Synthesis and characterization of fluorinated derivatives of cresolsulfonphthalein.

ABSTRACT

The reaction between dilute fluorine gas and cresolsufonphthalein in acetic acid was investigated. The mono-, di-, and trifluorinated cresolsufonphthalein derivatives were isolated and characterized. These compounds possessed the properties of pH indicators with biologically relevant pKa values (6.4-7.5) and the absorption maxima of the basic forms at 582-592 nm. This method can be used for synthesis of positron-emitting 18F-labeled pH indicators with potential application for non-invasive in vivo pH measurement in biological objects.