Transcript Document

Lecture 16
• Get Lecture Problem 6
• The Synthetics
This Week in Lab:
• Ch 9 PreLab Due
• Quiz 5
• Ch 6 Final Report Due
Next Week:
Spring Break!!!
The Condensation Reactions
Experiment 14: Synthesis of 3-Carbethoxycoumarin
O
8
7
6 5
12
3
4
O
Coumarin, the
parent heterocycle:
a flavoring
O
O
O
O
O
OC 2H 5
3-Carbethoxycoumarin:
your synthetic goal
OH
O
Warfarin:
a rat poison
Go over mechanisms for transesterifcation & aldol condensation in class
The Condensation Reactions
Experiment 16: Synthesis of Creatine
H2N C N
+
H
N
O
OH
NaCl
NH4OH
H2O
NH
H2N
O
N
creatine
Go over mechanism in class.
OH
Esterification
O
Synthesis of esters
R
O
R'
A Typical Esterification (generic example):
O
R
O
H +
O
H+
R'OH
R
O
R'
+
H2O
• reaction of a carboxylic acid (elec) with an alcohol (nuc)
• acid catalyzed
• reversible
• known as a Fisher Esterification
Esterification
Experiment 80: Synthesis of Aspirin
O
OH
O
O
OH
+
salicylic acid
O
O
acetic anhydride
H3PO4
OH
+
O
O
acetylsalicylic acid
(aspirin)
• Reaction of an alcohol (nuc) with an anhydride (elec)
• Similar mechanism to Fisher esterification
• Analyses: IR & NMR
Aspirin:
• Anti-inflammatory
• analgesic (pain killer)
• Antipyretic (fever reducer)
O
OH
acetic acid
More Esterifications
Experiment 86: Synthesis of Benzocaine
O
O
OH
OCH 2CH3
H+
+
+ CH3CH2OH
NH 2
1
NH 2
H 2O
2
Benzocaine
• Fisher esterification reaction
• Analyses: IR, NMR & MS
Benzocaine:
• Topical local anesthetic for itching and pain caused by sunburn, insect
bites, poison ivy, poison oak, minor cuts
• Deadens the nerve endings in the skin
Fragrant Esters
O
O
O
O
n-Butyl Acetate
Apple scent
(Experiment 81)
Benzyl acetate
Peach scent
(Experiment 83)
O
O
O
O
Isobutyl Propionate
Fragrance of rum
(Experiment 82)
O
O
Analyses: IR, NMR,
GC, GC-MS, MS
Isoamyl acetate
Banana scent
(Experiment 87)
Methyl Benzoate
Floral fragrance
(Experiment 84)