Synthesis of Tc-99m-labeled, modified RNA

Abstract

The synthesis of Tc-99m-labeled, modified RNA is reported. This new class of radiopharmaceuticals is of potential interest as target specific imaging agents. The preparation of N 3S-conjugated RNA was achieved by coupling S-protected MAG 2-units to amino modified RNA in solution or on solid support. The starting S-protected MAG 2 building blocks ( 1R-S-CH 2-CO-Gly-Gly- 2R: 1R = Ac, tBu-S; 2R = OH, OSu) were obtained by a simple 4- or 5-step synthesis. The MAG 2-amide-RNA-conjugates were successfully Tc-99m-labeled with high yield and specific activities of 37MBq/nmol leading to 1:1-Tc-99m-N 3S-aptamers.