Pyrazole-type cannabinoid ligands conjugated with fluoro-deoxy-carbohydrates as potential PET-imaging agents: Synthesis and CB1/CB2 receptor affinity evaluation

A novel class of cannabinoid ligands was synthesized in good overall yields by means of oxime-bio-conjugation between hydroxylamine-functionalized Rimonabant-type pyrazoles and fluoro-deoxy-carbohydrates (D-2-fluoro-deoxy-glucose, FDG, and D-5-fluoro-5-deoxy-ribose, FDR). FDR proved to be superior to FDG for bio-conjugation, as it occurred in milder conditions and at faster rate (rt, 20 min vs. 100 degrees C, 30 min). All of the title compounds showed relatively modest affinity for the CBI receptor (high nanomolar range) and selectivities vs. the CB2. (C) 2013 Elsevier B.V. All rights reserved.