A random screening of known compounds resulted in the discovery of two pyrazolopyrimidine structures, which acted as lead compounds for novel kinase inhibitors. Lead compounds can be obtained by screening synthetic compounds as well as natural ones. To this end, a random screening of chemicals produced by CIBA was carried out, revealing two chemicals (I and II) that acted as kinase inhibitors. The lead compound that was proposed to bind like CGP59326 was developed further by removing a primary amino group then adding an aromatic ring to fit the ribose pocket. Since both structures are pyrazolopyrimidines, it is tempting to propose that they both bind to the model binding site in the same manner.