Today, 9/30:
• “Esterification”
• Grignard reactions
• Next Tuesday, 10/7: Conclusion of Grignard.
• Following Tuesday 10/14:
Practice. Introduction to Unknowns.
Midterm 2:10 – 4pm in your lab
(5 Problems. Total: 100 Pts.) Do Sample Midterms. Review/study
labs with calculations and problems and our lab lectures.
October 22, 6 – 9 pm, Family Science Night
at Oak Grove Middle School!
Methyl Benzoate Synthesis
Esters and Esterifications
1. General properties of esters?
2. Compare the boiling points of carboxylic acids and
esters of similar molecular weight and explain.
3. Examples of esters in biological systems?
Salicin and Aspirin
OH
O
-D-glucose
O OH
C
O
O
Salicin
in willow bark
(Salix)
C
CH 3
Our Esterification Procedure
1. What are the advantages of "boiling under reflux”?
2. What was the purpose of each of the following
extraction steps:
1. rinsing with water
2. then extracting with sodium bicarbonate solution
3. extracting with sat. sodium chloride solution?
3. In our extraction with ether, which was the organic
layer, top or bottom?
4. What would the H-NMR of methyl benzoate look like?
Grignard
Give a definition of "Grignard reagents".
Which products do you obtain from the reaction of a Grignard
reagent with a carbonyl group followed by hydrolysis?
from an aldehyde
from a ketone
from an ester… ?
What type of a reaction is it ….?
RMgX – Ether Complex
• Grignard reagents are metal-organic compounds. Other
examples of metal-organic compounds? Are there any in nature?
CH
CH 2 CH 3
H3 C
CH 2 CH 3
N
N
Mg
H3 C
N
N
CH 3
H
H H
CH 3 OOC
O
O
O
Chlorophyll a
Grignard
Our multistep synthesis of triphenyl methanol, starting
with the synthesis of our Grignard reagent:
Grignard
Adduct
Write the structure of the product obtained if our Grignard
reagent reacts with
a) water
b) methanol
c) benzoic acid
d) carbon dioxide
e) acetone
f) formaldehyde
TLC
Thin Layer Chromatography is an example of
chromatography.
•Do you know other types of chromatography?
•What is common to all types of chromatography?
TLC
What is the moving phase, the stationary phase in
our TLC?
What type of information do we expect from our
TLC?
Next Tuesday:
Conclusion of Grignard.
MiniQuiz!