[omega]-Difluoroamino carboxylic acids: Readily accessible fluorine-labeled fatty acid analogs

Abstract

15-Difluoroamino-pentadecanoic acid and 12-difluoroamino-dodecanoic acid were prepared by treating the corresponding lactams with F2 in aqueous acetonitrile. The intermediate N-fluorolactams were also isolated. Whereas isolated -CH2---F groups introduce considerable polarity into aliphatic chains, -CH2---NF2 groups did not. The -NF2 group thus appears to be a suitable isostere of the -CH3 group, where introduction of a 18F label is required for positron-based or 19F NMR imaging.