Synthesis,spectral characterization and inhibitory potency of ferrocene‐containing mannosides towards type 1 fimbriated Escherichia coli

Escherichia coli adhesion to the bladder epithelium is mediated through recognition of the tissue‐surface mannosylated proteins with bacterial lectin FimH. The inhibition of this recognition‐dependent interaction has been recognized as a promising strategy for the development of an anti‐adhesion therapy. Mannosides with either aryl‐ or elongated alkyl‐functionalized aglycon portions have been shown to be potent inhibitors of FimH‐mediated adhesion. Thus, we have synthesized four mannose‐based bioorganometallics containing an extended alkyl chain between sugar and ferrocene components connected via ester linkage ( 14 (n = 4) and 15 (n = 5)) or amide linkage ( 18 (n = 3) and 19 (n = 4)). The novel bioconjugates were characterized using infrared and NMR (¹H, ¹³C, COSY, NOESY, HSQC, HMBC) spectroscopies, electrospray ionization mass spectrometry and high‐resolution mass spectrometry. Hemagglutination inhibitory assay of the novel bioorganometallics revealed an enhanced inhibitory potential in comparison to methyl α‐d ‐mannoside. Thereby, the bioconjugate 19 exhibited a twofold increase in inhibitory activity compared with 14 , 15 and 18 . Copyright © 2016 John Wiley & Sons, Ltd.