CHEM 212
Name __________________
Sample Exam 3
1. (33 pts) Complete the following reactions showing the major organic product or products. Include proper
stereochemistry where necessary.
a.
Robinson
b.
c.
d.
O
O
+
e.
Ph
NaOEt, HOEt
O
H 2NNH 2
KOH, DMSO
f.
O
H2
Pt/C
g.
PCC
OH
h.
CH 2Cl 2
O
O
i.
1) DIBAH
2) H 3O+
O
O
H 2N
1) LiAlH 4
2) H 3O+
O
j.
O
OH
1) SOCl2
2) 2 NH 3
k.
O
1) KOH, H 2O
NH 2
2) H 3O+
Michael
2. (8pts)Completethefollowingsynthesis:
a.
Protect alcohol
OH O
1) LiAlH 4
2) H 3O+
OH
Deprotect alcohol
b.
O
O
Ph
H 2NNH 2
NaOEt, HOEt
DMSO, KOH
Robinson
3. (9 pts) Propose a mechanism for the Fisher Esterification:
O
OH
+
OH
H2SO4 cat.
O
O
+
H2O
4. (9 pts) Propose a mechanism for the base hydrolysis of the following ester (saponification):
O
O
1) KOH, H 2O
O
OH + HO
2) H 3O+
5. (4 pts) Dexon® is a polyester spun into fibers and used for surgical stitches that dissolve over time. Identify the monomer
(repeating unit) that the polymer hydrolyzes into under physiological conditions:
6. (6 pts) trans-Peptidase is the active enzyme that bacteria
use to build their cell walls. Penicillins are potent antibacterial compounds that inhibit this process by binding to
the hydroxyl group of trans-peptidase and rendering it inert.
Shown below are the active end of trans-peptidase and the
structure of penicillin. Propose a process/reaction by which
penicillin binds to the enzyme. Hint: look for the most
reactive carbonyl in the molecule.
CHEM 212 KEY
Name __________________
Sample Exam 3
7. (33 pts) Complete the following reactions showing the major organic product or products. Include proper
stereochemistry where necessary.
a.
by Robinson
b.
c.
d.
O
O
+
e.
O
Ph
by Michael
O
NaOEt, HOEt
Ph
O
H 2NNH 2
KOH, DMSO
f.
O
O
H
H2
+ enantiomer
Pt/C
g.
H
H
PCC
OH
h.
O
CH 2Cl 2
H
O
O
i.
1) DIBAH
O
2) H 3O+
O
O
H 2N
1) LiAlH 4
2) H 3O+
OH
H 2N
O
j.
O
O
OH
1) SOCl2
NH 2
2) 2 NH 3
k.
O
1) KOH, H 2O
NH 2
2) H 3O+
O
OH
8. (8pts)Completethefollowingsynthesis:
a.
Protect alcohol
OH O
OH
TBDMSO
TBDMS-Cl
1) LiAlH 4
2) H 3O+
O
OH
TBDMSO
OH
Deprotect alcohol
OH
OH
Bu 4NF
b.
O
O
O
Ph
H 2NNH 2
NaOEt, HOEt
Ph
DMSO, KOH
Ph
Robinson
9. (9 pts) Propose a mechanism for the Fisher Esterification:
O
+
OH
O
H2SO4 cat.
OH
+
O
H2O
10. (9 pts) Propose a mechanism for the base hydrolysis of the following ester (saponification):
O
O
1) KOH, H 2O
O
OH + HO
2) H 3O+
O
O
O
HO
O
O
O
O H
O
O
HO
H 3O+
O
OH +
HO
+ HO
11. (4 pts) Dexon® is a polyester spun into fibers and used for surgical stitches that dissolve over time. Identify the monomer
(repeating unit) that the polymer hydrolyzes into under physiological conditions:
Monomer is the repeating unit: lactic acid!
O
HO
OH
12. (6 pts) trans-Peptidase is the active enzyme that bacteria
use to build their cell walls. Penicillins are potent antibacterial compounds that inhibit this process by binding to
the hydroxyl group of trans-peptidase and rendering it inert.
Shown below are the active end of trans-peptidase and the
structure of penicillin. Propose a process/reaction by which
penicillin binds to the enzyme. Hint: look for the most
reactive carbonyl in the molecule.
H
N
O
O
H
N
S
N
HO
trans-peptidase
O
O
O
S
O
N
H
O
OH
trans-peptidase
Most reactive
carbonyl
Nucleophilic addition will
relieve strain in 4-membered ring