11C-Fixation Techniques

Abstract

This protocol describes the application of cyclotron-generated [¹¹C]CO₂ fixation reactions for direct ¹¹C-carboxylation reactions and [¹¹C]CO for ¹¹C-carbonylations. Herein we describe one-pot methods wherein the radioactive gas is first trapped in a reaction mixture at room temperature and atmospheric pressure prior to the radiolabeling reactions. Such procedures are widely applicable to numerous small molecules to form ¹¹C-labeled carboxylic acids, amides, esters, ketones, oxazolidinones, carbamates, and ureas. The steps for ¹¹C-fixation techniques described herein are tailored for a commercial automated synthesis unit and are readily adapted for routine radiopharmaceutical production.

Keywords: Carbon dioxide; Carbon monoxide; Carbon-11; Carbonylation; Carboxylation.