This document summarizes Carmelle Yeager's undergraduate research project to synthesize S-alkyl analogues of methionine under the supervision of Dr. James Dowden. The document outlines the goals, methods, and results of the project. The goals were to chemically synthesize S-alkyl analogues of methionine using S-benzyl homocysteine and birch reduction. Several key reaction steps and purification techniques are described for synthesizing intermediates. While one intermediate was successfully synthesized, the attempt to synthesize S-(prop-2-yn-1-yl) homocysteine using the birch reaction was unsuccessful and will require further purification techniques. Moving forward, the document proposes coupling the

1. Synthesizing S-alkyl
analogues of methionine
Carmelle Yeager
University of Nottingham Department of Chemistry
Under the Supervision of Dr. James Dowden
August 13, 2015

2. Overview
I. Introduction
II. Methods and Techniques
III. Results
IV. Moving Forward

3. SAAM Mechanism: Modified from Figure 1: Schematic description of profiling genome-wide chromatin
methylation with a native or engineered posttranslational apparatus within a living cell,
Wang, Rui.

4. SAAM Mechanism: Modified from Figure 1: Schematic description of profiling genome-wide
chromatin methylation with a native or engineered posttranslational apparatus within a living cell,
Wang, Rui.

5. Cytoplasm
SAAM Mechanism: Modified from Figure 1: Schematic description of
profiling genome-wide chromatin methylation with a native or engineered
posttranslational apparatus within a living cell,
Wang, Rui.

6. The Big Question
Which PMTs methylate which proteins or
genes?

7. Tags
SAAM Mechanism: Modified from Figure 1: Schematic description of profiling
genome-wide chromatin methylation with a native or engineered
posttranslational apparatus within a living cell,
Wang, Rui.

8. In Vitro…
SAAM Mechanism: Modified from Figure 1: Schematic description of profiling
genome-wide chromatin methylation with a native or engineered
posttranslational apparatus within a living cell,
Wang, Rui.

9. Project Goal
 Chemically synthesize S-alkyl analogs of
methionine
◦ Use S-benzyl homocysteine and birch reduction

10. Methods: The Tag (Compound A)
 Synthesis of (Z)-1-Bromo-4(prop-2-yn-1-
yloxy)but-2-ene
◦ Step-wise procedure
◦ Silica column purification
◦ Mass Spectral Analysis (TOF)
◦ HNMR

11. Methods: The Methionine Base
 Synthesis of S-Benzyl homocysteine
◦ Stepwise synthesis
◦ Silica column purification
◦ Mass Spectral Analysis (TOF)
◦ HNMR analysis

12. The overall reaction

14. Synthesis of (E)-2-amino-5-((4-prop-2-
yn-1-yloxy)but-2-en-1-yl)thio)pentanoic
acid (Compound B)
 Birch Reduction: Reduced in liquid
ammonia and sodium pieces and refluxed
in EtOH coupled with alkylation step

15. Birch Reduction Mechanism

16. Step two: Add the Alkyl Group

17. The Mayhem of Birch Reductions!
Nitrogen gas line
Liquid ammonia
Reaction Flask

19. Failed attempt at S-(prop-2-yn-1-
yl) homocysteine

20. What’s Next?
SAAM Mechanism: Modified from Figure 1: Schematic description of
profiling genome-wide chromatin methylation with a native or engineered
posttranslational apparatus within a living cell,
Wang, Rui.

21. Click Chemistry!
Click Chemistry Mechanism for Elution of DNA; modified from Figure 4:
Profiling genome-wide chromatin modification of G9a and GLP1, Wang, Rui.
Triazine Ring

22. Click Chemistry Mechanism
Click Chemistry Mechanism: Taken from Dr. Scaglione’s Powerpoint

23. Conclusions
 Able to synthesize Compound B
 Unable to synthesize S-(prop-2-yn-1-yl)
homocysteine using Birch Reaction
◦ further purification techniques needed
 Couple the SAAMs to adenosine with
engineered MATs for in vitro testing

24. Acknowledgements
Thronson Scholarship
Dr. James Dowden
Dr. Tim Birkenshaw
Kevin Grant
Tom Tongue
Rasha Abdullaha

25. References
 Nelson, David L., Cox, Michael M. Lehninger Principles of Biochemistry Sixth
Edition; W.H. Freeman and Company: New York, 2013; pp 709-713.
 Wang, Rui, Islam, Kabirul, & Luo, M. (2013). Profiling Genome-Wide Chromatin
Methylation with Engineered Posttranslational Apparatus within Living
Cells. Journal of the American Chemical Society, 135(3): 1048-1056.
doi: 10.1021/ja30412s.
 Wang, R., Zheng, W., & Luo, M. (2014). A sensitive mass spectrum assay to
characterize engineered methionine adenosyltransferases with S-alkyl
methionine analogues as substrates. Analytical Biochemistry, 45011-19.
doi:10.1016/j.ab.2013.12.026
 Zhang, R., Li, X., Liang, Z., Zhu, K., Lu, J., Kong, X., & Luo, C. (2013).
Theoretical Insights into Catalytic Mechanism of Protein Arginine
Methyltransferase 1. PlosONE,8(8),1.
doi:10.1371/journal.pone.0072424