1. Department
of Nuclear Medicine, Molecular Imaging and Radiochemistry, Friedrich Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage
6, Erlangen D-91054, Germany
2. Department
of Chemistry and Pharmacy, Medicinal Chemistry, Emil Fischer Center, Friedrich Alexander University Erlangen-Nürnberg (FAU), Schuhstrasse 19, Erlangen D-91052, Germany