Synthesis and cellular uptake of boron-rich pyrazolopyrimidines: exploitation of the translocator protein for the efficient delivery of boron into human glioma cells.

New 1,2-closo- and 7,8-nido-carboranylpyrazolopyrimidines bind to the translocator protein (TSPO) with high affinity, providing the first evidence of a unique two-site binding profile for the closo-carborane derivative. The boron-rich compounds can also deliver boron to human glioma cells far more effectively than clinical agents used in boron neutron capture therapy (BNCT).