Benzothioxanthene dyes as fluorescent label for DNA hybridization: Synthesis and application

With naphthalimide as starting material, a new fluorescent benzothioxanthene dye with application for labeling oligodeoxynucleotide was prepared through imidation, deprotection and iodoacetylation. The benzothioanthene derivatives have DNA intercalation action and displayed a large Stokes' shift in Tris-HCl-H₂O buffer. The fluorescence intensity of the dye-labeled oligodeoxynucleotide, which was obtained through the connection of the dye to the sulphydryl functions of phosphate, was found to be sensitive to nucleobase mismatch in DNA sequence during hybridization, and so could be used as novel heterogeneous hybridization probes.