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

N-para-ferrocenyl benzoyl dipeptide ethyl esters 2-5 have been prepared by coupling para-ferrocenyl benzoic acid 1 to the dipeptide ethyl esters GlyGly(OEt) 2, GlyAla(OEt) 3, GlyLeu(OEt) 4 and GlyPhe(OEt) 5 using the conventional 1,3-dicyclohexylcarbodiimide (DCC), 1-hydroxybenzotriazole (HOBt) protocol. The compounds were structurally characterized by a combination of NMR spectroscopic techniques and tandem mass spectrometry (MS/MS). The a1 and b1 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 behaviour.