The Glutaminase-1 Inhibitor [[sup.11]C-carbony]BPTES: Synthesis and Positron Emission Tomography Study in Mice

Bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide (BPTES) is a selective inhibitor of glutaminase-1 (GLS1), consequently inhibiting glutaminolysis. BPTES is known for its potent antitumor activity and plays a significant role in senescent cell removal. In this study, we synthesized [[sup.11] C-carbonyl]BPTES ([[sup.11] C]BPTES) as a positron emission tomography (PET) probe for the first time and assessed its biodistribution in mice using PET. [[sup.11] C]BPTES was synthesized by the reaction of an amine precursor () with [[sup.11] C-carbonyl]phenylacetyl acid anhydride ([[sup.11] C]2), which was prepared from [[sup.11] C]CO[sub.2] and benzyl magnesium chloride, followed by in situ treatment with isobutyl chloroformate. The decay-corrected isolated radiochemical yield of [[sup.11] C]BPTES was 9.5% (based on [[sup.11] C]CO[sub.2] ) during a synthesis time of 40 min. A PET study with [[sup.11] C]BPTES showed high uptake levels of radioactivity in the liver, kidney, and small intestine of mice.