Some pyrazolo [3, 4-d] pyrimidines, structurally related with allopurinol, a well known xanthine oxidase inhibitor, clinically used in the therapy of gout, have also been reported as potent inhibitors of xanthine oxidase and the growth of several human tumour cell lines. Considering the potential interest of this family of compounds, the aim of the present study was to synthesise and provide a full chemical characterization of new N-aryl-5-amino-4- ...