Novel functionalized benzimidazole-salicylic acid derivatives: synthesis, photophysical characteristics and biological applications.

Although the benzimidazole moiety is a versatile heterocyclic unit that has been widely applied in optical materials and medicinal chemistry, there are few bifunctional small-molecule benzimidazole derivatives with bio-activity and fluorescence. In this work, a series of novel benzimidazole-salicylic acid molecules were designed and synthesized; their optical properties were evaluated and their potential biological application was explored. The representative compound 5q exhibited excellent fluorescence properties, displaying blue imaging in HeLa cells and zebrafish. Additionally, it exhibited high selectivity for Fe3+ ions and demonstrated a notable inhibitory activity with IC50 = 6.86 ± 2.82 μM against SHP1PTP. Further effort was applied to explore the potential capability of compound 5q to reactivate the activity of SHP1 when inhibited by Fe3+ ions, indicating that compound 5q could be a fluorescent modulator to adjust SHP1 enzyme activity in biological systems.