Synthesis and characterization of hydroxyproline ferrocene-conjugated derivatives

Abstract EN

The synthesis of ferrocene-hydroxyproline amino acid conjugates was carried out using standard peptide coupling conditions in solution.

The coupling of hydroxyproline (Hyp) derivatives 3 and 4 with 1-ferrocene monocarboxylic acid (Fc-COOH) (1) gave 75-90 % yield of compounds 5 and 6, while the reaction with the glycine-hydroxyproline dipeptide 11 gave about of conjugate 12.

The reaction of 1, 1’-ferrocene dicarboxylic acid (Fc (COOH) 2) (2) with 3, 4 and 11 produced the corresponding Ferrocene-conjugated derivatives 7, 8 and 13 in acceptable yields (30-45 %).

All compounds were characterized by NMR, IR, MS and circular-dichrosim spectroscopy (CD).

CD-spectroscopy of compound 13 showed P-helical conformation of Fc in solution (1, 2’-conformer), and for compound 7 showed no absorption which suggests the 1, 3,- conformation pattern.