Previous studies demonstrated that HDpT chelators have potent anti-tumour activity. We have now designed and generated two new groups of chelators, HBpT and HNBpT. Comparing the three series of chelators, the HBpT analogues displayed highest anti- proliferative efficacy against SK-N-MC neuroepithelioma cells and was greater than other well known chelators (DFO, Triapine(r) and 311). Three analogues of the HBpT series displayed much greater anti-proliferative activity against SK-N-MC cells than normal MRC-5 fibroblasts, indicating their selectivity against tumour cells. Structure-activity...