Hybridoma Technology ( Production , Purification , and Application )
Electron pushing
1. Proposed Mechanism:
OH NH2
2-butanol to R-(-)-sec-butylamine
Step 1: Oxidation of Alcohol
OH O
Na2Cr2O7/H2SO4
2-butanol 2-butanone
a. formation of chromate ester
OH O CH3 O
+ HO Cr OH CH3CH2 C O Cr OH + H2O
H
O
O
b. elimination of chromate ester
CH3 O O
CH3CH2 C O Cr OH + H2O
H
O
2. Step 2: Reductive Amination
CH3CH2 C CH3 NH2
O
H2NOH LiAlH4
H2SO4 N
OH
2-butanone 2-butyloxime sec-butylamine
(racemic)
a. protonation of the carbonyl
O OH
H+
CH3CH2 C CH3
b. addition of the amine
OH OH
+ H2NOH CH3CH2 C CH3
CH3CH2 C CH3
NH2OH
c. deprotonation of the amine salt
OH OH
CH3CH2 C CH3 + H2O CH3CH2 C CH2 + H3O
NH2OH NHOH
3. Step 2: Reductive Amination (cont’d)
d. protonation of the alcohol group
OH OH2
CH3CH2 C CH3 + H3O CH3CH2 C CH3
NHOH NHOH
e. loss of water
H H
O
CH3CH2 C CH3
CH3CH2 C CH3
N
NHOH
H OH
f. deprotonation
CH3CH2 C CH3 CH3CH2 C CH3
+ H2O
N N
H OH OH
[work-up]
g. reduction of oxime
NH2
CH3CH2 C CH3 1. LiAlH4/CH3CH2OCH2CH3
2. H2O
N
OH
4. Step 3: Formation of Diastereomers
COO
CH3 CH3
H OH
H NH2 H NH3
HO H
CH2CH3 COOH
CH2CH3
(R)-sec-butylamine H OH
COOH
+
(R)-2-butylammonium
CH3 H CH3CH2OCH2CH3 (R,R) tartrate
HO
NH2 H COO
COOH
CH3
CH2CH3 (R,R)-tartaric acid H OH
NH3 H
(S)-sec-butylamine HO H
CH2CH3
COOH
(S)-2-butylammonium
(R,R) tartrate
[work-up]
Step 4: Recovery of sec-butylamine
COO
CH3 CH3
H OH
H NH3 NaOH H NH2 (R)-sec-butylamine
ethanol (final product)
HO H
CH2CH3 CH2CH3
COOH
COO
CH3 CH3
H OH
H3N H NaOH (S)-sec-butylamine
H2N H (discard)
HO H ethanol
CH2CH3 CH2CH3
COOH