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Synthesis 2004(15): 2591-2593
DOI: 10.1055/s-2004-829194
DOI: 10.1055/s-2004-829194
PSP
© Georg Thieme Verlag Stuttgart · New York
Preparation of 5- and 6-Carboxyfluorescein
Further Information
Publication History
Received
3 March 2004
Publication Date:
13 August 2004 (online)


Abstract
Condensation of resorcinol with 4-carboxyphthalic anhydride in methanesulfonic acid gave a mixture of 5- and 6-carboxyfluorescein stereoisomers. These were separated by recrystallization from methanol- or ethanol-hexane to give 5- and 6-carboxyfluorescein, each in over 98% purity.
Key words
fluorescence - chromophores - condensation - heterocycles - regioselectivity