Direct Synthesis of Tricarbonyl(cyclopentadienyl)rhenium and Tricarbonyl(cyclopentadienyl)technetium Units from Ferrocenyl Moieties − Preparation of 17α-Ethynylestradiol Derivatives Bearing a Tricarbonyl(cyclopentadienyl)technetium Group

The preparation of new tricarbonyl(cyclopentadienyl)rhenium and tricarbonyl(cyclopentadienyl)technetium derivatives is described. The approach used was applied to a cold target model, 17α‐ethynylestradiol substituted at the 17α position by a ketotricarbonyl(cyclopentadienyl)rhenium group. The novel organometallic reaction applied here, when extended to potential radiopharmaceuticals, consists of a cyclopentadienyl‐ligand transfer between ketoferrocenes and fac‐[99mTc(H2O)3(CO)3]+ in a water/DMSO 1:1 mixture. This reaction lead to the synthesis of a new estradiol derivative, labeled with 99mTc. The synthesis of another product was performed by using [99TcCl3(CO)3]2− as the Tc precursor and its X‐ray crystal structure was determined. In each case high yields were obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)