Chemistry Reference
In-Depth Information
OAc OAc
OAc
immobilized lipase
CNBr-ANL
AcO
O
O
AcO
OAc
OH
buffer:CH
3
CN = 80:20
pH 5, 25
o
C
AcO
OAc
OAc
95%
OAc
OAc
AcO
OH
immobilized lipase
octyl-TLL
O
O
OAc
AcO
buffer:CH
3
CN = 80:20
pH 5, 25
o
C
AcO
OAc
OAc
OAc
95%
immobilized lipase
CNBr-TLL
OAc
OH
O
AcO
AcO
O
buffer:CH
3
CN = 80:20
pH 5, 25
o
C
AcO
OAc
AcO
OAc
OAc
OAc
63%
OAc
OH
immobilized lipase
CNBr-ANL
O
AcO
O
AcO
AcO
OAc
AcO
OAc
buffer:CH
3
CN = 80:20
pH 5, 25
o
C
NHAc
NHAc
65%
FIGURE 1.14
Specific and regioselective hydrolysis of different 1,2,3,4,6-penta-
O
-acetyl-
D-glycopyranoses using immobilized lipases [29].
chemoselectivity to provide the methyl ester equipped with three OH groups and PLE
hydrolyses the methyl ester groups with high chemoselectivity to provide glucuronic
acid containing three acetyl groups. Any combination of two esters leads to high
yields (90% or more) of glucuronic acids with unchanged substituent at the aglycone
position (Fig. 1.15).
CO
2
H
CO
2
H
Cl
CH
3
CO
2
H
N
CH
3
N
H
3
C
H
MeO
Cl
(S)
-naproxen (NP)
mefenamic acid (MF)
diclofenac (DF)
MeO
2
C
HO
2
C
MeO
2
C
R
R
O
Cs
2
CO
3
DMSO
O
LAS
PLE
O
O
AcO
AcO
O
+RCO
2
H
Ac
AcO
H
HO
O
O
OAc
Br
AcO
HO
FIGURE 1.15
Chemo-enzymatic synthesis of 1-
-
O
-acyl glucuronides described by Baba
and Yoshioka [31].
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