Synthesis of Bisboronic Acids and Their Selective Recognition of Sialyl Lewis X Antigen

The development of sensors that recognize Lewis oligosaccharides can help the diagnosis and early detection of cancer. Herein, we reported the design and synthesis of a series of anthracene-based bisboronic acids ( 9 a— 9 e) with different N-substituents near the boronic acid unit. Among them, compound 9 a could recognize sialyl Lewis X(sLe x ) with selectivity over other Lewis sugars, and could significantly stain sLe x -expressing HEPG2 cells with selectivity over the range of 0.1—10 μmol/L. Compound 9 a possibly has two properly positioned boronic acids caused by the steric hindrance by the near N -benzyl substituent group, which empower its sLe x selectivity and higher binding affinity.