1 (497)

Prévia do material em texto

Solutions for Carboxylic Acids
EtO
HC OH
EtO
HC OH
O
H H
HC OH
O Et
H
O
H
H
O
H
HC
O
OH
H
HC
O
OH
H
O
H
EtO
HC OH
HC
O
OH
H
HC
OH
OH
O Et
HC OEt
O
EtO
HC OH
OH
H
(b)
17 continued
H
H C
O
OH
C
O
OH ∆
+ H2O
18
(a) H3C HN(CH2CH3)2
C
O
O
H3C
H2N(CH2CH3)2
C
O
NEt2
H3C
NH2 ∆
+ H2O
(b) NH3HO C
O
CH3
O C
O
CH3
H
N
C
CH3
O
(c) (CH3)2NH
HO C
O
H
(CH3)2NH2 O C
O
H
∆
O
HN
H3C
CH3
+ H2O
19 B H and BH • THF can be considered as equivalent reagents.2 6 3
CH2 C
O
Cl
C OH
O
CH2 LiAlH4
B2H6
1) LiAlH(O-t-Bu)3
H3O+
H3O+
COOHO B2H6 H3O+ CH2OHO
C H
O
CH2
CH2 CH2OH(a)
(b)
or
B2H6 (or BH3 • THF) selectively 
reduces a carboxylic acid in the 
presence of a ketone. Alternatively, 
protecting the ketone as an acetal, 
reducing the COOH, and removing the 
protecting group would also be 
possible but longer.
(c)
− EtOH
2) H3O+
H A
H A
492