Synthesis and characterization of novel N-para-ferrocenyl benzoyl dipeptide esters

N-para-ferrocenyl benzoyl dipeptide esters 2-5 were prepared by coupling para-ferrocenyl benzoic acid I to the dipeptide ethyl esters GlyGly(OEt) 2, GlyAla(OEt) 3, GlyLeu(OEt) 4 and GlyPhe(OEt) 5. The compounds were fully characterized by a range of NMR spectroscopic techniques.. mass spectrometry (ESI-MS, FABMS, MS/MS) and cyclic voltammetry (CV). The a(1) and b(1) ions appeared at one mass unit less than the expected mass in the tandem mass spectra. The CV curves of compounds 2-5 exhibited quasi-reversible redox behavior similar to the Fc/Fc(+) redox couple and displayed oxidation potential values in the 50-55 mV range, against the Fc/Fc+ redox couple. (C) 2006 Elsevier B.V. All rights reserved.