Discovery of naphthalimide conjugates as fluorescent probes for α1-adrenoceptors

Abstract α 1 -Adrenoceptors ( α 1 -ARs), including at least three subtypes, α 1A , α 1B and α 1D , which play essential roles in G protein-coupled receptors (GPCRs), can convey multiple pivotal extracellular signals in varied tissues and organs. In this research, a series of napthalimide-based small-molecule fluorescent probes ( 1a – 1f ) for α 1 -ARs, including two parts, a pharmacophore (quinazoline and phenylpiperazine) for α 1 -AR recognition and a fluorophore (naphthalimide) for visualization, were designed and synthesized successfully. These compounds display excellent fluorescence property and high affinity to receptors, which were used successfully for in vitro visualization of α 1 -adrenoceptors.