Chemistry Reference
In-Depth Information
O
O
O
MeHN
MeHN
MeHN
N
N
N
PhCH
2
N
3
Cu(0), rt
H O/
t
BuOH 1:1
2
K
2
CO
3
cat
N
β
-galactosylazide
32
CuSO
4
Na ascorbate
N
N
N
MeOH
N
Bn
N
Bn
SiMe
3
38
SiMe
3
H
H
2
O/
t
BuOH 1:1
39
40
O
O
NHMe
NHMe
N
OH
N
HO
HO
N
M
(CO)
3
+
H
2
O/MeOH 1:1
65-80 °C, pH 4-5
OH
N
HO
HO
O
N
N
N
O
N
Bn
N
N
N
N
N
OH
N
M
OH
Bn
OC
CO
41
42
CO
M
= Re,
99m
Tc
Synthesis of
99m
Tc complexes based on glucosylated bis-triazolo-amine.
SCHEME 7.8
40
subsequently transformed into the triazole
41
by reaction with the galactosylazide
32
in 86% yield. This sequence can also be performed in one pot in 80% yield. Treat-
ment of
41
with rhenium or technetium carbonyl complexes ([
99m
Tc(CO)
3
(H
2
O)
3
]
+
,
phosphate-buffered saline [PBS] buffer pH 5.5, 80
◦
C-100
◦
C, 20-30 minutes) led to
complexes
42
in good yield (68% with Re).
In an extension of the “click to chelate” approach, thymidine has been labeled
at N-3 position by
99m
Tc using the complexing properties of the triazole linker
(Scheme 7.9) [60]. Thus compound
45
prepared from thymidine
43
via the bromide
O
O
O
Br
N
3
N
N
NH
TBDMSO
HO
HO
N
O
N
O
N
O
1) TBDMSCl,
imidazole, DMF
O
O
O
1) NaN
3
, MeCN
dT
2)
n
Bu
4
NF, THF
2) BrCH
2
CH
2
Br
Cs
2
CO
3
, DMF
HO
HO
HO
45
43
44
O
N
N
R
N
O
N
dT
N
[
99m
Tc(H
2
O)
3
(CO)
3
]
+
PBS, 1h, 100 °C
R
HO
N
O
O
N
H
2
N
N
O
Tc
Cu(OAc)
2
Na ascorbate
H
2
O, 65 °C, 1h
OC
CO
CO
HO
46
47
HOOC
N
S
R =
,
,
,
HOOC
N
NH
2
NH
2
SCHEME 7.9
99m
Tc labeled thymidine.
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