The present patent application introduces methods for generating mixture compound libraries from a drug lead. The mixture compound libraries are then screened for the discovery of modified drug lead compounds which possess desired improved drug properties. The process utilizes a non-selective reaction to modify the drug lead compound structure. Compared to existing methods of modifying a drug lead compound, this new method can modify more structural positions of a drug lead compound. As a consequence, there will be greater probability of finding a product with improved drug properties.