Chemistry Reference
In-Depth Information
O
S
i
O
Si
O
HO
CO
2
H
Si
O
O
Si
O
H
l
max
365 nm
O
S
i
O
O
+
HO
AcHN
O
O
O
SH
O
Si
DPAP, 1 h
O
HO
Si
O
Si
40
35
(2 eq. x 8 )
OH
OH
HO
HO
AcHN
O
H
HO
O
NHAc
CO
2
H
O
O
O
O
HO
HO
2
C
S
OH
OH
S
HO
HO
CO
2
H
O
H
O
S
i
O
Si
HO
O
O
NHAc
O
S
O
O
S
O
AcHN
Si
O
O
Si
O
Si
O
O
HO
HO
2
C
O
O
S
i
HO
CO
2
H
HO
O
H
OH
OH
S
O
O
HO
O
S
O
O
Si
O
Si
AcHN
O
NHAc
HO
2
C
HO
S
CO
2
H
S
HO
O
O
OH
OH
HO
O
H
O
O
HO
AcHN
HO
2
C
OH
NHAc
HO
41
(35%)
SCHEME 3.12
Synthesis of the POSS-based octavalent sialocluster
41
via TEC.
Synthesis of the PEG-linked octaene silsesquioxane
43
. A solution of octavinyl
POSS
35
(80
mol), 2-[2-(2-hydroxyethoxy)ethoxy]-1-ethanethiol
(336 mg, 2.02 mmol), and DPAP (16 mg, 63.2
mg,
126.4
mol) in DMF (1.4 mL) and THF
(0.7 mL) was irradiated (
max
365) at room temperature for 45 minutes under magnetic
stirring and then concentrated. The residue was eluted from a column of Sephadex
HO
OH
O
O
S
S
O
Si
O
Si
O
Si
O
Si
O
O
HO
S
S
OH
Si
O
O
Si
h
ν
(365 nm), 45 min
O
Si
O
O
Si
O
O
S
i
O
O
OH
2
O
O
S
i
O
2
+
O
HS
O
O
O
O
O
S
i
S
i
DPAP, DMF-THF
O
S
O
O
S
O
Si
O
Si
HO
Si
O
Si
OH
S
S
35
O
42
(99%)
O
HO
OH
O
O
O
O
S
S
O
S
i
O
S
i
O
O
S
S
O
Br
NaH, DMF
0 °C, 3 h
O
Si
O
O
Si
O
O
O
Si
O
2
2
O
O
S
i
S
O
O
S
O
O
Si
O
Si
O
S
S
O
O
43
(98%)
O
O
SCHEME 3.13
PEGylation of octavinyl POSS
35
.
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