Synthesis, crystal structure, electronic spectroscopy, electrochemistry and biological studies of carbohydrate containing ferrocene amides

Abstract

A series of four new ferrocene–carbohydrate amides was prepared from pentose and hexose sugar derivatives. These include (5‐amino‐5‐deoxy‐1,2‐ O ‐isopropylidene‐α‐ d ‐xylofuranose)‐1‐ferrocene carboxamide (2a), (5‐amino‐3‐ O ‐benzyl‐5‐deoxy‐1,2‐ O ‐isopropylidene‐α‐ d ‐xylofuranose)‐1‐ferrocene carboxamide (2b), (methyl‐6‐amino‐6‐deoxy‐2,3‐ O ‐isopropylidene‐β‐ d ‐ribofuranoside)‐1‐ferrocene carboxamide (2c) derived from furanose sugars and (6‐amino‐6‐deoxy‐1,2:3,4‐di‐ O ‐isopropylidene‐α‐ d ‐galactopyranose)‐1‐ferrocene carboxamide (2d) derived from pyranose sugar. The compounds were characterized by spectroscopic means and the structure of amide derived from α‐ d ‐xylofuranose (2a) was determined by X‐ray crystallography. The electronic and optical properties of the compounds were studied by means of cyclic voltammetry and absorption spectroscopy. The UV and electrochemical studies of these compounds, performed in aqueous solutions under physiological conditions (at pH 7.4), confirmed their stability. These results indicated that the compounds were suitable for conducting biological studies. The CD spectral analysis displays the effect of sugar substituents on the compounds. The cytotoxicity and antimicrobial activity of these conjugates were investigated on different cancer cell lines and microbes respectively. The degree of inhibition varied over a broad spectrum of Gram‐ positive and Gram‐negative bacteria. In addition, the compounds also exhibited antioxidant properties. Copyright © 2012 John Wiley & Sons, Ltd.