Abstract
Coumarins are a class of natural products with a wide range of biological activities. Few synthetic routes for these compounds are able to make exclusively 7-substituted coumarins. Existing methods generally require harsh reaction conditions and/or require expensive catalysts. This project adapted a one-pot Pechmann reaction employing meta-phenols and 3,3-dimethoxypropionate—a β-aldehyde ester rather than the typical β-keto ester—to examine its efficacy for synthesizing exclusively 7-substitued coumarins. Despite testing four acid catalysts, only trifluoroacetic acid yielded the desired product, albeit with a low yield of 3%. Additionally, an alternative two-step acylation and cyclization sequence using three base catalysts—NaHMDS, NaOMe, and NaOtBu—was performed. This approach was successful only with NaHMDS and NaOMe, giving yields of 5.7 % and 1.5 % respectively. The NaOtBu-facilitated reaction led to unknown byproducts which will be further analyzed with advanced instruments. Future work will focus on elucidating the reaction products with NaOtBu, developing conditions leading to increased yields when using NaHMDS and NaOMe, and assessing the impact of varying phenolic R groups on the selectivity for 7-substitued coumarins compared to 5-substituted coumarins.
Advisor
Martin, Sara
Department
Chemistry
Recommended Citation
Yeo, Aileen, "Toward a More Efficient and Selective Synthesis of Exclusively 7-Substituted Coumarins" (2024). Senior Independent Study Theses. Paper 11188.
https://openworks.wooster.edu/independentstudy/11188
Disciplines
Organic Chemistry
Keywords
Coumarins, Pechmann reaction, Acylation-Cyclization, Organic synthesis
Publication Date
2024
Degree Granted
Bachelor of Arts
Document Type
Senior Independent Study Thesis
© Copyright 2024 Aileen Yeo
