Base-Catalyzed Synthesis of Flavones via Thiol-Assisted Sequential Demethylation/Cyclization of 1-(2-methoxyphenyl)prop-2-yn-1-ones

Submitting author affiliation:
Universidade Federal da Fronteira Sul, Cerro Largo, Brazil

Beilstein Arch. 2021, 202158.

Published 16 Aug 2021

This preprint has not been peer-reviewed. When a peer-reviewed version is available, this information will be updated.


Flavone and analogues represent an important class of biologically and pharmacologically active substances commonly found in the composition of diverse plants as part of the class of secondary metabolites. Herein, we have demonstrated an efficient and regioselective synthetic strategy for the preparation of functionalized flavones through sequential demethylation/6-endo-dig intramolecular cyclization of propyn-1-ones, using catalytic amounts of base in the presence of a thiol, by employing NMP as the solvent. The reactions proceeded smoothly under transition-metal-free and open to air conditions, furnishing the desired six-membered heterocycles in moderate to excellent yields, in short reaction time.

Keywords: Flavone; Demethylation; Cyclization; Base-catalysis; Thiol

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When a peer-reviewed version of this preprint is available, this information will be updated in the information box above. If no peer-reviewed version is available, please cite this preprint using the following information:

Heck, R.; Anjos, T.; Giehl, M. R.; Schumacher, R. F.; Godoi, B. Beilstein Arch. 2021, 202158. doi:10.3762/bxiv.2021.58.v1

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