Radiosynthesis of 1-(4-(2-[18F]fluoroethoxy)benzenesulfonyl)-3-butyl urea:: a potential β-cell imaging agent

Tolbutamide (1) is a sulfonurea agent used to stimulate insulin secretion in type 2 diabetic patients. Its analogue 1-(4-(2-[F-18]fluoroethoxy)benzenesulfonyl)-3-butyl urea (3) was synthesized in overall radiochemical yields of 45% as a potential beta-cell imaging agent. Compound 3 was synthesized by F-18-fluoroalkylation of the corresponding hydroxy precursor (2) with 2-[F-18]fluoroethyltosylate in DMF at 120degreesC for 10 min followed by purification with HPLC in a synthesis time of 50 min. Insulin secretion experiments of the authentic F-19-standard compound on rat islets showed that the compound has a similar stimulating effect on insulin secretion as that of tolbutamide (1). The partition coefficient of compound 3 between octanol/water was determined to be 1.3 +/- 0.3 (n = 5). Copyright (C) 2002 John Wiley Sons, Ltd.