Transcript AMINO ACIDS Ethan Secor, John N. Gitua (Mentor)

METALLORGANIC SYNTHESIS OF -AMINO ACIDS
Ethan Secor, John N. Gitua (Mentor)
Department of Chemistry, College of Arts and Sciences
Drake University
RESULTS
Amino acids are important biological compounds and are widely used in
chemical synthesis. They are characterized by a carboxylic acid group
and an amine group. When these groups are attached to the same
carbon atom the compound is known as an -amino acid.
Here we present a mechanism for synthesis based on the metallorganic
reaction of imines.
SUMMARY
PROPOSED REACTION MECHANISM
Infrared spectra suggest the presence of a carboxylic acid functional group
The reaction and products are sensitive to conditions such as exposure to air and
heat.
% Transmittance
INTRODUCTION
The proposed reaction for a-amino acid synthesis uses a metallorganic
mechanism. A titanium complex coordinates to the C=N double bond,
and carbon dioxide inserts into this metallocycle. Upon hydrolysis, the
ring is cleaved and the product is formed. The product was isolated
using a series of extractions and characterized by infrared spectroscopy.
1) Ti complex, BuLI
-78⁰C, THF
2) Carbon Dioxide
RT
3) Hydrochloric Acid
RT
Wavenumber (cm-1)
CONCLUSIONS
The infrared spectra suggest there may be amino acid formation
The results are not conclusive
•
UV-Vis should be done and compared to a standard
•
NMR data would help ascertain identity
•
RPLC would help ascertain purity
EXPERIMENTAL PROCEDURE
The titanium complex was prepared in purified tetrahydrofuran using
titanium(IV) isopropoxide and butyl lithium at low temperatures
maintained by mixing acetone and dry ice. The imine was added to this
mixture. The reaction mixture was gradually warmed to room
temperature. Carbon dioxide was introduced from the sublimation of dry
ice. Finally, hydrochloric acid was added to quench the reaction. The
organic layer was extracted, and the aqueous layer was neutralized with
sodium hydroxide. Diethyl ether was added to the aqueous layer and
extracted. The two organic extractions were dried and characterized by
infrared spectroscopy.
FUTURE WORK
Further work will be performed using different imines for the preparation of -amino
acids and other classes of amino acids. Other analytical techniques, such as NMR,
will by used to characterize reaction products.
REFERENCES
Spectral Database for Organic Compounds, SDBS. AIST.
SDBSWeb : http://riodb01.ibase.aist.go.jp/sdbs/ (National Institute of
Advanced Industrial Science and Technology)