First step to 19F Hyperpolarization of Biocompatible Substrates Generated via Parahydrogen-Transfer

Introduction A complete lack of natural background signal in body tissues and advantageous MR characteristics like a 100% natual abundance and 84% MR sensitivity in comparison to H qualify fluorinated substrates as preeminent reporter molecules for MRIand MRSinvestigations. Even the simultaneous detection of multiple signals from separate molecules in MRS investigations is facilitated by a wide chemical shift range. However, an effective signal enhancement is advantageous for a successful application of such agents as a diagnostic tool as their concentration usually is limited in vivo. PHIP hyperpolarization (ParaHydrogen Induced Polarization) is a promising strategy towards MR-based molecular imaging and first images of a F hyperpolarized substrate as a model compound could be obtained. A prerequisite for an implementation of this method in living systems is the biocompatibility of these contrast agents. Many pharmaceuticals contain a fluorine atom allowing detection of pharmacokinetics and their metabolism. Even passive substrates like perfluorinated alkanes can be used to investigate anatomical properties such as lung volume. In this contribution we chose a semifluorinated alkane as an exemplary, physiologically compatible target molecule. The characteristics of semi-fluorinated alkanes are similar to perfluorinated alkanes. They show an enhanced solubility for oxygen and are nontoxic. Thus they could be used as passive contrast agents. In analogy to perfluorinated alkanes they might also be applied for in vivo monitoring of inflammatory processes.