Radiosynthesis, and Evaluation of [F]CBD-2115 as a First-in-Class Radiotracer for Imaging 4R-Tauopathies.

CBD-2115 was selected from a library of 148 compounds based on a pyridinyl-indole scaffold as a first-in-class 4R-tau radiotracer. In vitro binding assays showed [H]CBD-2115 had a value of 6.9 nM and a nominal of 500 nM in 4R-tau expressing P301L transgenic mouse tissue.