Spectroscopic and structural studies of a new para-iodo-N-benzyl amide of salinomycin

Abstract A new para -iodo- N -benzyl amide of salinomycin was synthesized and characterized by NMR, FT-IR, DFT, single crystal X-ray diffraction and theoretical methods. The results obtained for the crystal, in solution and in gas phase provided evidence of pseudo-cyclic structure of this compound stabilized by intramolecular hydrogen bonds. It was shown that the compound studied forms stable 1:1 complexes with monovalent (Li + , Na + , K + , Rb + and Cs + ) and divalent (Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ ) cations demonstrating that the chemical modification of salinomycin carboxyl group considerably changes the ionophoretic properties of this antibiotic. For the first time, the ESI MS fragmentations of the complex of para -iodo- N -benzyl amide of salinomycin with Na + are also discussed in details.