Chemistry Reference
In-Depth Information
N
N
N
O
O
N
N
N
N
O
O
N
N
O
O
HO
O
O
HO
HO
O
O
HO
NHAc
HO
O
HO
4
NHAc
HO
NHAc
10
FIGURE 12.6
Triazolyl glycocluster having antitumor property.
(
11
), (
12
) bearing azido groups either at anomeric position or at
C
-6 and an alkyne
functionality in the form of either a 6-
O
-or1-
O
-propargyl on cyclo-oligomerization
via click reaction using CuSO
4
/Cu turnings in DMF afforded corresponding macro-
cycles. These macrocycles served as a template for enzymatic sialylation with TcTS
in presence of MUNANA as sialic acid donor delivering (
13
), (
14
), (
15
), and (
16
),
respectively (Scheme 12.3) [44].
Galectins are a family of cytosolic
-D-galactoside binding proteins, which
strongly modulate their expression during development, differentiation stages, and
under different physiological or pathological conditions. Studies demonstrated that
Gal-3 is involved in colon cancer metastasis, brain tumor progression, inhibition of
metastasis-associated cancer cell adhesion, and may play a key role in innate immu-
nity. Other reports suggest that Gal-3 and Gal-1 can regulate apoptosis processes,
and Gal-1 acts as an insoluble host factor that promotes HIV-1 infectivity through
stabilization of virus attachment to host cells [45].
Carbohydrate ligands of natural occurrence exhibit weak affinity for galectins,
therefore galactosides and lactosides-based monovalent and multivalent triazole clus-
ters were prepared by Giguere et al. with the anticipation of better binding capacity
and selective inhibition of Gal-1 over the other galectins. Evaluation of monovalent
compounds showed maximum inhibitory activity for triazolyl galactoside (
17
) with
inhibitory properties of 1250
M for both inhibitors whereas trivalent lactoside (
18
)
registered inhibitory properties of 20
M for galectins [45].
Tejler et al. prepared the acetylene derivatives of various natural and nonnatural
amino acids and clustered them with complex 2-azidoethyl
-D-galactopyranosyl-
(1
→
4)-
-D-glucopyranoside
via
regioselective
copper(I)-mediated
1,3-dipolar
Search WWH ::
Custom Search