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

Abstract
Tolbutamide (1) is a sulfonurea agent used to stimulate insulin secretion in type 2 diabetic patients. Its analogue 1‐(4‐(2‐[18F]fluoroethoxy)benzenesulfonyl)‐3‐butyl urea (3) was synthesized in overall radiochemical yields of 45% as a potential β‐cell imaging agent. Compound 3 was synthesized by 18F‐fluoroalkylation of the corresponding hydroxy precursor (2) with 2‐[18F]fluoroethyltosylate in DMF at 120°C for 10 min followed by purification with HPLC in a synthesis time of 50 min. Insulin secretion experiments of the authentic 19F‐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 © 2002 John Wiley & Sons, Ltd.