Synthesis 2016; 48(11): 1622-1629
DOI: 10.1055/s-0035-1561603
© Georg Thieme Verlag Stuttgart · New York

A Practical Synthesis of 6,8-Difluoro-7-hydroxycoumarin Derivatives for Fluorescence Applications

Jeff K. Kerkovius
Department of Chemistry and Chemical Biology, University of British Columbia, Okanagan, Kelowna, BC, V1V 1V7, Canada   Email:
Frederic Menard*
Department of Chemistry and Chemical Biology, University of British Columbia, Okanagan, Kelowna, BC, V1V 1V7, Canada   Email:
› Author Affiliations
Further Information

Publication History

Received: 03 February 2016

Accepted after revision: 08 March 2016

Publication Date:
19 April 2016 (online)


A practical synthesis for 6,8-difluoro-7-hydroxycoumarin-3-carboxylic acid – one of the most widely used coumarin fluorescence imaging dye for bioconjugation – is reported. The synthesis was optimized for a preparative scale to obtain 14 g of the fluorescent coumaryl acid, 6,8-difluoro-7-hydroxycoumarin-3-carboxylic acid. Using this sequence, the preparation of its NHS ester requires a single chromatographic separation for a total of eight synthetic steps. Coupling of the key coumaryl NHS ester is also demonstrated with an unprotected hydroxyamine linker chain for further derivatization. This report provides a convenient access to the fluorinated dye for research labs as an alternative to currently cost-prohibitive commercial sources.

Supporting Information

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