Isotope-Labeling of the Fibril Binding Compound FSB via a Pd- Catalyzed Double Alkoxycarbonylation.

We have synthesized two isotopically labeled variants of the β-amyloid binding compound FSB possessing 13C-labels on the two terminal aryl carboxylic acid moieties. One of these was also fully deuterated on the olefinic spacers. The 13C-isotope labeling was achieved applying a Pd-catalyzed methoxycarbonylation of the corresponding aryl chlorides with externally (ex situ) generated 13C -labeled CO. Application of the Shirakawa-Hayashi protocol for the Pd-catalyzed reduction of a dialkyne intermediate using D2O allowed for the selective deuterium labeling of the two trans-C,C double bonds of FSB. [ABSTRACT FROM AUTHOR]