Synthesis of small organic molecules lies at the hard of modern drug discovery (1). Highthroughput biological screening (2) requires large diverse libraries of organic compoundswhose structures and physical properties (molecular weight, clogP, logS, number ofhydrogen bond donors and acceptors) obey certain rules such as rule of 5 (3) that increasethe probability of biological activity. In silico designed focused libraries of small molecules aresynthesized through attaching various functional groups to molecular cores (scaffolds) in afashion predicted to maximize ligand – target interactions (4).