Synthesis and photophysical properties of new fluorinated benzo[c]xanthene dyes as intracellular pH indicators

Bioorg Med Chem Lett. 2001 Nov 19;11(22):2903-5. doi: 10.1016/s0960-894x(01)00595-9.


Two new fluorinated benzo[c]xanthene dyes were synthesized by reaction of fluorinated 1,6-dihydroxynaphthalenes with 2,4- (and 2,5)-dicarboxy-3'-dimethylamino-2'-hydroxybenzophenone. The two critical fluorinated 1,6-dihydroxynaphthalene intermediates were prepared via a regioselective route. The fluorinated benzo[c]xanthene dyes exhibit desired lower pK(a) values (6.4 and 7.2, respectively) than their parent compound (pK(a)=7.5) while the pH-dependent dual-emission characteristics are well retained. Their cell-permeable esters have been prepared for intracellular applications.

MeSH terms

  • Benzopyrans
  • Fluorescent Dyes / chemistry*
  • Hydrogen-Ion Concentration
  • Indicators and Reagents
  • Molecular Structure
  • Naphthols / chemistry
  • Spectrometry, Fluorescence
  • Spectrum Analysis
  • Xanthenes / chemistry*


  • Benzopyrans
  • Fluorescent Dyes
  • Indicators and Reagents
  • Naphthols
  • SNARF dye
  • Xanthenes