Chemistry Reference
In-Depth Information
Planetary Ball Mill
CO
2
R
1
1) Activating Agent
37
/ DMAP
R
1
Waste
water soluble salts
300-450 rpm (Cycled milling
)
OH
OR
3
+
R
2
HN
R
2
HN
OH
10 min x 6 / 50 balls
(
t-
BuOH)
(in the case
of Boc
2
O)
O
O
2) Aqueous acidic work-up
N
O
O
36
R
2
= CO
2
t
Bu, COCH
2
Ph
38
18 examples
35-91%
(in the case
of DSC)
O
R
3
O
Y
2) Aqueous acidic work-up
37
DMAP
N
R
1
DMAP
R
1
R
2
O
OR
3
(cat.)
R
2
N
H
O
H
R
3
=
Me, Et,
CHCH
2
=CH
2
,
CH
2
Ph (ZCl)
O
O
O
R
3
O
Cl
OR
3
OR
3
CO
2
A
B
O
Mixed carboxylic-carbonic
anhydride
O
O
O
R
3
=
R
3
R
3
N
(DSC),
Me (DMC)
=
O
R
3
O
Y
O
37
R
3
O
OR
3
O
R
3
=
t-
Bu (Boc
2
O)
CH
2
Ph (Z
2
O)
Me (Moc
2
O)
Activating agent
O
O
Scheme 6.10 C-Terminal esterification for protection/activation of N-protected amino acids in a planetary ball-mill.
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