The fluorescent markers based on oxazolopyridine unit for imaging organelles

Bioactive oxazolopyridine unit was used in the synthesis of fluorescent markers for specific organelles in this paper. The compounds 1a-c are linked with double bond between oxazolopyridine ring and photogenic precursors (3a-c). Compound 1a showed higher fluorescence yield (0.86 in THF), compounds 1b-c showed larger stokes shifts in DMSO. In lipid vesicles environment, they also showed good optical properties. In addition, the three compounds are biomarkers with lower cytotoxicity. Among them, compound 1a based on oxazolopyridine and coumarin unit is a dual targetable fluorescent marker for mitochondria and lipid droplets; while the other two compounds 1b-c are only biomarkers for lipid droplets.