Problem 26 Chemical Structure and Absolute Stereochemistry of Coniine
Problem 26 Chemical Structure and Absolute Stereochemistry of Coniine
Problem 26 Chemical Structure and Absolute Stereochemistry of Coniine
1. CH3I (Excess)
H ∆
H H
H 2. Ag2O, H2O + - CH3CH2CH2
CH3CH2CH2 N CH3CH2CH2 N OH N(CH3)2
CH3 CH3
H A
CH2CH2CH3
1. CH3I H
A H ∆ 1,4 -
2. Ag2O, H2O + Me octadiene
CH3CH2CH2 N +
OH- H
Me Me CHCH2CH3
H
CHCH2CH3
1,5-octadiene
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Problem 27: The chemistry and identification of flavonoids
1.
OCH3
1
8 1'
H3CO 3'' O
6'
5 4'' 4
H3CO O
B
OCOCH3
1
8 1'
H3COCO 3'' O
6'
5 4'' 4
H3COCO O
C
2. a) down field. The 1H-NMR resonance of phenolic proton involvement in hydrogen
bonding will be observed at very low magnetic field (~ 12ppm).
3.
OH
HO OH
OH
HO
D E
4. 13C-NMR would be expected to show three characteristic peaks of the three different
carbonyl groups.
OCOCH3
1
8 1'
H3COCO 3'' O
6'
5 4'' 4
H3COCO O
C
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Problem 28: Synthesis of peptides
1
C6H5
H H
N CO2H N CO2H
H2N H2N
O O
C6H5
Dipeptide II
Dipeptide I
C6H5
H H
N CO2H N CO2H
H2N H2N
O O
C6H5
Dipeptide III Dipeptide IV
The cyclic dipeptides (diketo piperazines) must also be considered:
C6H5
C6H5
O O O
HN HN HN
NH O NH NH
O O
C6H5
DP-I DP-II DP-III
2. Best answers are 5 and 2.
3.
O O
N N
CH3O
CH3O+ MeO
O CH2 O CH2
N N
O O
In the same way the cation from B is better stabilized than the cation from C.
Therefore, the order of increasing lability is: A<C<B<D.
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Problem 29: Oleuropein hydrolysis
1.
COOCH3 COOCH3
O O
R R
O O O
O
O O
O O
OH OH
HO HO
OH OH
OH OH
(a) (b)
2. 3.
OH
OH
HO HO Hd
a b
OH He CH2 CH2 OH
Hc
The correct structure is C
63
Problem 30: Stereochemistry of the Addition Reactions to Alkenes
CH3 CH3
H H
H Br Br H
a) C C
(R) Br H H Br
Br C CH3
H Br H Br
H CH3
CH3 CH3
No Yes
CH3 CH3
H 3C H
H Br H Br
b) C C
(S)
H Br Br H
H C Br
H3C H H Br Br H
CH3 CH3
No Yes
CH3 CH3
H Br H Br H
Br Br CH3
H3C H Br Br H
C (R) C H
(S)
c) C C Br H H Br
H H Br H Br H
CH3 CH3
Yes Yes
CH3 CH3
H Br
H Br H Br
H3C C (R) H
H Br Br H
d) C C
(S)
H C Br H Br Br H
H3C H H Br H Br
CH3 CH3
No No
64
Problem 31: Identification of Organic Compounds
CH3
C
C CH2CH2CH3
H
H2/Pd/C
CH3 CH3
(A)
H2/Lindlar
CH3
CH
CH COOH COOH
H H COOH H COOH
O3 I2/NaOH
CH3 OH
KMnO4 -CHI3
CH3 O O
(B) (C)
Problem 32: Lipases
a)
O O O O O O
HN H
O O O
c)
65