Synthesis of novel fluorinated coumarins: Excellent UV-light excitable fluorescent dyes

Two new fluorinated fluorescent dyes, 6,8-difluoro-7-hydroxy-4-methylcoumar in (Marina Blue(TM)) and 3-carboxy-6,8-difluoro-7-hydroxycoumarin (Pacific Blue(TM)), exhibit excellent photophysical properties among a series of nov el fluorinated 7-hydroxycoumarins. Most of these fluorinated coumarins have quantum yields (0.63 to 0.89) equal to or higher than that of the parent c ompound (0.63), which, in combination with their lower pK(a)s and higher ph otostability, make them superior fluorescent dyes fbr use as reporter molec ules in biological systems. (C) 1998 Elsevier Science Ltd. All rights reser ved.