Organometallic nucleoside analogues: effect of hydroxyalkyl linker length on cancer cell line toxicity

A new series of chiral ferrocene derivatives containing both a hydroxyalkyl group and a thyminyl group on one cyclopentadienyl ring have been synthesised to probe structure–activity relationships in cancer cell line cytotoxicities. The stereoisomers of enantiomeric pairs of these so-called ferronucleosides have been studied and characterised by a combination of chiral analytical HPLC and single-crystal X-ray diffraction. Biological activity studies revealed that changing the length of the hydroxyalkyl group had marked effects on IC50 values, with compounds having shorter arms that more closely resemble endogenous nucleosides exhibiting lower cytotoxicities. The lipophilicities and electrochemical properties of this compound series have been studied to rationalise these trends and indicate future directions of study