24
), as well as to fluorescently labeled galactopyranoside
conjugates (
25
) obtained by coclicking the
CD heptaazide
22
with propargyl
-D-
galactopyranoside and the propargyl dansyl derivative
23
(Scheme 6.4) [52].
The efficiency of the triazole-forming reaction was further demonstrated with
the preparation or per-(
O
-2,
O
-3)-substituted,
CD-centered tetradecavalent galac-
tosyl and lactosyl clusters. These compounds had the capability to promote cell
adhesion and stimulation of monocytes, thereby mimicking the lipopolysaccharide
(LPS) effects [52]. Other authors have exploited the capabilities of cyclomaltohexaose
(
CD) to form polyrotaxanes to increment the functionality of mono-,
di-, or triazido-substituted units by threading them on polyethylene glycol chains that
are blocked at the ends with bulky stoppers before clicking the desired glycotopes
[53]. Alternatively, monovalent click conjugates can be used to form pseudorotax-
anes that are click-assembled in a later step to create multivalent polyrotaxanes [54].
Although intellectually very appealing, these strategies suffer from the intrinsically
low yields of cyclodextrin rotaxanation.
Polyaromatic containers of the calixarene type and their relative resorcinarenes
(resorcarenes) have been largely used for the construction and application of novel
-cyclodextrin,
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