1. Aaron Chung, Sarah Joiner
The Synthesis of trans-9-(2-phenylethenyl)anthracene
Aaron Chung, Sarah Joiner
Department of Chemistry, University of New Hampshire, Durham, NH
12/9/16
Introduction
Results and Discussion
Future Work
Chemiluminescence is one of the major tools in modern chemistry, biology, and medicine as it permits quantitative determination of various compounds at low concentrations1. By Wittig reaction, trans-9-(2-phenylethenyl)anthracene can be synthesized, which can used in a wide variety of chemiluminescent experiments due to its blue fluorescence2. Proper preparation of the ylide and aldehyde will ideally yield an efficient synthesis while also exploring procedural improvements.
Synthesis towards the desired product could be achieved more efficiently by oxidizing the starting material in an alternative manner. A Pyridinium Chlorochromate oxidation could produce the intermediate product, 9-anthraldehyde, in better yields and purity4. Synthesis could be attempted once more with TLC to monitor the reaction/purity. If the product was properly synthesized, future chemiluminescent experiments could have been performed. B D C E F
Experimental
A multistep synthesis was performed, starting with 9-anthracenemethanol to yield trans-9-(2-phenylethenyl)anthracene. The starting material was oxidized by performing a classic Swern oxidation to yield the intermediate product, 9-anthraldehyde3. A
Conclusion
Figure 1. 1H NMR of Crude 9-anthraldehyde
Synthesis of the starting materials was completed, however, the target product requires further studies. Trans-9-(2-phenylethenyl)anthracene was not successfully synthesized, suggesting alternative routes be utilized.
Scheme 1. Oxidation of 9-anthracenemethanol
Acknowledgements
A phosphonium ylide was prepared by an overnight reflux with triphenylphosphine and benzyl chloride in toluene, yielding benzyltriphenylphosphonium chloride. The aldehyde was treated with the ylide in a Wittig reaction to yield the desired product, trans-9-(2-phenylethenyl)anthracene.
I would like to thank the UNH Department of Chemistry, David Danico, Graham Beaton, William Butler and Sarah Joiner.
References
Figure 2. 1H NMR of Contaminated Product
1. W.R.G. Baeyens, S.G. Schulman, Y. Zhao; Chemiluminescence-Based Detection: Principles and Analytical Applications in Flowing Streams and in Immunoassays. Journal of Pharmaceutical and Biomedical Analysis. 1998, 17(6-7), ( )
2. Jaworek. Christine, Lacobucci. Sarah; Wittig Reaction: The Synthesis of trans-9-(2-phenylethenyl)anthracene Revisited. Journal of Chemical Education. 2002,79,(111)
3. Yusuke.O; Hikaru.S; Shigefumi.K; Total Synthesis of Amphirionin-4. Organic Letters. 2016, 18, ( )
4. Luzzio A. Fredrick; Fitch W. Richard; Moore J. William; Mudd J. Kelli; A Facile Oxidation of Alcohols Using Pryidinium Chlorochromate/Silica Gel. Journal of Chemistry Education. 1999, 76(9), ( )
The 1H NMR of 9-anthraldehyde, Figure.1, exhibits a small aldehyde peak at 11.8ppm, which suggests that the Swern oxidation resulted in crude product. Due to time constraints, the crude product was not purified any further.
The Wittig reaction resulted in contaminated product, as starting material is still illustrated within the spectrum. Furthermore, the melting point of the final product, ( )°C, did not match literature values.
Scheme 2. Wittig Reaction of 9-anthraldehyde
Each product was analyzed by 1H NMR and
melting point, when applicable, to determine purity.